ORCHIDACEAE
Odontochilus Blume, Fl. Javae Nov. Ser. 1: 66 (1858).
By: Lokesh R. Shakya
Taxon Description
Plants terrestrial. Rhizome creeping, noded, fleshy, rooting from nodes, rarely coralloid. Stem leafy, ascending or erect, with loose tubular sheaths at base, rooting at nodes. Leaves green, cauline, ovate or ovate-lanceolate, distant or arising from stem apex, petiolate with the base dilated into a tubular amplexicaul sheath, rarely sessile. Inflorescence terminal, a laxly 1- to many-flowered raceme. Flowers resupinate, variously coloured, sepals and petals white or green, lip white or yellow. Sepals and petals free, lateral sepals spreading, rarely projecting forward, oblique, petals oblique, connivent with dorsal sepal to form a hood. Lip 3-lobed, spurless, adnate to the column base, spreading, hypochile saccate, mesochile channeled, entire, crenulate, fimbriate or toothed, epichile with a divergent 2-lobed blade. Column short, fleshy in front, winged or keeled,rostellum elongate, stigmas ventral, under the rostellum, pollinia 2, granular.
Taxon Statistics
Worldwide about 70 species, distributed in Himalaya and SW Pacific. Five species in Nepal.
Key to Species
1a Leaves sessile or subsessile, 4–7 mm. Rhizome coralloid. Petals lobed …….. 4. O. nandae
b Leaves petiolate, longer than 10 mm. Rhizome creeping. Petals unlobed ……………………. 2
2a Leaves dark green above, with white veins. Flowers yellow. Margin of lip mesochile pectinate ………………………………………………………………. 3. O. lanceolatus
b Leaves light or dark green above, without white veins. Flowers white or white with greenish sepals. Margin of lip mesochile entire ……………………………………………… 3
3a Leaves distant along stem. Lip hypochile saccate ……………………………… 5. O. pumilus
b Leaves arising from stem apex. Lip hypochile bisaccate …………………………. 4
4a Sepals white. Margin of lip mesochile shallowly crenulate, epichile lobes facing forward, apex obtuse ………………………………………………………………………. 1. O. crispus
B Sepals green with white margin. Margin of lip mesochile fimbriate, epichile lobes diverging, apex obliquely truncate ……………………………………………………2. O. elwesii
1. Odontochilus crispus (Lindl.) Hook. f., Fl. Brit. India 6: 99 (1890).
Anoectochilus crispus Lindl., J. Proc. Linn. Soc., Bot. 1: 180 (1857).
Plants 10–17 cm. Stem 4–6 cm, ascending, glabrous. Leaves 3-6, adaxially dark green, ovate, 1.5–2.5 X 1–1.5 cm, acute, laxly arising from stem apex, petiolate; petiole 1–1.5 cm, base expanded, sheathed. Inflorescence 5–7 cm, laxly 3-4-flowered; peduncle 2–4 cm, pubescent; rachis pubescent. Sterile bracts 1 or 2. Fertile bracts lanceolate, 7–15 X 3– mm, acuminate. Flowers white, ca. 15 mm. Pedicel and ovary ca. 9 mm, cylindrical, pubescent. Dorsal sepal narrowly ovate, cymbiform, ca. 5 X 4 mm, acuminate, outer surface pubescent. Lateral sepals spreading, narrowly elliptic, oblique, ca. 7 x 3 mm, subacute, outer surface pubescent. Petals triangular, falcate, ca. 6 X 2 mm, glabrous, acuminate. Lip Y-shaped, ca. 15 mm; hypochile slightly dilated, bisaccate, with longitudinal septum, fleshy with callus; mesochile ca. 6 mm, margin incurved and shallowly crenulate; epichile 2-lobed; lobes diverging, facing forward, oblong to obovate, ca. 7 × 4 mm, margin crenulate, apex obtuse. Column 2 mm.
Distribution: Nepal, E Himalaya, Assam-Burma, SE Asia.
Altitudinal range: 1900 m.
Ecology: Damp places in forests.
Flowering: August.
2. Odontochilus elwesii C.B. Clarke ex Hook.f, in Fl. Brit. India. 6: 100 (1890).
Plants ca. 10 cm. Stem 2 cm, ascending or erect, pubescent. Leaves 3, adaxially deep to dark green, ovate-lanceolate, 1.5-2 × 1-1.5 cm, acute, laxly arising from apex, petiolate; petiole 5–10 mm, base expanded, tubular, tubular sheath clasping stem. Inflorescence 7 cm, with single terminal flower; peduncle 6 cm, with sterile bracts, pubescent; rachis pubescent. Sterile bract 1. Fertile bracts ovate-lanceolate, ca. 7 mm. acuminate. Flowers sepals green with white margin, apex purplish white, petals and lip white, ca. 16 mm. Pedicel and ovary ca. 10 mm, cylindric-fusiform. Dorsal sepal ovate, cymbiform ca. 7 X 4 mm, acute. Lateral sepals spreading, ovate, oblique, ca. 9 X 5 mm, acute. Petals ovate, strongly oblique, ca. 7 X 4 mm, acute. Lip ca. 14 mm, 3-lobed; hypochile bisaccate with central longitudinal septum and fleshy subsquare callus on either side; mesochile ca. 5 mm, with a fimbriate flange along either margin; epichile 2-lobed, lobes diverging, apex obliquely truncate. Column 4 mm.
Distribution: Nepal, E Himalaya, Assam-Burma, SE Asia.
Altitudinal range: 1800-2300 m.
Ecology: Damp places in forests.
Flowering: September.
3. Odontochilus lanceolatus (Lindl.) