BSI Journal - Online Archive


A non-profit corporation whose purpose is to promote and maintain public and scientific interest and research in bromeliads throughout the world.

There are 4 classes of membership: Annual $10.00; Sustaining $15.00; Fellowship $25.00; and Life $200.00. All memberships start with January of the current year.

Address all correspondence to:
The Bromeliad Society, Inc.
P. O. Box 3279
Santa Monica, Calif. 90403
PresidentElmer J. Lorenz, Calif.
1st V.P.Leonard Kent, M.D., Calif.
2nd V.P.W. R. Paylen, Calif.
Rec. Secy.Jeanne Woodbury, Calif.
Corres. Secy.Kathy Dorr, Calif.
Treas.Joyce Lorenz, Calif.


1974-1977: Eloise Beach, Kathy Dorr, George Kalmbacher, Fritz Kubisch, W. R. Paylen, Amy Jean Gilmartin, Robert Read, Edgar Smith.

1975-1978: Jeanne Woodbury, George Anderson, Charles Wiley, Ervin Wurthmann, Victoria Padilla, Wilbur Wood, Thelma O'Reilly, David H. Benzing.

1976-1979: Robert G. Burstrom, Leonard Kent, Elmer J. Lorenz, Edward McWilliams, Harold W. Wiedman, Tim Lorman, Sue Gardner, Herbert Plever.


Adda Abendroth, Brazil; Luis Ariza Julia, Dominican Republic; David Barry, Jr., USA; Olwen Ferris, Australia; Mulford B. Foster, USA; Marcel Lecoufle, France; Harold Martin, New Zealand; Dr. W. Rauh, Germany; Raulino Reitz, Brazil; Walter Richter, Germany; L. B. Smith, USA; R. G. Wilson, Costa Rica.


Published six times a year: January, March, May, July, September, November. Free to members.

Individual copies of the Journal, $2.00


Collecting in Nicaragua
  Frank Hausman147
  Lloyd P. Champagne150
Forcing Bromeliads to Bloom
  Kathy Dorr154
Up to Date on Florida's Native Tillandsias
  Jim Thompson156
For the Connoisseur158
New Affiliates159
Tillandsia Andreana-Tillandsia Funckiana
  Alfred Blass160
Regional Reflections163
Aechmeas are for Everyone168
The Structure of the Bromeliad Trichome
  David H. Benzing170
Notes from Australia180
Neoregelia 'Green Apple'
  Herbert H. Hill, Jr.192


Guzmania diffusa L.B. Smith
Photo by Alexander Hirtz, Ecuador

Editor: Victoria Padilla

Editorial Board: Dr. R. W. Read, Identification; Dr. W. Rauh, Identification; Mrs. Kathy Dorr, Advertising; Elmer J. Lorenz, Index; Lawrence Mason, Jr., Science; Robert Burstrom, Regional; Edgar Smith, Regional.

Articles and photographs are earnestly solicited. Length is no factor. Please mail copy and all questions to the Editorial Office, 647 South Saltair Ave., Los Angeles, California 90049.

Collecting in Nicaragua


D. W. Rock
Aechmea bromeliifolia

The morning after Christmas of 1976 your correspondent and 14 avid orchid collectors, again led by my friend Fred Fuchs, took off and flew to Managua, Nicaragua. There we were met by a special minibus, and soon we were on our way to Santa Maria de Ostuma. This is a most beautiful spot, over 4,000 feet in elevation, with spectacular views of hills and valleys. The rustic hotel is both highly interesting and comfortable and serves the most superb food. On the trees in the gardens, I spotted Tillandsia standleyi, T. butzii, and a catopsis in flower.

On the following Monday morning we set off for Esteli. This proved to be dry, scrubby woods country, with some tree cactus and an odd clambering philodendron whose thick, scaly trunk displayed only a few leaves at its tip, the leaves were being shed as the severe dry season had commenced. Tillandsia caput-medusae was scattered, T. brachycaulos was plentiful, and T. dasyliriifolia was found. We rode on down to the Rio Esteli for lunch, passing interesting plants on the way: some hechtias, an agave species, and one solitary pitcairnia clump which was not in flower. We ate our lunch in a large open-sided shed near the river. There were piles of smelly seed potatoes, chickens scratching around — certainly not the most romantic of sights. In the creek I found large snails, and several of our group helped me to collect them. On the way back up the hills, we stopped for orchids and found clumps of Aechmea bromeliifolia.

The next day we were rolling over and down the mountains in another direction, beyond Jinotega, where some cliffs almost reached the road. There, before us on the other side, was a beautiful artificial lake. We made our way up the overgrown cliffs and found agaves, hechtias, a small grey cactus, sobralia orchids, and various tillandsias, including schiedeana and juncea. The view over the lake and valley from the top of the ridge was beautiful. Coming back, we stopped at a road cut in the lush mountains, and among the reed stem epidendrums I found one Pitcairnia heterophylla and saw a Tillandsia standleyi in flower high up on the cliff.

That Wednesday we moved, via old back roads, to Managua, passing Muy Muy and collecting near Tierra de Azul. It was here, as I remember, that some of us saw a beautiful red leaved guzmania, which was way up in the crotch of a tall gumbo limbo tree. We tried several times with long poles to get it, but could not.

The next morning we went to the lava fields around Volcan Santiago, which proved a most fascinating place. Stunted gumbo limbo and native frangipani trees, the former, with their copper-colored bark reminding us of the Florida keys. At this locality, Luella rubescens was in flower everywhere on the trees and on the lava rock — a really beautiful sight. We found clumps of a tillandsia, new to me. Some collectors said it was T. baileyi, but George Kalmbacher called it T. polystachia. We had seen miles and miles of the red-leaved Bromelia pinguin, but nowhere could I find small plants. However, here, in the extremely dry rock, were groups of them; badly dehydrated, the plants had actually become smaller. After we dug up a plant and peeled off the outer dead parts, the live part was small and easily carried. In the sun they were most attractive, having beautiful red leaves at all stages of growth.

Friday some of us went farther toward Masaya, along the lava fields, and here gumbo limbo and other stunted trees had branches covered with red leaved Tillandsia ionantha. We found few orchids, and the only other tillandsia was T. schiedeana. On our return, we stopped at the Laelia rubescens site to pick up the others, and there saw two little Indian boys walking along the road with large bouquets of the orchid blossoms, which were for the market in Masaya.

This was now New Year's Eve — the hotel had a turkey in the patio fattening up, and after our dinner that evening, the turkey was no more. Delicious! Then for dessert we went through a gallon of ice cream, half mango and half pineapple. We just passed it around the table several times.

January 1 was a memorable day. Our destination was some scrub forests near Rivas, which is near the Costa Rica boundary. There were a few clumps of a very handsome, spiny Bactris palm here. We walked in this area looking for two members of the group that had strayed from the fold for over two hours. It was a beautiful area in a lush forest and a babbling brook, and everywhere gorgeous butterflies in profusion. Our lost friends found their way back to the bus before we finally arrived.

Sunday of the new year was spent cleaning plants and assessing our findings. That evening we flew back to Miami to end a fascinating holiday in Central America.

New York

Endeavoring to promote flower advancement with bromeliads, F. Escher and H. Strech of Germany experimented with a number of bromeliads. Three-year-old plants of Guzmania monostachia, Guzmania lingulata minor 'Orange', Nidularium billbergioides and Aechmea fulgens var. discolor were sprayed with 50 ml Ethrel (ethephon)/2000 water or drenched with 50 ml Bromblute/950 ml water (675 ml water of Aechmea) on March 17. Their growth and flowering were studied up to November 20. All species flowered earlier after spraying with ethephon and made saleable plants, and only the nidularium failed to flower after drenching with Bromblute. Of the controls, at the end of the trial only, A. fulgens had flowered and had done so very slowly. On October 20 plants treated with Bromblute were at least one-third larger than those treated with ethephon. The only adverse side effects were leaf spotting with G. minor. When plants of G. minor with a second crop of 6 to 8 flower buds were sprayed with ethephon, these colored and opened within about six weeks.



