ORCHIDACEAE
Oreorchis Lindl., J. Proc. Linn. Soc., Bot. 3: 26 (1858).
Diplolabellum F.Maek.
By: Bhakta Bahadur Raskoti
Taxon Description
Terrestrial herbs. Rhizome often producing a chain of pseudobulbs, roots fibrous. Pseudobulb subterranean, noded. Leaves 1–3, arising from apex of pseudobulb, linear, elliptic-lanceolate to oblong-lanceolate, plicate, tapering into a long petiole-like stalk at base, with sheaths at base. Inflorescence arising from node of pseudobulb, erect, with several tubular sheaths, racemose; rachis laxly to subdensely flowered; floral bracts persistent. Flowers half or fully opening, resupinate. Sepals and petals similar, free, spreading. Petals similar to dorsal sepal. Lip 3-lobed or entire, clawed at base, without a spur; disk usually with or without a pair of longitudinal lamellae or a callus. Column slightly arcuate, but without a conspicuous foot; anther terminal; pollinia 4, subglobose, attached to a globose viscidium, stigma oval. Fruit ellipsoid.
Taxon Statistics
Worldwide 19 species, distributed in East Himalaya, West Himalaya, Assam-Burma, East Asia, South Asia and Tibetan Plateau.
5 species in Nepal including one endemic.
Key to Species
1 a Plants with 2 or 3 leaves. Lateral lobes of lip linear……….………………………………………………………………………………………………………………..….3. O. micrantha
b Plants with a single leaf. Lateral lobes of lip oblong or falcately oblong……………………………………………………………………………………………………………..……..2
2 a Leaf lanceolate. Column more than 7 mm………………………………………………………………………………………………………………………………………………………………..3
b Leaf linear-lanceolate or elliptic-lanceolate. Column less than 7 mm………………………………………………………………………………………………………..……….……..4
3 a Rachis 2–4 cm, laxly 2–5-flowered. Flower 15–20 mm across………….……….……….……….……….……….……….……….……….…………..………..5. O. porphyranthes
b Rachis 7–10 cm, subdensely 6–14-flowered. Flower 10 mm across…………….……….……….……….……….……….……….……….……….……….………4. O. nepalensis
4 a Leaf linear-lanceolate. Lateral lobes of lip 1.5–2 mm, lip disk with longitudinal lamellae………………………………..………………………………………..1. O. foliosa
b Leaf elliptic-lanceolate. Lateral lobes of lip 1.5 mm, lip disk without longitudinal lamellae……………………………….………………….……………………2. O. indica
1. Oreorchis foliosa (Lindl.) Lindl. J. Proc. Linn. Soc., Bot. 3: 27 (1858).
Corallorhiza foliosa Lindl., Gen. Sp. Orchid. Pl.: 535 (1840).
Plants 20–34 cm tall. Roots fibrous. Pseudobulbs ovoid, 15–20 × 15–20 mm. Leaf 1, petiole-like stalk 2–3 cm; lamina linear-lanceolate, 12–14 × 1–1.4 cm, apex acute. Scape 20–34 cm, with 2 or 3 tubular sheaths below middle, sheaths 2.5–3 × 0.4–0.5 cm, apex obtuse. Rachis 4–10 cm, laxly 4–7-flowered. Floral bracts lanceolate, 2–4 × 1–1.5 mm, apex acuminate. Flowers dark yellow with purplish brown striations and spots, lip white with purplish red spots, 6–7 mm across. Pedicel and ovary 7–12 mm. Dorsal sepal linear-lanceolate, 7–9 × 1.5–2 mm, apex acute. Lateral sepals falcately oblong-lanceolate 7–8 × 1.5–2 mm, apex subacute. Petals falcately oblong-lanceolate, 7–9 × 2 mm, apex acuminate. Lip obovate-oblong or broadly oblong, 6–8 × 4–5 mm, 3-lobed; lateral lobes falcately oblong, ca. 1.5–2 mm, apex obtuse; mid-lobe subquadrate, ca. 3–4 × 4 mm, apex rounded; disk with longitudinal lamellae. Column arcuate, 6–7 mm. Fruit ellipsoid, ca. 10–15 × 5–6 mm.
Distribution: Nepal, E Himalaya, W Himalaya and Assam-Burma.
Altitudinal range: 2800–3000 m.
Ecology: Temperate woodlands and forests.
Flowering: July–August. Fruiting: September–October.
2. Oreorchis indica (Lindl.) Hook.f., Fl. Brit. India 5: 709 (1890).
Corallorhiza indica Lindl., J. Proc. Linn. Soc. Bot. 3: 26 (1858); Oreorchis foliosa var. indica (Lindl.) N.Pearce & P.J.Cribb
Plants 20–41 cm tall. Roots fibrous. Pseudobulbs ovoid or subellipsoid, 10 × 15 mm. Leaf 1, petiole-like stalk 1.5–2.5 cm; lamina elliptic-lanceolate, 10–14 × 1.5 cm, apex acute. Scape 18–39 cm, with 2 or 3 tubular sheaths below middle, sheaths tubular, 2–3 × 0.5 cm, apex obtuse. Rachis 3–7 cm, laxly 4–7-flowered. Floral bracts lanceolate, 3–4 × 1 mm, apex acuminate. Flowers dark yellow with many purplish brown striations and spots, lip white with purple red spots, 10–12 mm across. Pedicel and ovary 5–8 mm. Dorsal sepal oblong-elliptic, 8–10 × 1.5–2 mm, apex subacute. Lateral sepals falcately oblanceolate, 8–9 × 2 mm, apex acute. Petals falcately elliptic-lanceolate, 9–10 × 2 mm, apex acute. Lip broadly oblong, 6–8 × 4–5 mm, 3-lobed above middle or sometimes entire; lateral lobes oblong, ca. 1.5 × 1 mm, or absent, apex obtuse; mid-lobe suborbicular, ca. 5 × 5 mm, apex rounded and irregularly incised; disk without lamellae or calli. Column arcuate, 5 mm. Fruit not seen.
