VENEZUELA'S ORCHIDS AND TEPUIS by Brian Milligan
A recent National Geographic TV program on Venezuela's tepuis has reminded me of the late G.C.K. (Stalky) Dunsterville and his wife Elinor (Nora), and their search for orchids in Venezuela over a period of almost forty years. Bora and educated in England, Dunsterville spent most of his working life abroad in the employ of the Shell Oil Company. Although (perhaps because) his first name was Galfrid, he was usually known as 'Stalky'. In 1947 Shell Oil transferred the Dunstervilles to Venezuela. After Stalky's retirement in 1959, the Dunstervilles stayed on in Caracas for another twenty years.
Shortly after their arrival in Venezuela the Dunstervilles developed an interest in the country's native orchids, which soon became a passion. They spent most weekends in search of orchids, from which Stalky made exquisite pen-and-ink drawings as an aid to their identification. He sent these drawings first to the taxonomist Victor Summerhayes (Kew) and then (after Summerhayes' death) to Leslie Garay (Toronto and Harvard). Over a period of thirty years Dunsterville and Garay identified 1050 different Venezuelan orchid species (from an estimated total of 1200). Dunsterville's drawings and Garay's descriptions were progressively published in the magnificent 5-volume series of Venezuelan Orchids Illustrated. In addition Dunsterville published about 250 articles describing the various orchids that he and his wife found in the course of their expeditions.
The Dunstervilles' expeditions covered much of Venezuela, from tropical lowland forest to cold, alpine mountaintops. Which eventually brings us to their expeditions to several of Venezuela's unique tepuis, which are isolated sandstone tabletop mountains that protrude up to a thousand metres above the surrounding jungle floor. There are at least thirty tepuis in Venezuela, the most well known being Auyantepui and Roraima.
Auyantepui is one of the largest, covering an area of about 300 square miles and surrounded almost completely by sheer cliffs hundreds of metres high. It is home to the highest waterfall in the world, Angel Falls. The falls are named after Jimmy Angel, who crash-landed his plane on the summit near the source of the falls in 1937, and was lucky to find his way back safely to civilisation. Roraima, first climbed in 1885, was the setting for Sir Arthur Conan Doyle's Lost World, where his fictional heroes had hair-raising adventures eluding the local dinosaurs!
The Dunstervilles spent three weeks on Auyantepui in 1964, climbing to the top (altitude over 2000 m) by the only known route near the southern end. A team of native Indian porters carried the necessary camping gear and provisions. Because of time limits and the difficult, rocky terrain, they were able to explore only a very small part of the extensive tabletop area. They found that most of the orchids were terrestrial or lithophytic, although some small epiphytes grew on locally dense, dwarf forests. Despite the hot days, cold nights, torrential rain and high winds, the orchids grew so prolifically that Dunsterville estimated that Auyantepui was home to over 50 million orchid plants! Some of the major species were quite large. Eriopsis biloba had flower spikes ranging from 60 cm to 1.2 m tall, while Oncidium nigratum had branched inflorescences up to 1.8 m tall! Other common orchids were Epidendrum nocturnum, Oncidium warmingii and Zygopetalum (syn. Mendoncella) burkei.
A summary of the Dunstervilles' search for orchids during their long sojourn in Venezuela may be found in Orchid Hunting in the Lost World (And Elsewhere in Venezuela), published by the American Orchid Society shortly after Dunsterville's death in 1988.