The subject may sound mundane. However, I suggest to you that it is the single most important topic in the culture of bromeliads, as it probably is in the culture of all plants. I further submit that it is also the most frequent cause of dead plants in the entire ornamental plant business.

It is impossible to talk about watering plants without considering many other factors which also affect watering. These other factors include the type of soil, the surrounding humidity, the size of the pot, the number of plants in each pot, the amount of sunlight, surrounding temperature, air flow, to mention the more important ones. Therefore, it is almost useless to ask your fellow-growers how often they water. What works for them may not work for you, due to the listed variables. The first thing we usually learn about bromeliads is that bromeliads do not like wet feet. This is the first thing I learned about them, and I am sad to say I have not followed the rule sufficiently. It is not at all sufficient that there merely be good drainage in the pot. The fact of the matter is that the roots of bromeliads generally like to be thoroughly (I said thoroughly, I mean it, and I repeat it) dry between waterings. There is only one proper way to determine when to water, and that is to feel the soil. I suggest to you that as long as there is any coolness whatsoever to the soil, that it is not time to water.

As the years go on, I find myself mixing an ever-looser and faster drying soil. I believe that it really doesn't matter one whit what kind of mixture you use, as long as it is fast drying. I have experimented and continue to experiment constantly with different potting mixtures. I find that the slowest drying soil of all is any soil with a lot of leaf mold. Leaf mold retains water longer than any other medium, and has the further disadvantages of souring when it remains damp. Also, leaf mold packs and prevents aeration of the roots. Other undesirable substances in high concentrations are sphagnum moss, saw dust, wood shavings, and any other type of organic matter that has a tendency to pack. Surprisingly, sharp sand, by itself, is very slow drying. On the other end of the spectrum, whatever you use, I advise very high concentrations of perlite, shredded tree fern, and/or hadite in order to keep the soil very loose and well aerated and rapidly drying. This becomes especially important when a grower grows bromeliads along with various other plants which require en masse watering. As one's collection grows, it becomes increasingly impossible to give individual attention to the plants. Therefore, that all should be watered at the proper time can only be accomplished by using the proper size of pot and the proper moisture retaining properties of the soil in order to get the proper amount of drying all at the same time. Even then it becomes difficult. I keep several plastic gallon jugs around my greenhouse filled with water, so that I may give some individual plants a drink as I make my twice daily tour, as they may need it, awaiting the en masse watering. As one's collections grows, it is likely that you will find that watering becomes less frequent due to the increasing amounts of water which must be evaporated, the closeness of the pot plants, decreased sunshine and air circulation, and all of the other factors listed above. This is especially true when one moves into a greenhouse. Again, it becomes more true when one may tend to close up a greenhouse for the winter, with the resulting coolness of winter, decreased fresh air and circulation, as well as decreased sunlight, slower growth, and lesser need for water.

Most of the bromeliads I have seen killed have been killed with tender loving care. Surely, we have all seen some plants neglected to death, but I consider this the exception. I have never killed a bromeliad with lack of water. I tried to do this this past summer, and I failed. I took a pot of Neoregelia 'Painted Fingernails' to one of the far corners of my yard, out in the midday sun. I never watered it once throughout the entire summer. It survived on rain and dew only. I even ran across it inadvertently a couple of times with my tractor wheel. We went through at least two dry spells during the summer without any rain whatsoever for six weeks. When I brought this plant indoors in October, it was beautifully healthy, hardy, and growing well. Yes, it was also dry. Almost none of my bromeliad-nut friends have succeeded in raising guzmanias. I am having wonderful luck. I am sure the reason for my good luck is that I use this extremely coarse soil, a small pot, a lot of air, and even a substantial amount of direct sunshine. My dear friend, Art Boe, who advertises in this journal, and I, have had some vigorous but friendly arguments over planting with sphagnum moss and tying the moss to the plant. He even does this with seedlings, even guzmania seedlings. He claims that this reduces the shock of transplanting. I agree with his contention that it may help support a plant in the soil, but I also insist that it is a sure fire method of rotting the plant.

I am constantly reading references in the Journal about browning and softening at the bases of the leaves. Without exception, this is always referred to as fungus rot. I stress the fact that I am not a professional botanist, nor a microbiologist. Even so, I insist that any fungus that may occur is a purely incidental phenomenon and is not the cause of this leaf rot. The reason is, naturally, water. Any time you have a browning or a softening or rotting of the lower leaves near the base of the plant, it is due to wet rot. If you are having to remove leaves from the base of the plant, cut down on your watering. The problem is, is that it may take months after the excessive watering before the rot becomes evident. In the extreme cases, it is possible to smell the sour water. I have a general rule in life, when in doubt, don't. This is a good rule for watering bromeliads. As a physician, I have been brought up on the enormous life saving values of fluid and electrolyte replacement in humans. This alone has saved more infant lives than any other phenomenon in medical practice. I truly suffer as I walk through the greenhouse, noting the dryness of the plants, and I so terribly want to water them, but I don't. It is even a good idea to dump the water out of the cup of certain plants as Tillandsia xerographica, and even more so during the winter.

I have already referred to outdoor humidity. Certainly, one has to take these admonitions in view of the fact that the humidity in Louisiana is often 100%, and I have seen it as low as 6% in Denver. We have never seen 6% humidity in Louisiana. I have seen my brother thoroughly soak an outdoor garden in Denver, and one hour later, it is bone dry. It naturally follows that over-watering is much less a hazard in areas of extremely low humidity.

I also suggest that most bromeliad diseases result from over-watering. I certainly know that scale is one disease that I have totally eliminated by dryness. About the only "disease" that I have are crickets and/or grasshoppers that inhabit the cup of the guzmanias and cut the leaf in order to pull it over for protection.

During the cool, over cast, wet days of winter, my greenhouse is like a terrarium. The moisture condenses on the cool roof and literally rains or drizzles in the green house. It is during this type of weather that I water as little as every 18 days. I never mist. The humidity is always so high in Louisiana, that it seems senseless to me to mist. How much higher humidity can one get at 100%? When I do water, I find it necessary to soak everything thoroughly in order to be sure that none of the plants become neglected. As I mentioned, I water everything en masse, without any individual attention. Now, misting may be useful in some of the drier regions. However, I find that so many people who mist, don't know when to stop, and so over mist as to substantially soak the plant. Even in the hottest, driest days of summer, I never water more than every 5 days.

I have also found that any kind of small electric fan is very useful to keep the air moving. The only beneficial effect that this can have is to hasten the drying process. In so doing, it guarantees the drying of the plants which may be somewhat crowded and less well aerated. It also follows that during the winter time, the cooler that you keep your plants, the less water they need. There are several reasons for this. Evaporation is slower, plant growth is slower and requires less water, and there is less danger of excessive drying out (if that is in fact possible).

I don't talk to my plants except to warn them to shape up or ship out. I think that the plant talkers, while they are talking to their plants, are also feeling the soil.

Baton Rouge. Louisiana

After lingering for quite a few years as a horticultural curiosity or at best a research tool for studying plant nutrition, hydroponics has suddenly appeared in new forms. A whole new science of non-soil culture is emerging, and its implications seem both promising and exciting. One of the most interesting developments is organic hydroponics. In an 18-month rooftop gardening project in Montreal, funded by the Canadian government, tomatoes were grown in perlite, vermiculite and sand, and watered regularly with a solution of 1 teaspoon of bloodmeal per gallon of water. Yields were 1/3 higher than for plants grown in soil. This same treatment might prove to be successful in the growing of certain bromeliads and would certainly be well worth a try.

Forcing Bromeliads to Bloom



Articles appear frequently concerning the forcing of bloom in bromeliads. They range from using "apples" to chemicals. These articles, in turn, generate the questions as to what should be used and where the chemical can be obtained as well as "what really happens?"

