Pleiones of Sikkim-Himalayas

Naresh Swami

Pleione composes one of the most attractive orchids from the Sikkim-Himalayan region. Its habitat ranges between altitude 750 to 3600 m, within the tropical hot forests to the cool alpine valleys. Besides this genus the other growing under such altitudinal variation is those from the genus Habenaria only. The genus was established by David Don in the year 1825, prior to which it was under the genus . Mostly the are epiphytic in nature, but seen thriving in large populations on rocks as lithophytes also. Sikkim-Himalayas is home to four Pleiones, Pleione hookeriana, (Lindl.) Rollisson, Pleione humilis, (Sm) D.Don, Pleione maculata, (Lindl.) Lindl. & Paxton., and , (Sm.) D.Don.

Interestingly, Pleione hookeriana, (Lindl) B.S. Williams., holds the record for the highest growing epiphytic species of Sikkim-Himalayas, at an altitude of 11800 ft in North Sikkim.

Pleione hookeriana, (Lindl.) Rollisson

Epiphyte, with small oval shaped pseudo bulbs covered with a few lax sheaths. solitary, 3 to 5 cm long and 1 to 1.5 cm cm in width, proceeding from the base of the adult pseudo-bulb, narrowly elliptic, acute, tapering towards the petiole. Leafy during flowering. Peduncle longer than the , enclosed in tubular imbricate sheaths. solitary, 2 to 3 cm across, floral bract about as long as the stalked ovary, arising from the apex of the pseudo-bulb and protruding through the petiole of the leaf. Sepals spreading, sub-equal in length, elliptic to oblong, the dorsal slightly narrowed than the lateral, five nerved. Petals spreading, narrower and longer than the petals, obtuse, 5 to 7 nerved. Lip sub-reniform, cordate at base, broader in its posterior half, minutely erose in its anterior portion, apex retuse, disc with 7 ciliate ridges from the base to apex. Column long and curved, broadly winged. Pollinia obliquely elliptic.

Sepals and petals are of various shades of pale pink to rose, slightly darkening towards the margins. Lip almost white with a few reddish brown markings on its disc. The ciliate ridges are bright yellow.

Grows at altitudes between 5600 to 11800 ft and blooms in the months between May and July.

Population in Darjeeling: Singhalila National Park, Tiger Hills Population in Sikkim: Zema III, Lachen, Lachung in North Sikkim; Ravangla and Maenum Wildlife Sanctuary in South Sikkim. Status: Locally common.

Pleione humilis, (Sm) D.Don Epiphyte, with small narrowly ovoid tapering pseudo-bulbs, covered with many fibrous sheaths. Leaves solitary, membranous, 7 to 10 cm long and 3 to 4 cm in width, elliptic, acute, tapering to the sessile base. Leaves-less during flowering. Flowers solitary, 2 to 4 cm across, peduncle from the base of the pseudo-bulb, covered to the apex in tubular sheaths. Sepals spreading, sub-equal, oblong and acute, five nerved. Petals much narrower than the petals, obtuse, 3 to 5 nerved. Lip shortly clawed, sub-orbicular when spread, side lobes absent, concave in the lower part but expanding towards its mouth, apex slightly notched, with fimbriate margins. Column very long, with expanded apex, pollinia elliptic.

Sepals and petals are white. Lip white based with many reddish brown streaks and markings from base to apex.

Grows at altitudes between 6500 to 9000 ft and blooms in the month of February. Population in Darjeeling: Lava, Ghoom, Pashupati. Population in Sikkim: Barsey, Okhrey in West Sikkim Status: Locally common

Pleione maculata, (Lindl.) Lindl. & Paxton.

Epiphyte, pseudo-bulbs varying in shape at different stages of growth, generally cylindric to barrel shaped, its surface mottled with purplish brown, enveloped by loose brown fibers. Leaf in pairs, 6 to 15 cm long and 3 to 4 cm in width, narrowly elliptic-oblong, acute, narrowed to the petiole, base sheathed with bracts having nodular inflations. Leaf-less during flowering. Flowers solitary, erect, large, 5 to 6 cm across, rising from the base of the pseudo-bulb by a very short peduncle covered in a large spathaceous bract with broad emarginate apex, longer than the ovary. Sepals spreading, sub-equal, oblong to lanceolate, sub-acute, 7 nerved. Petals spreading, narrower than the sepals, of the same length or slightly shorter than latter, oblong, five to seven nerved. Lip broadly elliptic, three lobed, the basal part convolate round the column; the lateral lobes entire and narrower; the terminal broader, with sub-entire edges and broad apex. The disc with 5 to 7 fimbriate ridges. Column long and slightly curved, its apex winged. Pollinia elliptic.

Sepals and petals pure white, occasionally with streaks of dark brownish pink. The lip is white based with its interior marked with yellow and brownish pink streaks. The fimbriate ridges are yellow.

Grows at altitudes between 450 to 1200 ft and blooms in the month of October.

Population in Darjeeling: Surek, Samthare, Pangabhari. Population in Sikkim: Dzongu in North Sikkim Status: Rare and highly threatened.

Pleione praecox, (Sm.) D.Don.

Mostly epiphytic, seen also growing on rocks and even as terrestrial. Pseudo-bulbs vary in shape from cylindric to barrel, surface mottled with brown and imperfectly sheathed with fibers. Leaves in pairs, 6 to 14 cm long and 2 to 4 cm in width, membranous, elliptic to oblong, many-nerved, narrowed at the base to the petiole. Leaf less during flowering. Peduncle from the base of the pseudo bulb. Flowers solitary, mostly pendulous, large, 4 to 6 cm across. Floral bract obovoid, obtuse, as long as the stalked ovary. Sepals spreading, sub-equal and lanceolate. Petals spreading, much narrower than the sepals. Lip ovate to orbicular, side lobes absent, the basal convolate round the column, the anterior concave, the mouth wide open with irregular lobulate edges, the apex slightly bifid. The disc with three laciniate lamellae. Column very long, with a short sac at the base. Pollinia clavate.

Sepals, petals and lip are of various shades of rose to pink, sometimes darker or lighter. The disc of the lip got many dull yellow to brown spots, the lamellae is of a bright yellow shade. However, several colour forms of this species are spotted on various locations like pure white form, with only the lip with white etc. Grows at altitudes between 4800 to 7500 ft and blooms in the month of September, October and November.

Population in Darjeeling: Lava, Darjeeling, Ghoom, Shinghalaila National Park Population in Sikkim: Maenum Wildlife Sanctuary, Tendong in West Sikkim. Barsey in West Sikkim. Status: Common.

Interesting find All the Pleiones produce only solitary flowers. However, a recent find has brought out the evidence of Pleione hookeriana, (Lindl) B.S. Williams., producing a twin flower. The find has puzzled the botanical world, as the twin flower formation in Pleiones are very rare.

References: 1) “The Flora of British ” by Sir. J.D. Hooker. 2) “The Orchids of the Sikkim-Himalayas” by Sir. George King and Robert Pantling.