1-1.5 mm in diameter towards throat, glabrous, white below becoming petunia-purple above, corolla-lobes 0.8 mm long, 0.7 mm wide, shortly papillate outside towards apex, glabrous inside, dilated at apex, apex acute. Filaments very considerably swan-necked in corolla-tube; anther-append- ages at least twice as long as wide, apex acute. Style glabrous, barely enlarged towards base; style-arms maroon, appendages of style-arms with crown of long papillae. Ackenes 3--1 mm long, 0.5-1 mm in diameter, c. 8-10-ribbed, the ribs setuliferous, the body glabrous (achenes completely glabrous according to Turczanimov); pappus-setae white, (&)%lo mm long, barbellate, easily detached.

DISTRIBUTION. Columbia, Ecuador and Venezuela, high-altitude rocky, grassy or marshy paramos; altitude 3,00&4,500 m.

REFERENCES

Jeffrey, C. (ined.). The Tribe Senecioneae (Compositae) in the Mascarene Islands. Kew Bull.

Sandwith, N. Y. (1925). Humboldt and Bonpland’s itinerary in Vene- zuela. Kew Bull. Misc. InJ 1925: 295-310. (Reprinted in Stearn, W. T. (1968), see infa, pp. 69-79.)

(1926). Humboldt and Bonpland’s itinerary in Ecuador and Peru. Kew Bull. Misc. InJ 1926: 181-190. (Reprinted in Stearn, W. T. (1968), see infa, pp. 87-94.)

Sprague, T. A. (1926). Humboldt and Bonpland’s itinerary in Colombia. Kew Bull. M i x . InJ 1926: 23-30. (Reprinted in Stearn, W. T. (1968), see infra, pp. 82-86.)

Stearn, W. T. (1968). Humboldt and Bonpland’s Travels in America in Stearn, W. T. (ed.). Humboldt, Bonpland, Kunth and Tropical Ameri- can Botany (A miscellany on the ‘Nova Genera et Species Plantarum’) 41-48. Cramer, Stuttgart.

Weddell, H. A. (1856). Ckloris andina 1: 124-125. Bertrand, Paris.

164. EPIDENDRUM ILENSE 0 rch idaceae

Sarah Robbins and Sandra Bell

Epidendrum L. is one of the largest and most widely distributed of orchid genera in the tropical Americas. The number of species is estimated to be in excess of 1,000, distributed from North Carolina to Argentina. Despite the popularity of this genus, only a few species are at all common in cultivation.

Epidendrum ilense, one of the most striking species in the genus, has recently begun to appear in collections. Although horticulturally

5

desirable, i t is on the verge of extinction in the wild and a concerted effort has been made to save it by propagating cultivated plants.

Epidendrum ilense is named for the Mountanas de Ila in Ecuador, where it was discovered in 1976 by Dr Calaway Dodson. The Montanas de Ila are a range of hills on the western side of the Andes, inhabited by a surprisingly large number of endemic species. While on a collecting trip there, Dr Dodson and his companions surveyed a patch of recently cut forest. After three hours of careful searching they found 62 orchid species. One of these species was a new Epidendrum, and was later described by Dr Dodson (1977) in Selbyana as E. ilense. Several plants of this species were taken to the Marie Selby Botanical Gardens. Here the plants were selfed, but no viable seed was produced.

A few months after the initial discovery, Dr Dodson returned to the original patch offorest to find that it had been felled and was now a cornfield. Much of the surrounding forest had also been cut, leaving little of the original forest type in the area. In the succeeding months the whole of the Montanas de Ila region was searched for E. ilense without success. The orchid had apparently become extinct in the wild.

It seemed that the only existing plants of E. dense were those few held in the Marie Selby collection. Further attempts were made at selfing or sib-crossing the plants, but these were unsuccessful. Under the assumption that the species might be self-sterile, the only hope for maintaining it was tissue culture. This became one of the first species to be propagated successfully at the Eric Young Microprop- agation Centre a t Marie Selby. Fortunately, sometime after an explant was established in vitro, a seed-capsule produced viable seed. The seedlings that were successfully raised from this pod introduced some genetic diversity in the cultivated material. Plants were distributed to botanic gardens and scientific institutes world-wide, and were also sent to every orchid grower willing to donate $100 to either the American Orchid Society or the Marie Selby Botanical Gardens. Epidendrum ilense is now widely distributed among collections. Some plants have been replanted at the Rio Palenque Reserve in Ecuador which is not far from the Montanas de Ila, where it is hoped that they will become established.