Judging by a number of examples I have seen, I would suggest that forcing be left to the large growers, who can afford to have problems and/or failures.

The picture shows Aechmea chantinii which was forced. The chemical was used only on large plants; however, all offshoots as well were brought into bloom, even though they were not mature. In this instance, all the plants died after blooming without producing offshoots. Apparently the small offshoots were not capable of blooming and producing offshoots.

A number of neoregelias that were chemically treated became so "excited" they produced their inflorescences from outside the base of the plant, instead of in the normal manner. These were mature plants at the time they were treated. The inflorescences were not very attractive. The plants died before producing the normal number of offshoots, although they did yield more than one.

Using an apple probably does less damage than other means; however, from the letters I have received, there is a misunderstanding concerning the method. The apple core or apple is NOT placed in the throat of the plant. It is simply placed in the plastic bag, along with the plant.

Experience has shown that in most cases if your plant is mature and really ready to bloom and if you follow the following simple rules, it will produce an inflorescence without the use of chemicals.

Allow the plants to be dry for ten days or two weeks. Move the plant, if possible to another area, perhaps to receive a little more light or a little less light. Apparently the shock of change helps to cause the plants to be more likely to bloom.

Remember, before you start experimenting, all bromeliads bloom in nature without the help of chemicals.

Lakewood, California


Bromeliads — A Cultural Handbook — New, revised, enlarged edition. No bromeliad grower should be without this valuable how-to book.

A Glossary for Bromeliad Growers — Compiled by Victoria Padilla and illustrated by Sue Gardner. See page 183 for details on how to order.

Mr. Moir of Honolulu writes that the picture which he submitted for the cover on Issue No. 2 for this year was taken by Robert Sato in the pouring rain. It is a Neoregelia princeps hybrid.

Up to Date on Florida's Native Tillandsias


T. usneoides
T. recurvata
T. setacea
T. simulata
T. juncea
T. festucoides
T. balbisiana
T. circinnata
T. flexuosa
T. pruinosa
T. fasciculata
T. polystachia
T. utriculata
T. valenzuelana
T. incurva
T. flabellata
T. ionantha
T. usneoides
T. recurvata
T. setacea
T. bartramii
T. balbisiana
T. circinnata
T. flexuosa
T. fasciculata
T. polystachia
T. utriculata
T. valenzuelana

Misinformation, cross-fertilization, and lack of updated material have created a list of Florida's native tillandsias much out of proportion with what one would actually find in the wilds.

T. usneoides is T. usneoides and T. recurvata is T. recurvata, but T. setacea is a name of dubious value. The name T. setacea applies to the short grasslike tillandsia found in the southern half of Florida, whereas a similar plant found from there northward through Carolina and called variously T. setacea, simulata, festucoides, or juncea is a complex now called T. bartramii. (see Phytologia, Notes on Bromeliaceae, XXIV, by L. B. Smith, Vol. 13, p. 454.)

T. juncea is totally misapplied to Florida, according to Dr. Smith, as its native range is Mexico and the West Indies to Peru and Bolivia. T. festucoides is a similar case, its native range being Mexico and the West Indies through Central America. T. balbisiana collected in Florida averages between 6 and 10 inches in height, while its many natural hybrids sometimes reach 25 inches. T. circinnata remains fairly standard in size, as does T. flexuosa. T. pruinosa, while considered native by many, appears to be a naturalized immigrant, since its native range is Cuba to Brazil. Another Cuban far afield is T. fasciculata var. clavispica found in the Everglades growing alongside T. fasciculata var. densispica, our Florida native. T. fasciculata's many hybrids are extremely difficult to separate, as are the many forms of T. polystachia. The type plant for either is difficult to pinpoint 'in Situ.'

T. utriculata abounds in the state and T. valenzuelana is found in many places south of central Florida. T. incurva is a vriesea now, and probably never was a native, as its native habitat is a mountainous rain forest. The few T. flabellata and T. ionantha found occasionally are surely escapees because they do not fit the surrounding botanical family grouping.

Plants do not just appear in the wild. They follow logical development from simple to complex, and although some steps may be missing along the way they still have a certain position and order which can often help establish whether a certain plant is a native (developed there) or naturalized (relocated there after developing elsewhere). Well, our list of native tillandsias is certainly shorter but also hopefully more in keeping with what might expect to find in the wilds of Florida.

Orlando, Florida

F. Escher and H. Strech of the German Federal Republic have been experimenting with the control of flowering in guzmanias. Plants were sprayed once with Ethrel (ethephon) at monthly intervals between April and December. For Guzmania minor 'orange' treated in months from April to September the average time from induction treatment to flowering (plants ready for sale) was 54.3 days. For G. monostachia the corresponding time was 38.7 days. Plants treated in October to December generally took longer to flower, being retarded by the short days and lower light intensity.

For the Connoisseur

Guzmania diffusa L. B. SMITH

This magnificent guzmania, illustrated on the cover, was first described by Lyman B. Smith in 1948, so it is a comparatively recent arrival to the bromeliad scene. It is not readily available in nurseries but is listed in the trade.

It is native to Colombia and Ecuador, where it is found on trees in moist open woods and in cloud forests at altitudes ranging from 8,500 to 10,000 feet. It is a large plant, similar in size to many of the high-altitude guzmanias found in these countries. It ranges in height from 3 to 6 feet, with the rosulate leaves averaging from 24 to 32 inches in length. The erect scape rises well above the rosette; its bright red coloration making a brilliant foil to the many diffuse branches with their yellow petaled flowers. (For a complete description, see Smith, The Bromeliaceae of Colombia, page 204, and Gilmartin, The Bromeliaceae of Ecuador, page 226.

It has been this writer's experience that the large high-altitude guzmanias are difficult to maintain in optimum conditions under her growing environment. The cold rarified air of the Andes is not easy to duplicate in southern California with its dry desert winds and hot arid summers. In more northerly areas around Seattle where odontoglossums flourish, these guzmanias might do well. They would need an air-conditioned greenhouse, such as is suitable for the cool orchids. They present one difficulty, however, and that is their size, for when they reach maturity and flowering stage, they take up much precious bench space. However, most of these guzmanias are so elegant and so eye-arresting, they are well worth experimenting with and the space they may take.


Dr. Werner Rauh's Bromelienstudien No. 6 has just been received. In it he describes 3 new tillandsias, 2 new vrieseas, 1 new guzmania, and 1 pitcairnia. All are excellently illustrated with photographs and line drawings. Copies of this invaluable set may be obtained from Abbey Garden Press, Box 2010B. Santa Barbara, California 93105. Price for this latest booklet is 11,60 DM. Descriptions are in German.

Affiliates Organized 1975-1976


Bromeliad Society of Tucson
Mr. D. W. Smith, Pres.
2141 E. Spring St., Tucson, Arizona 95719


Long Beach-Lakewood Bromeliad Study Group
Roger L. Vandermeer, Pres.
9892 Orangewood Ave., Garden Grove, Ca. 92641

Saddleback Valley Bromeliad Society of El Toro
Mrs. Kathy Dorr
6153 Hayter Ave., Lakewood, Ca. 94707

Central Coast Bromeliad Society
William Netherby
379 Highland Drive, Los Osos, Ca. 93402


High Country Bromeliad Society
Lawrence Mason, Jr., Pres.
American Medical Center
6401 W. Colfax Ave., Lakewood, Colorado 80214


Sarasota Bromeliad Society
Mr. Donald Roehr, Pres.
1306 N. Orange Ave., Sarasota, Florida 33577


Indianapolis Bromeliad Society
Ms. Elissa W. Hafsten, Pres.
155 W. 73rd St., Indianapolis, Ind. 46260


Acadiana Bromeliad Society
Mr. Macy S. Dennis, Pres.
2 Brentwood Circle, Lafayette, La. 70501


South Eastern Michigan Bromeliad Society
Mr. Wm. Vilders, Sr., Pres.
18106 Hamburg St., Detroit, Michigan 48205


Mississippi Bromeliad Society
Mrs. John S. Watson, Corr. Secretary
1842 Howard St., Jackson, Mississippi


Tarrant County Bromeliad Society
Mr. La Verne Edwards, Pres.
5501 Wharton St., Fort Worth, Texas 76133

Tillandsia Andreana — Tillandsia Funckiana


Upper Plant — T. funckiana, showing exserted stamens.
Lower Plant — T. andreana.

