Dr. Calaway Dodson of the University of Miami, the leading investigator in the field today, described to me the brilliantly colored bees that pollenate highly fragrant orchids of the genera Stanhopea and Catasetum.
“The Euglossine bees that pollenate these orchids are iridescent green, gold, and old rose. We calcu¬late that about 2,000 species of orchids are pollen¬ted by these bees.
“Like most scientists, I am so engrossed in my work that even my honeymoon was a field trip. When I married in Ecuador in 1960, I took my wife to an old cacao plantation where the trees were covered with orchids. I found a budding plant of Stanhopea tricornis and took it back to the hotel to keep overnight until the buds opened. Then we would hang it where the bees could find it.
“We kept the plant in the room beside ours, where my assistants were staying. Next morning I got up early and went to wake them. The scent of my wife’s perfume was very strong in their room, but she had not been there. Then I saw that the orchid flowers had opened. I returned to our room and sniffed my wife’s perfume bottle. The label said Diorissimo, but the scent was that of Stanhopea tricornis.
“Well, I dipped bits of blotting paper in the perfume, and, do you know, the bees came to them in preference to the flowers. I kept scattering Diorissimo around, but my wife was very put out when I used up all her perfume to attract ‘some stupid bees.’ “I told Dr. Dodson that on a jungle river in Colombia I had seen green Catasetum orchids that had such wonderful fragrance that any perfumer who penetrated the secret of that scent could make a small fortune. Even the name was ready to hand: Green Orchid.
“We probably know what it is,” said Dr. Dodson. “We have analyzed many orchid scents, and of the 56 compounds so far dis¬covered, we have identified 32. For example, one substance our honeymoon orchid and Christian Dior’s perfume share is benzyl acetate. Another compound that attracts bees to some orchids is cineole, also found in eucalyptus leaves and Vicks VapoRub.
“When we knew that, I was able to dip blotting paper in the pure stuff and attract a hundred times more bees than with the flower itself. My wife was happy, because after that I let her perfume bottles alone.
“The other day a man from Paris who does research for the big perfumers came to learn about the compounds that make some orchids smell so good. So your Green Orchid may yet be on the market.”Insect-pollenated orchids display the most ingenious and bizarre adaptations to ensure their survival.The white Christmas Star orchid from Madagascar, Angraecum sesquipedale, has an exceedingly long spur, or nectary, hanging down from the flower lip. Despite the name (sesquipedale means a “foot and a half”) the spur is about a foot long, but the “there may be roughly a thousand plants of Oncidium mygreenandgold, and each plant may have a hundred small flowers on it. Yet of these thou¬sands of flowers rarely do we find more than five seed pods produced. This tells us that pollenation is a rare occurrence, yet since one seed pod contains thousands of seeds, this is enough to keep the population going.”
On vanilla plantations in Tahiti I used to watch girls going from flower to flower, lift¬ing the little tongue on the flower column with a pointed stick, and pressing anther and stigma together. They called it “marrying the orchid,” and an assiduous matchmaker could …ail pollenate 2,500 flowers in one day. Nature would probably have fecundated no more than half a dozen.
Rudyard Kipling might have been speaking of orchids when he wrote: Still the world is wondrous large—seven seas from marge to marge…. And the wildest dreams of Kew are the facts of Khatmandu. Kipling underestimated Kew, the Royal Botanic Gardens nectar fills only an inch and a half at the ex¬treme end (below). More than a hundred years ago Charles Darwin speculated on the nature of the insect that could reach the nectar and pollenate the flower:
“… In Madagascar there must be moths with proboscides capable of extension to a length of between ten and eleven inches! This belief of mine has been ridiculed by some entomologists….”
Forty years later a moth exactly fulfilling Darwin’s prediction was found in Madagascar and named Xanthopan morgani praedicta. No one yet has observed the appropriately named praedicta fertilizing the beautiful Christmas Star orchid, which is not strange, as it presumably does so in the dark. But the orchid is there, the moth is there, and doubt¬less they find each other in the soft tropical night of the Great Red Island.
Some orchids are as prodigal of seeds as cod are of eggs. Darwin calculated that if every seed produced by a small European orchid germinated, the offspring would cover the entire land mass of the earth in three generations. He was dealing with an orchid that,by his count, had only 6,200 seeds in each of some 30 capsules. I know of a Venezuelan orchid that produces only one or two capsules, but each contains four million seeds.
Darwin wrote: “What checks the unlimited multiplication of the Orchidae throughout the world we do not know.”Dr. Calaway Dodson gave me at least part of the answer: Extremely few actually get pollenated.”In an acre of forest,” Dr. Dodson said,near London. Here grow specimens from every orchidaceous region on earth, but especially from Kat¬mandu and other valleys of the Himalayas, for Kew specializes in Asian and African orchids, leaving to Harvard University’s herbarium the emphasis on orchids of the New World.
Kew, the most famous botanical garden in the world, was started in 1759 when Augusta, Princess of Wales, set aside nine acres of land beside the Thames above London. To¬day it maintains a herbarium of preserved specimens of many thousands of orchids. Mr. Peter F. Hunt, who is in charge of the Orchid Herbarium at Kew, told me:
“At the last count—as of the first of November 1970—we accepted about 18,000 species as occurring in the world. The stud books record about 35,000 hybrids; by these counts, we might say that there are twice as many man-made orchids as natural species. But no two orchidologists agree on how many natural species there are in the world.
“The question is: What is a species? As someone aptly said, nature made only populations; it is man who groups plants and animals into artificial categories of his own invention: species, genera, and families. But what are the absolute distinguishing marks of a species? When does one feature of a flower make it a variety or a different species? “Today the orchid world is divided into what we call the qumpers’ and the ‘splitters’ —those who want to reduce the mass of de-scribed orchids to fewer species, and those who try to subdivide them still further.”
Some time later I asked Dr. Leslie Garay, curator of the Orchid Herbarium of Oakes Ames at Harvard (page 491), about this: “We, too, recognize more than 18,000 spe¬cies officially, but I think that’s too conservative,” he said. “At home I have a personal card file listing more than 60,000 orchids that someone has described sometime, somewhere.
And if you search the literature, you will find some 140,000 names actually recorded. Obviously, many of these are synonyms.
“You see, the splitters would regard a blond man and a black man as two different species. The lumpers, on the other hand (and today they are in ascendancy), recognize that plants are like men in that there are wide differences among them. The trend now is to regard a plant population, not a single specimen, as the basic biological entity. That is why I estimate that there must be some 20 to 35 thousand species of orchids so far known.”