Distribution: Nepal, E Himalaya, W Himalaya, Assam-Burma, Tibetan Plateau and E Asia.
Altitudinal range: 2700–3800 m.
Ecology: Temperate woodlands and forests.
Flowering: July–August. Fruiting: September–October.
3. Oreorchis micrantha Lindl. J. Proc. Linn. Soc. 3: 27 (1858).
Oreorchis rolfei Duthie
Plants 17–37 cm tall. Roots fibrous. Pseudobulbs corm-like, 5–20 × 10–15 mm. Leaves 2 or 3, linear, 15–30 × 0.5–1 cm, apex acuminate, petiole like-stalk 2–3 cm. Scape 17–37 cm, with 1 or 2 tubular sheaths below middle, sheaths 3–4 × 0.4 cm, apex obtuse. Rachis 2–4 cm, subdensely upto 15-flowered. Floral bracts lanceolate, 4–7 × 0.5–1 mm, apex acute or acuminate. Flowers sepals and petals pale yellow spotted with purple, lip white with purple spots; 5–10 mm across. Pedicel and ovary 10–20 mm. Dorsal sepal oblong-elliptic, 5–6 × 1.5–2 mm, apex acute. Lateral sepals elliptic-lanceolate, 5–7 × 1.5–2 mm, apex acute. Petals oblong-elliptic, 4–6 × 1–1.5 mm, apex acute. Lip obovate-oblong, 4–6 × 2–2.5 mm, 3-lobed; lateral lobes linear, 1.5–2 × 1 mm, apex acuminate; mid-lobe suborbicular to elliptic, 2–3 × 2–2.5 mm; disk with callus. Column arcuate, 2–3 mm. Fruit ellipsoid, 15–20 × 5–7 mm.
Distribution: Nepal, E Himalaya, W Himalaya, Assam-Burma, East Asia and Tibetan Plateau.
Altitudinal range: 2300–3300 m.
Ecology: Temperate woodlands and forests.
Flowering: June–July. Fruiting: September–October.
4. Oreorchis nepalensis N.Pearce & P.J.Cribb, Edinburgh J. Bot. 54: 315 (1997).
Plants 29–32 cm tall. Roots fibrous. Pseudobulbs oblong-ovoid, 15–20 × 7–10 mm. Leaf 1, petiole-like stalk 5–10 cm; lamina lanceolate, 15–30 × 0.8–1.7 cm, apex acute. Scape 29–32 cm, with 1 or 2 tubular sheaths below middle, sheaths tubular 3–5 × 2–3 cm, apex obtuse. Rachis 7–10 cm, subdensely 6–14-flowered. Floral bracts lanceolate, 5–7 × 1–1.5 mm, apex acute. Flowers brownish green or yellowish green, lip pale pink to white with purple spots; 10 mm across. Pedicel and ovary 10–13 mm. Dorsal sepal linear-lanceolate, 12–15 × 3–3.5 mm, apex subacute. Lateral sepals falcately lanceolate, 10–11 × 3–3.5 mm, apex acute. Petals oblong-lanceolate, 12–13 × 3–3.5 mm, apex obtuse. Lip obovate, 11–12 × 5–6 mm, 3-lobed near middle; lateral lobes oblong, 4 × 1.2 mm, apex obtuse; mid-lobe ovate-elliptic, ca. 7 × 6 mm, apex rounded; disk with 2 crescent-shaped lamellae. Column arcuate, 7–8 mm. Fruit ellipsoid, ca. 10–20 × 5–8 mm.
Distribution: Nepal and Tibetan Plateau.
Altitudinal range: 2700–2800 m.
Ecology: Temperate grassland slopes.
Flowering: June. Fruiting: July–October.
5. Oreorchis porphyranthes Tuyama, J. Jap. Bot. 50: 69 (1975).
Plants 17–23 cm tall. Roots fibrous. Pseudobulbs ovoid to globose 8–12 × 5–12 mm. Leaf 1, petiole-like stalk 2–2.5 cm; lamina lanceolate, 10–12 × 0.6–1 cm, apex acute. Scape 16–21 cm, with 2 or 3 tubular sheaths below middle, sheaths 2.5–4 × 0.3 cm, apex obtuse. Rachis 2–4 cm, laxly 2–5-flowered. Floral bracts lanceolate, 4–6 × 1 mm, apex acute. Flowers sepals and petals deep purple, lip white with purple spots; 15–20 mm across. Pedicel and ovary 14–20 mm. Dorsal sepal oblong-linear, 15–20 × 4.5–5 mm, apex obtuse. Lateral sepals oblong, 15–18 × 5 mm, apex apex subacute. Petals oblong, 14–16 × 4.5–5 mm, apex obtuse. Lip ovate-oblong, 10–12 × 9–10 mm, 3-lobed; lateral lobes obliquely oblong, 3–4 × 2 mm, apex obtuse; mid-lobe broadly ovate, 6–7 × 6–7 mm, apex rounded; disk with two raised lamellae. Column arcuate, 10 mm. Fruit not seen.
Distribution: Endemic to Nepal.
Altitudinal range: 3000–3700 m.
Ecology: Under shade on grassland slopes.
Flowering: May–June. Fruiting: July–October.