(Translated by Walter Goddard)

Even the most competent taxonomist sometimes has a difficult time differentiating between two similar species. This is especially true when one is working exclusively with dry herbarium material, for the decision as to how to classify a "border case" depends more or less on the supposition of the nomenclator. Many species show forms of transmutation which make taxonomical decisions even more difficult, I have observed in my collection the following forms of transmutation:

Tillandsia caput-medusae and T. circinnata

T. purpurea, straminea, and cacticola

T. sphaerocephala, calocephala, and nana

T. incarnata and macbrideana

T. brachycaulos and capitata

T. concolor, acostae, and fasciculata

T. arequitae, boliviensis, and lorentziana

T. aurea, aureo-brunea, and humilis

T. vernicosa and didisticha

Some of these plants, I believe, represent not separate species, but are just varieties. I would like to emphasize that the above mentioned transmutations are not hybrids nor are they artificial cross-pollinates. Serious collectors, who specialize in certain plant families, may be helpful to science by reporting their observations. I had the pleasure some years ago to show Dr. Lyman B. Smith the obvious differences between T. magnusiana and T. plumosa, which were originally registered as one single species.

With this article I would like to prove that T. andreana and T. funckiana are definitely two separate species.

For several years I have grown three different clones of T. funckiana, all of them coming from Venezuela. One of these plants is particularly beautiful, but regrettably is rather rare. This plant grows much larger than the standard form, and the leaves are strongly recurved. I would like to see this species named Tillandsia funckiana var. nov. recurvifolia.

I have two different clones of T. andreana under cultivation. One is distinguished by having leaves covered with silvery green scales. The other, being rather rare, has yellowish green leaves and shows fewer scales, T. andreana is found exclusively in Colombia, but the localities where the two different kinds come from are more than 1000 km apart. Mr. Thiken, an ardent plant collector, was the first one to discover these tillandsias and to introduce them to the European market.

All T. funckianas are strongly caulescent, whereas T. andreanas never form stems. But the main difference between the two species becomes evident when one studies the stamens, which can be easily seen above the petals of T. funckiana, while they are completely recessed within the red petals of T. andreana.

As the differences in appearance are so obvious and no transmutations in nature have been discovered, I believe that we have here two separate species which might be somehow related.

In my estimation both plants represent some of the most beautiful of the miniature tillandsias. Their brilliant red bracts are extremely large for such small plants. At one time I had 36 flowers growing on a single branch of T. funckiana. Both species are prolific seed bearers, and seedlings grow well when protected from bright sun light.

I think that Mez was mistaken when he gave the habitat for T. funckiana as Merida in Colombia. Collectors who have worked in this area recently occasionally found T. andreana, but never T. funckiana. T. funckiana has been found at several locations in Venezuela, and, as mentioned above in different shapes and colors.

Both species are very much favored in Europe, as they are beautiful and elegant even when not in flower. As we who live in Europe have to grow our bromeliads exclusively in greenhouses, we greatly prefer those plants which are small in size.


A recent segment of the TV series "Survival" brought to light the important role that bromeliads play in the life cycle of a rain forest. Set in the rain forests of Trinidad it showed the many bromeliads native to that area and the amazing number of creatures which live in the cups of these plants and otherwise depend on them for sustenance. The narrator made the interesting fact that without the bromeliads life in a rain forest would be utterly different.

Regional Reflections

Observations on Bromeliad Culture in the Rocky Mountains

Bromeliad enthusiasts in the Denver, Colorado, area recently organized the High Country Bromeliad Society which is affiliated with the national society. Since Denver is officially known as the Mile High City, we have here unusual growing conditions which present unique opportunities for local bromeliad growers. Besides the 5,280 ft. (1,609 meters) altitude (even above 8,000 ft.=2,438 meters in some suburbs), the dry climate and the intense solar radiation with its high ultraviolet component, provide a plant environment totally unlike the better known U.S. bromeliad centers in California, Florida, and Louisiana-Texas. It is one of the few areas in the U.S. which could approximate some of the high, dry bromeliad country in South America.

Temperatures are such in Denver that bromeliads cannot be kept outside the year round. Summer day temperatures usually are above 80°F (27°C) but often go above 90°F (32°C); night temperatures fall to 65°F (18°C) or even to 55°F (13°C). Mountain suburbs can be and usually are 10°F (5.6°C) lower. Winter temperatures are usually variable: daytime highs of 65°F (18°C) are not unusual, neither are maximum temperatures of 25°F (-4°C), and they may occur on consecutive days. Our springtime is not well defined; it begins about March but we can expect a final snow in late May or early June. Autumn is more predictable with the first frost by the middle of September. What this means is that the bromeliads can be put outdoors safely a maximum of four months out of the year but actually closer to three months to be on the safe side. So, except for these few months, bromeliads must be kept in glasshouses, at windows indoors, or under lights. Experiences with all three, and comparisons between them, have been interesting.

Many growers do place their bromeliads outdoors during the summer months with excellent results. With very few exceptions, plants must be protected from the noonday sun. (Bromeliads cannot be equated with mad dogs or Englishmen.) One of our members, coming from Chicago in July where his Streptocalyx poeppigii took all the Illinois sun it could get and seemed to beg for more, put this plant outside in a sunny spot immediately upon arriving in Denver. Within three days it was burned almost beyond recognition.

On the other hand, a few months of properly shaded outside existence seem to allow bromeliads to reach optimum development. A specimen plant of Billbergia chlorosticta bloomed out-of-doors in August and later indoors in December. This same species is a dependable bloomer during October in the Denver Botanic Gardens glasshouse. (Compare Kurt Peters' experience in California in J. Brom Soc. XXIV, 29, 1974.) Under the influence of dry summer months, bromeliads such as B. nutans or the B. chlorosticta mentioned above do not pup freely but seem to make up for it as soon as they are brought back indoors in September. Color and/or variegations become intense with just a few hours of Colorado sun. One danger in September is leaving bromeliads out too late in the season; we find some plants are extremely sensitive to cool nights long before the first frost appears. Surprisingly, some of the more hardy-looking plants seem to be the most easily affected by the cold. Specific examples have included Quesnelia marmorata, Aechmea allenii, 'Burgundy', orlandiana. Neoregelia marmorata and sarmentosa. More than a few of us have had carefully nurtured plants nipped at the leaf tips this way. Such cold sensitivity is species rather than genera dependent.

September is always a traumatic time for bromeliad enthusiasts. If outside plants have been protected successfully from the sun, their size has increased greatly but inconspicuously. And during our beautiful summer, which lulls even the most foresighted into believing that it will last forever, no plant lover can resist buying 'just one more' least once a week. So finally, before the frost, we must face reality and try to fit too many plants to too few windows or under too few light tables.

Winter tends to be dry and, with homes heated, humidities of 5-15% are common indoors on a cold day unless a humidifier is used. And at 5,000 ft. (1,524 m.) altitude, water evaporates more rapidly than at sea level. So potting mixtures that work well in other climates or at lower altitudes do poorly in Colorado. One member had plants thriving in Osmunda fiber in Syracuse, N. Y. Upon moving to Denver, they barely survived until shifted into a more terrestrial mix. Mixtures which include soil and/or peat components do best here and appear to encourage optimum root development and growth.