Epidendrum ilense is similar to E. anceps Jacq. in its habit. It also has features of the Pleuranthium group with short subcapitate inflorescen- ces being produced from the older stem nodes. The species can easily

6

Epidendrurn ilense

Plate 164

HELEN HAYWOOD

be distinguished by the long-fimbriate margin of the lip and the pale green to ivory coloured flowers.

Only one artificial hybrid grex of Epidendrum ilense has so far been recorded: Epidendrum Plastic Doll (E . pseudoepidendrum x E . ilense) registered by T. Matsuda (see Orchid Review, 1986). This is an attractive plant and suggests that E. ilense might be used to advantage in hybridizing with other taxa.

CULTIVATION. Epidendrum ilense is a rewarding species to grow and adapts readily to cultivation. At Kew it has been grown in a number of different environments but grows best in a fairly well-shaded house in which fluctuations in humidity are discouraged and a uniform relative humidity of 85 to 90 per cent is maintained. The temperature is maintained at a minimum of 16°C at night and 21°C during the day.

This species is grown in pots rather than tied on to bark and a mature plant is allocated an 8” diameter clay pot. This is well crocked and filled with a bark-based epiphyte compost. Epidendrum ilense, in common with many other orchids, will not tolerate being potted deeply and is planted with the top of the rhizome visible on the surface of the compost. Secure staking is needed until the plant becomes established.

Growth seems to occur throughout the year and plants are fed with a dilute foliar and root feed every fortnight when they are in active growth. Flowers are produced from the tips ofmature growths and sporadically from the internodes of old leafless canes. From April until November a mature plant of this species is rarely flowerless.

Epidendrum ilense Dodson in Selbyana 2( 1): 51 (1977) and in Amer. Orch. SOC. Bull. 50: 1083-1086 (1981). Type: Ecuador, Centinela, 12 km east of Patrica Pilar, 30 May 1976, Dodson 6094 (SEL).

DESCRIPTION. Epiphytic her6 up to 80 cm tall. Stem cane-like, compressed, leafy except at the base, entirely concealed by leaf-sheaths. Roots greenish white, up to 15 cm long, often branched. Leaves few to numerous, distichous, narrowly elliptic, 11-18 cm long, 2-5 cm wide. Inflorescence terminal or lateral, simple or branching; if terminal, elongate, arching to pendent, enveloped by several distichous compressed sheaths, each branch short, subcapitate, with 3-5 flowers; if lateral, raceme short, subcapitate, produced from the stem nbdes. Flowers pale green to white, of medium size for the genus. Dorsal sepal concave, obovate, 12-1 5 mm long, 5-6 mm wide. Lateral sepals obovate, oblique, slightly broader than the dorsal sepal,

7

12-15 mm long, 7 mm wide. Petals linear-obovate, 12-15 mm long, 2-3 mm wide. Lip adnate to the column in the basal part; lamina cuneate, 20- 25 mm long, 30-35 mm wide, the apical margin with a fimbriate fringe up to 10 mm long; calli 3, ridge-like, running from the apex of the column to the apical third of the lamina, Column straight, dilated above, 12 mm long, 4 mm wide across the apex. Pollinia in 2 pairs, ovoid.

Epidendrum ilense. A, bract; B, petal; C, lateral sepal; D, dorsal sepal; E, lip and column, side view; F, anther cap; G, pollinia; H, column; J, lip. Drawn by Helen Haywood.

DISTRIBUTION. Ecuador: Montanas de Ila; altitude G. 540 m.

165. IRIS TENAX Iridaceae

Brian Mathew

This attractive iris from the western United States belongs to the rhizomatous beardless group of species known laboriously as subgenus Limniris (Tausch) Spach section Limniris series Califrnicae (Diels) Lawrence, a rather natural group which is confined to the

8