Many of the tender, low altitude vrieseas so common in cultivation, Vr. hieroglyphica, platynema, etc., present some difficulties at this altitude. Members who are able to grow these plants in their homes at or near sea-level have found that these generally require glasshouse conditions here. Although this may seem a disadvantage, we are always looking for high-altitude plants that the rest of the American bromeliad community must admire only in pictures.

Most winter days in Denver are sunny, but, with only 9.5 hours of daylight on December 21, plants need large windows with a southern exposure to retain full color. Many bromeliads get leggy even at windows with the best exposures. Glasshouses are one answer that is too expensive for most. Light tables work well with many species and are a practical solution at a reasonable price if the space is available indoors. We have raised many species from seed to flowering under twin 40 watt Gro-Lux fluorescent tubes supplemented with double 15 watt incandescent bulbs. Pitcairnia andreana seems to bloom year round any time these tiny plants reach maturity and Puya mirabilis flowered in June after nearly four years under the lights. Both species produced copious quantities of viable seed (75-95% germination rate). Vriesea spp. appear to do particularly well under lights and this particular spectral mix at 14 hours/day appears to bring out the very best in delicate colors in Neoregelia and Cryptanthus species.

Denverites are lucky to have the fairly new and rapidly expanding Denver Botanic Gardens which has both conservatory and 'back-up' glasshouse space. Under the present management and horticulturists, their bromeliad collection is expanding. See Journal, March-April, 1977, page 55, article by Lawrence Mason, Jr. It is interesting to compare blooming times and successes between window, light, and glasshouse cultures. Pit. andreana pups freely in the Botanic Gardens glasshouse but have yet to bloom. Nor does Puya mirabilis, although, it does pup freely which this same species does not under lights despite its successful flowering. In the glasshouse, our Colorado sun produces almost unbelievable colors in Ananas bracteatus var. striatus and Aechmea pectinata but deepens Cryptanthus spp. well post optimum coloration. The Denver Botanic Gardens has a collection of Tillandsia species which do well in their sunny humid atmosphere but this genus is most difficult indoors in our dry climate despite humidifiers.

A large and varied group of bromeliads seem to flower regularly and on time during the year despite glasshouse, window, or lights, appearing totally indifferent to the type of care they receive. Aechmea species are the best example and Vriesea species also possess their own mysterious internal time clock. We do not yet have comparative data on Neoregelia species. Neither Dyckia nor Hechtia species have bloomed for anyone under any conditions. Some others, such as Fosterella penduliflora, bloom irregularly at intervals impossible to predict and for reasons best known to them.

Since most of us have come from other states with various experiences with bromeliad culture, Colorado is indeed different and presents exciting prospects for the bromeliad enthusiast.

Richard B. Schwendinger, Lawrence Mason, Jr., Paul L. Earle, Gary Davis


An economical compost which seems to work well in a number of tests with potted bromeliads here consists of 2 parts very coarsely chopped, undecayed oak leaves, 2 parts coarse perlite, and 1 part milled sphagnum peat. Extra sand, potting soil, or plastic fertilizer may be added as needed. In potting up tall or wobbly bromeliads, I use the Japanese method with success. After firming the compost, I add a top layer of coarse 1-inch pebbles, filling in around the plant to hold it without staking or wiring.

When I use plastic pots for economy and ease of transplanting, I find it necessary to use those with several holes around the bottom of the sides. Also, it is a good idea to burn 2 to 4 holes for more air around the pot, midway up the side. (Avoid breathing fumes).

Several trials of insecticides for use in eliminating bromeliad scale in small collections have indicated the easiest method is simply to enclose the infested plant in a small room with a nearby pest strip for a few days. Other trials at the UNL botanical greenhouse here have included spraying with cygon, isotox, and malathion with no visible damage to their small collection.

It is important to warn bromeliad enthusiasts in the midwestern plains that our bright winter sun, through glass, at a sidewise angle, will burn almost any bromeliad except desert types in just a few hours each day for several days. Plants conditioned outside here in the summer, or those taken recently from sun-drenched Florida yards, will burn here behind glass unless precautions are taken. It has been suggested that part of the problem here in the plains may be the same thing which burns our pine trees, yews, etc., so badly in some winters. The snow covers the ground for days or weeks, glazes over, and acts like a cruel mirror to double the slanting, sidewise radiations from the south. Perhaps this is part of the trouble. At any rate, growers here must take precautions with south exposures.

With regard to sprays and drenches of benlate/benomyl, we have never suffered the slightest damage to plants of any sort. On the contrary, many applications have produced almost miraculous results. Even delicate moss collections, young ferns, and seedlings respond well. Any damage from nearby "benlate" spraying must have been caused by the solvent carrier or other ingredient.

G. H. Butt, Lincoln, Nebraska

If someone wants to try a little experiment on forcing blooming, he might want to try dropping a very small crystal of paradichlorobenzene (moth crystal) into the cup and observe the plant for several weeks without other treatment. Also the pineapple growers suggest that the fruit-setting hormones will also cause bloom buds to form. Meanwhile, ˝ teaspoon of calcium carbide in two quarts of water continues to do wonders.

Aechmeas are for Everyone


Right —
A. distichantha var. glaziovii


Left —
A. fendleri

Right —
A. corymbosa var. discolor
K. Williams

Right —
A. apocalyptica 'Helen Dexter'
M. W. Dexter

Left —
A. nidularioides

Right —
A. allenii

The Structure of the Bromeliad Trichome


(Continued from the last issue. Reprinted by permission of the author and Selbyana, publication of the Marie Selby Botanical Gardens.)

With the reported exception of a single species of Navia, all bromeliads examined thus far possess foliar trichomes. A few primitive pitcairnioids, some species of Navia, for example, feature simple multicelled uniseriate epidermal hairs without caps but most members of Pitcairnioideae and all bromelioids and tillandsioids produce a distinctive peltate trichome which apparently has no close counterpart in any other family.

Bromeliad "scales", as the peltate hairs are often called, fall into two structural categories. Those characterizing pitcairnioids and bromelioids have caps made up of a flat single layer of more or less randomly aligned empty cells. Tillandsioid trichome shields, although also flat and one cell thick, all exhibit a much more orderly arrangement of cells. Centermost, just over the point where the dome or upper stalk cell is connected to the underside of the tillandsioid shield, are four equal-size thick-walled empty cells which comprise the central disc. Several additional rings of empty cells, each made up of twice as many cells as the previous one, may be present. Cells of the outermost ring of the cap — those forming the wing — are more than twice the number making up the ring of cells just within. Cells of this peripheral series are usually more elongate, often much more elongate, than the central disc and ring cells.

The size and outline of the cap as well as the number of cells present vary among species. Minor variations may occur between different parts of the same leaf. Within a given species, however, trichome cap morphology is often quite distinct. In fact, the utility of trichome cap morphology as a means for plant identification, particularly for immature individuals, has not been adequately explored.

The stalks of pitcairnioid and bromelioid scales are usually uniseriate chains of one to five or more living cells. Here again, the number of stalk cells can be uniform within species, genera or groups of genera (Tomlinson, 1969). In most species stalks are located in concavities. As the base of the stalk, at its foot, two or more small cells are often apparent. Tillandsioid trichome stalks are also comprised of living cells, in this case the number present is usually three to five. The uppermost cell, the dome cell, is the largest of the series and contains a dense protoplast and a prominent nucleus. Dolzmann (1964, 1965) discovered that this cell possesses an elaborated plasmolemma and other membrane systems which he theorized are involved in the absorptive activities performed by tillandsioid trichomes. Amorphous material of an unspecified nature occupies a space between the plasma membrane and the cell wall. Fine structure should be investigated in more tillandsioid stalk cells and these results compared with similar observations on bromelioid and pitcairnioid systems.

Both the cap and stalk cells are cutinized in a pattern consistent with their absorbing function. The stalk cells are cutinized on their lateral sides and collectively produce what is, in essence, a waterproof tube. The top of the dome cell as well as the transverse walls between adjacent stalk cells and the foot cells remain uncutinized. Shield cells seem to have cuticle over much of their outer surfaces but none below. According to Mez (1904). pectic substances are abundant in the walls of cap cells but are more concentrated in some areas than in others. Central disc cells, especially the outer walls, have pectin-rich and pectin-poor layers. Ring cells may have alternately thick and thin zones in their outer walls. These may serve as hinges when the trichome changes its conformation during the process of water absorption.


Water-absorbing hairs occur on a variety of vascular plants but none are as highly refined either structurally or functionally as those of the atmospheric bromeliads. Although suggestions to the contrary have been made (Haberlandt, 1914; Dolzmann, 1964, 1965), water absorption by the more refined bromeliad scales can be plausibly described in terms of osmotic and mechanical forces alone. Considering the absence of indisputable evidence of active water uptake in any plant system, and the structure of the tillandsioid trichome, the osmomechanical mechanism presented below is currently the most acceptable hypothesis available to account for the absorptive capacities of these appendages. Early workers (see Haberlandt, 1914), who observed that plasmolysis occurred first in mesophyll cells surrounding the bases of the stalks when hypertonic solutions were applied to intact leaf surfaces (Mez, 1904), surmised that tillandsioid trichomes could absorb water.

Rather than beading up as is usually the case when water strikes a leaf surface, drops of moisture falling on the shoot of an atmospheric bromeliad quickly spread out by capillarity to form a thin uniform film. Unlike the trichome caps on many pitcairnioids and those on the leaf blades of numerous bromelioids, tillandsioid scale cap cells readily fill with water when the shoot surface is wetted. As filling occurs, the lateral walls of the four central disc cells in particular become straightened and the upper wall is forced upward as the adjacent cell cavities are expanded by water. Simultaneous with this filling and swelling, the wing of the shield is flexed downward against the leaf surface. The combined action of water expanding the lumina of the central disc and ring cells and the downward flexure of the shield margins supposedly produces a minute suction drawing more water under the cap and into the central disc cells. By reason of this mechanism, Mez (1904) applied the term "trichompompe" to the bromeliad scale.

Once the central disc cells become filled with water, moisture moves into the dome cell by osmosis and from there into the rest of the stalk to finally enter the mesophyll below. As the leaf surface dries, moisture is lost from the shield. During this process, the lateral walls of the central disc cells again collapse, bringing the central portion of the cap back to its previous position while the wings flex upward. By the time the cap cells are empty again, the central portion of the shield has collapsed back into the epidermal concavity and is again located in a position interposed between the dome cell and the environment. Because of this closure, water is prevented from leaving the plant by its route of entry. Were it not for the cap, the thin-walled stalk cells would collectively act like a wick, rapidly drawing water from the mesophyll below only to lose it by evaporation into the atmosphere through the uncutinized upper wall of the dome cell. In effect, then, the trichome of at least the atmospheric bromeliads serves as a one-way valve which brings water into the plant while preventing its departure by the same route.

Experiments performed by placing partially dehydrated leaves in water suggest that trichomes located on the midblade regions of pitcairnioid and bromelioid leaves have little or no absorbing capacity (Benzing and Burt, 1970). The absorptive capacities of bromelioid trichomes located on the leaf sheaths have not been investigated adequately. Experiments of similar design were not sufficiently refined to determine whether the scattered trichomes on the blades of mesophytic tank tillandsioids contribute appreciably to foliar uptake (Benzing and Burt, 1970). Although generally similar in structure, the upper walls of the four central disc and adjacent rings of cells of mesophytic tank species of genera such as Catopsis and Vriesea do tend to be much thinner than those of atmospheric tillandsias. The former also have much narrower wings. Whether these variations in cap structure are of sufficient magnitude to prevent or impair water uptake by the mechanism described above is unknown. For whatever reason, when placed in water leaves of tank tillandsioids rehydrate very slowly compared to those from atmospherics. Also unanswered is the question of the ability of a bromeliad scale to absorb water from the gaseous phase. Preliminary investigations of this possibility do not support claims that such an ability is well developed (Duchartre, 1868; Benzing and Dahle, 1971).


The most direct evidence of trichome involvement in nutrient uptake among certain species of Bromeliaceae has accrued from experiments employing labeled amino acids and microautoradiographic technique (Benzing et al., unpublished manuscript). These analyses were carried out by placing solutions containing small quantities of tritiated leucine or glycine on intact leaf surfaces of bromeliads selected to reflect both ecological and taxonomic diversity within the family. The results of these experiments can be summarized as follows.

After pulses of 3H-glycine and 3H-leucine ranging in duration from 2 to 180 min had been applied to various specimens and the sectioned tissues had been exposed to a photographic emulsion, the trichome stalk cells of all tillandsioids examined, including those which had been freeze-sectioned rather than paraffin-embedded before sectioning to avoid moving the label, were found to contain substantial quantities of tritium. Leaf segments from both the blade and the sheath of tank tillandsioids were tested. Adjacent epidermal cells and the empty trichome cap cells bore little or no label. Subsequent to identical treatments and processing, the stalk cells of Pitcairnia undulata, P. macrochlamys and Bromelia balansae, which are soil-rooted species lacking tank leaves (Type I and II), as well as those on the blades of the tank species Aechmea bracteata, Billbergia pyramidalis and Neoregelia spectabilis (Type III) exhibited very little, if any, labeling. Stalk cells from trichomes located on the sheathes of these three tank bromelioids accumulated some label but far less during 0.5 h treatments than any tillandsioid tested. These data parallel the finding of experiments reporting substantial accumulations of radiocalcium and radiozinc in xeric (atmospheric) Tillandsia leaves from solutions placed on the leaf surface containing these inorganic nutrients and lower rates of uptake in all less specialized species investigated (Benzing and Burt, 1970).

Additional aspects of the behavior of the tillandsioid trichome in foliar uptake were noted in these experiments. Guzmania monostachia leaf blade tissue pulse-labeled at 2, 10, 20 and 30 min with 3H-leucine demonstrated that, as expected, the dome cell is the initial site of accumulation and that the stalk cells beneath this distal one — and therefore farther removed from the leaf surface — as well as the foot and adjacent mesophyll cells, become labeled only after longer exposures. Apparently solutes are absorbed and move along the same pathway traversed by water molecules as they enter the shoot. Observations on Tillandsia usneoides leaves treated with 3H-glycine for 3 h indicate a preferential localization of this amino acid within the chloroplasts of mesophyll cells. Treatments of heat-killed leaves of Guzmania monostachia and Tillandsia usneoides suggest that active processes and living stalk cell protoplasts are required for the accumulation of these amino acids by the trichome. After treatment of 0.5 h in 3H-leucine or 3H-glycine, the trichome stalk cells of boiled leaves contained almost no label. Leaves treated with 10-4 M KCN for 0.5 h prior to and during treatment had accumulated approximately as much label as uninhibited controls but 3H-glycine had not been preferentially localized within the chloroplasts.

The occurrence of tritiated material in the stalk cells of these trichomes in the absence of similar quantities of label in the rest of the foliar epidermis after the leaf surface is flooded with solutions containing tritiated leucine or glycine does not represent direct proof that these organs serve as the major conduits for the passage of either of these molecules or any others into the leaf interior. However, these observations do at least demonstrate that the stalk cells of tillandsioid trichomes and, to a lesser extent, those from the leaf sheath zones of those tank bromelioids tested, can rapidly absorb and immobilize solutes from solutions placed on the leaf surface even though they are shielded from the external environment by a cap of nonliving, and in some cases, heavily cutinized cells. Trichomes from the blades of tank-forming species of subfamily Bromelioideae and those from the leaves of primitive terrestrial Pitcairnia resemble the unspecialized epidermal cells adjacent to the trichomes borne by all species tested in that they do not exhibit comparable capacities to immobilize these two solutes from the leaf surface environment.

Longer term experiments designed to evaluate the rates of accumulation of several macronutrients by derooted but otherwise intact specimens of field-collected atmospheric Tillandsia circinnata demonstrated that this species possesses remarkable abilities to absorb inorganic nutrients when provided the opportunity to do so (Benzing. 1973). In this case, daily brief immersions in an enriched nutrient solution brought about 20-fold increases in total phosphorus content within 120 days. Potassium and nitrogen levels also increased substantially but to a lesser extent. It is assumed but not proven that these accumulations were accomplished by the foliar trichomes.

All the experiments cited here suggest that the foliar trichome of Bromeliaceae has evolved to a state in its most ecologically specialized members — for example, Spanish moss-wherein this organ is capable of providing, in the absence of absorptive roots, the uptake capacities required of nonimpounding xerophytic bromeliads that must scavenge nutrients from the dilute solutions which only infrequently and then briefly come in contact with the plant body. Trichomes located on the leaf sheath surfaces of tank bromelioids, although apparently less absorptive in terms of uptake rates, may still function as the primary points of foliar accumulation since they remain in contact with solutions containing nutrients as long as the tanks impound moisture. As such, they would not require uptake capacities equivalent to those possessed by species adapted to very dry habitats.


In addition to performing indispensable services as absorbing organs, the trichomes on at least the atmospheric bromeliads produce conditions that affect success in certain habitats for reasons involving factors other than mineral or water balance. At least two qualities of the trichome cover are now known to oblige atmospheric species to reside in exposed dry environments and to fail in deep shade and excess humidity. Because the stomates are located beneath a layer of broadly expanded wettable trichome caps and gases diffuse much more slowly through liquid media than through air, the thin film of water held against the shoot surfaces of atmospherics by their moistened scales severely curtails gas exchange between plant and environment. Experiments performed on several bromeliads have demonstrated that CO2 exchange can be abruptly reduced to a few percent when the shoot surfaces of these species are wetted. With subsequent drying, normal exchange rates resume (Benzing and Renfrow, 1971b). Identical treatments of mesophytic tank tillandsioids (Type III) with a sparse trichome cover revealed that moistened leaves in these species continue to evolve CO2 at the rates exhibited prior to wetting.

When filled with air, tillandsioid trichome caps are also highly reflective: they thereby reduce the amount of light available for photosynthesis. Depending on the wavelength, desert populations of Tillandsia fasciculata reflect between 42 and 47% of the visible light impinging on their adaxial leaf surfaces while similar surfaces of mesophytic tank-producing Catopsis nutans and Guzmania lingulata reflect no more than 28% of the light provided (Benzing and Renfrow, 1971a). Although CAM plants generally have high light requirements, the shade intolerance shown by atmospherics must be partly attributable to the light reflective and possibly light absorptive qualities of their trichome cover. These experimental findings offer a plausible explanation for the absence of atmospheric bromeliads in many wet, poorly aerated or dark environments.

Bromeliad trichomes also reflect infrared radiation and thereby reduce the heat load of leaves exposed to sunlight. This type of heat dissipation may be very important to succulent bromeliads growing in exposed conditions in still air since they have reduced capacities for both convectional and evaporative cooling. Experiments by the author on Tillandsia circinnata, (Unpublished data) a compact-bodied atmospheric, illustrated that significant temperature increases developed when specimens with leaves fitted with small thermocouple probes were placed in sunlight after their trichome caps had been removed with a razor blade or rendered transparent by applying a thin layer of mineral oil. Specifically, in a representative case, temperatures were elevated up to 7.5°C above that of the surrounding air in full sunlight when caps were present and dry but leaf temperatures rose 10.4°C above ambient subsequent to an application of mineral oil. These results approximate those of Baumert (1907) who reported that illuminated Tillandsia flexuosa leaves were up to 23.8% cooler than those with the caps removed.

Bromeliad scales probably also serve to reduce transpiration by increasing boundary layer thickness. This hypothesis is supported by several aspects of leaf anatomy. For example, the individual pitcairnioid scale may be situated in a minute concavity with adjacent stomates encircling the stalk within the area of the chamber covered by its shield (Robinson, 1969). Many other bromeliads produce both their stomates and scales within grooves which extend the entire length of the leaf blade. Finally, many pitcairnias, Cryptanthus species and others produce confluent layers of trichome caps on the abaxial leaf surface while the astomatous adaxial side is glabrous.

An interesting but somewhat puzzling trend in stomate-to-scale ratio exists in Bromeliaceae. Pitcairnioids, at least the species examined (Tomlinson, 1969), have an average of 13.6 stomates per foliar scale. Bromelioids investigated exhibit a mean ratio of 3.2 to 1 while Tillandsioideae as a whole shows a 1.5 to 1 relationship. Lowest ratios were noted among 14 atmospherics where the average was only 0.5 to 1. One species, the highly reduced Tillandsia bryoides, supposedly has no stomates at all.

Since a confluent layer of shields can be produced with a few trichomes topped by broad caps and is in fact produced in this manner by many pitcairnioids and bromelioids, the low ratios encountered in atmospherics may be attributable to specific requirements for high trichome density. In this instance, the indumentum must perform the additional task of water and nutrient absorption.

Benzing and Burt (1970) have already demonstrated that foliar absorptive capacity in Bromeliaceae is not directly correlated with trichome frequency but is related to the area of the leaf surface occupied by living stalk cells. Species with pronounced uptake capacities have up to 5.0% of their leaf surfaces occupied by trichome stalks whereas among pitcairnioids, bromelioids and mesic tillandsioids tested, the figure for this feature may be about 1.0% but is usually much less. Mean trichome stalk diameter ranges from 7.7-53.2 u among the 20 bromeliads examined. Those of tillandsioids, whether tank or atmospheric type, are by far the largest. Trichome density is greatest in atmospherics and lowest in mesic tank tillandsioids. Even though the dome cells of tillandsioid trichomes are much larger than the upper stalk cells of pitcairnioid and bromelioid scales, in order to achieve the high percentage of leaf surface occupied by dome cells atmospherics must produce high trichome densities — often higher, as it turns out, than those encountered in Pitcairnioideae and Bromelioideae. To more precisely understand the significance of stomate-to-scale relationships and other peculiarities of leaf anatomy, further analyses should be carried out to determine stomate and trichome frequencies and their spatial and numerical relationships, moisture exchange phenomena (both uptake and transpiration), and mineral uptake capacities, and the relationships of these characteristics to the ecology of diverse species.

Among families with representatives in the driest and most nutrient-deficient portions of the epiphytic biotope, only Bromeliaceae has substantially reduced or eliminated its dependence on a root system as the primary site of nutrient and moisture uptake. Just why a foliar hair has developed to such a specialized degree as an organ of absorption in this family alone is difficult to explain. Perhaps the ancestral bromeliad stock was somehow preadapted to evolve and rely heavily on a foliar hair with absorptive capacity.

If foliar hairs produced by very early bromeliad stock resembled those found now in primitive elements of Pitcairnioideae, one feature of this type of trichome, a basal cell or series of cells with persistent protoplasts, would have provided the necessary basis for the perfection of the absorptive role this organ now plays in Bromelioideae and Tillandsioideae. Certainly a trichome with a living basal cell or cells embedded below the level of the surrounding unspecialized epidermal cells would be better positioned and functionally disposed to achieve absorptive capacities requiring osmotic and active mechanisms than a more superficially located appendage made up of dead cells. Later, once the cap appeared, living stalk cells no longer would need thick cutinized walls on all exposed sides but could develop a specialized absorptive surface directly under the protective shield. What selective advantages, other than those associated with water economy if any, may have accounted for the evolution of the peltate trichome in its nonabsorptive stage of refinement are not apparent at this time. Also unclear are the reasons why the nonabsorptive hairs of Pitcairnioideae and Bromelioideae have living stalk cells.

In any case, bromeliad trichomes are highly varied both structurally and functionally. The structural basis for the absorptive action and the relationship of this capability to habitat preferences have been outlined already. Other structural variables with less defined ecological concomitants are the size and outline of the trichome shield, especially in Tillandsioideae. In this subfamily both the number of ring cell series and the width and shape of the wing vary in accordance with the ecological category and habitat preference of the species concerned. Atmospherics routinely bear trichomes with caps composed of two or three series of ring cells and wide irregularly shaped wings whereas 7 of 8 mesophytic tank-forming tillandsioids examined by this author produce shields with but one series of ring cells and a narrow, nearly circular wing. Scale frequency is much lower in tank forms as well and this, along with the reduced shield, act to diminish reflectance and enhance light reception in Type III tillandsioids. Recall that Pittendrigh's shade-tolerant group in Trinidad is comprised of tank tillandsioids exclusively and that these species have low light compensation and saturation points.

Among atmospherics, shield outline and length seem to correlate with environmental humidity. Species with the most attenuated shield such as Tillandsia plumosa often occur in cloud forests where their shoots are frequently moistened with rain or heavy fog. Rather than serving as dew-collecting points, as some have suggested, the projecting, sometimes hairlike shields may serve a more important role as sites for evaporating the capillary water remaining on the epidermis before the next episode of precipitation rewets the shoot surface. Perhaps also significant are the filiform leaves of such species. At the opposite extreme in very dry environments where suffocation would never be a problem, species such as T. rigida bear scales whose shields are nearly round in outline and are closely appressed to the epidermal surface. The warty texture of the outer walls of the shield cells may increase light scattering. Species such as T. recurvata with tolerances for high and low humidity should be examined to determine whether trichome shield morphology and rates of surface drying vary together and with the humidity of the home ranges of the populations chosen for study.

Suggestions that atmospherics arose in neotenous fashion from tank tillandsioids are in part based on the assumption that seedling stages of the latter are preadapted by virtue of drought tolerance and nutritional mode to exist on drier sites than tank adults could tolerate if they had no impoundments. This hypothesis should be tested by examining the morphology and physiology of tank seedlings. Neoteny (or phylogenetic recapitulation) would be indicated if tank seedlings were shown to possess features such as CAM and trichome densities, shield morphologies and stomate-to-scale ratios more characteristic of atmospheric relatives than their own adult stages.

These questions and others mentioned in previous sections of this paper, plus many more, await the attention of persons interested in bromeliads and their adaptive biology and evolution. One can go one step further by declaring that the bromeliad trichome merits the interest of anyone seeking a remarkable example of how the total biology of a taxonomically diverse and ecologically varied group of higher plants is closely linked to the structure and function of its epidermal hairs.

Oberlin College, Ohio


Baumeret, K. 1907. Experimentelle Untersuchungen uber lichtschutzeinrichtungen an grunen Blattern. Diss. Erlangen; see Beitr. biol. Pfl. 9:38-162 (1904-9).

Benzing, D. H. 1973. The monocotyledons: their evolution and comparative biology. I. Mineral nutrition and related phenomena in Bromeliaceae and Orchidaceae. The Quarterly Review of Biology 48 (2):277-290.

Benzing, D. H. and K. M. Burt. 1970. Foliar permeability among twenty species of the Bromeliaceae. Bull. Torrey Bot. Club 97:269-279.

Benzing, D. H. and C. Dahle. 1971. The vegetative morphology, habitat preference and water balance mechanisms of the bromeliad Tillandsia ionantha Planch. Am. Mid. Natur. 85:11-21.

Benzing, D. H. and K. Henderson, B. Kessel and J. Sulak. The absorptive capacities of bromeliad trichomes. Unpublished manuscript.

Benzing, D. H. and A. Renfrow. 1971a. The significance of photosynthetic efficiency to habitat preference and phylogeny among Tillandsioid bromeliads. Bot. Gaz. 132 (1):19-30.

_________________________1971b. Significance of the patterns of CO2 exchange to the ecology and phylogeny of the Tillandsioideae (Bromeliaceae). Bull. Torrey Bot. Club 98:322-327.

_________________________1971c. The biology of the atmospheric bromeliad Tillandsia circinnata Schlecht. I. The nutrient status of populations in South Florida. Amer. J. Bot. 58 (9):867-873.

_________________________1974a. The mineral nutrition of Bromeliaceae. Bot. Gaz. 135:281-288.

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Notes from Australia

Variegated Neoregelia concentrica

South Australia, climatically (as we have often been told to the point of boredom) is the driest state in the driest continent. However, this must be looked at in the light of varying rainfall areas within the state. Here on the Adelaide plains it is a fairly consistent 24 inches a year, mainly winter rain April through October. That means, of course, we can expect rain in the autumn from Easter time on through to late spring in October.

The three main months of summer, from December until March, are usually very dry, occasionally very humid, and with hot spells with temperatures during the day often going into the 90°F and sometimes well over 100°F. Winter time can see ground frosts and sometimes snow in the Adelaide Hills over 2,000 feet elevation. Usually day temperatures during winter are between 46°F. and 70°F.

I have no greenhouse; all my bromeliads grow either outside in pots or under a plastic shade-cloth house (52% shade) with my cymbidiums, several cattleyas, and some native orchids. My bromeliads are varied in size and species. I have had very good results from almost all plants; that is, flowers have appeared and new vegetative growth has been made. In fact 10-inch and 12-inch pots are now splitting, and I have the colossal task of dividing and repotting. I am using and shall continue to use the UCLA cymbidium mix as a base potting mixture, plus additional fertilizers, sharp sand, or whatever else I think might be needed.

Among the bromeliads which have bloomed the past summer are Aechmea fasciata, Billbergia vittata × B. pyramidalis, Neoregelia spectabilis, Nidularium burchellii, Aechmea lueddemanniana, Puya mirabilis, Aechmea 'Foster's Favorite,' and Aechmea recurvata.

J. A. Eastwood, Albert Park

Several years ago, my Neoregelia concentrica had a mutation which has proved to be a very beautiful variegated form. To date it has had only one offshoot, but this has remained variegated. The plant seems to be slightly smaller and less compact than normal concentrica. I do not know of any other plants in Australia, and I would like to know if this plant is common in America. We are led to believe that this is an Australian sport.

John L. Nicol, Melbourne

Costa Rica, the home of Aechmea mariae-reginae, is situated in latitude 10° North, whereas Sydney, Australia, is about 34° south, yet this bromeliad thrives happily outdoors here. I have had a single plant growing for the past seven years.

It has been in a two-gallon black plastic container during most of this time in a potting mix of roughly three quarters tree fern fiber and one quarter sharp river sand. The flower head, a cross between a corn cob and a pineapple in form, is creamy white, sheathed by pink bracts about 20 cm. long, which peeled away from the inflorescence to hang down below it. Unfortunately a few dry, hot windy days resulted in the bracts becoming sunburnt, which detracted from the appearance. Blue flowers started to show from the inflorescence in rings from the bottom upwards, the lower ones rapidly turning to pink as the higher flowering continued to occur. In all, it took about two weeks to come out fully and then quickly faded. It was a very rewarding sight and well worth all the years of waiting to see the bloom.

F. A. Allen, Lindfield, N. S. W.

From the Queensland garden of Grace Goode.


Right —
Aechmea angustifolia with border of Neoregelia carolinae in the background.

Left —
Vriesea regina, over 7 feet in height, towers over a planting of bromeliads.

Neoregelia 'Green Apple'



I have been propagating this plant for three years and find it to be an exceptional hybrid. The late Ralph Davis made numerous hybrids and occasionally he was dissatisfied with his results, and this was one of the plants he discarded. Fortunately, a curious individual retrieved the seedlings and grew them to maturity.

In Miami, it remained insignificant, being green and lacking any outstanding coloration. Subsequently it was labeled Neoregelia 'Green Apple'. When I received the plant I placed it in my growing medium and subjected it to bright light. I was extremely pleased with the results. Although the parentage is unknown, this is a quality plant and a tribute to Ralph Davis.

Lithia, Florida

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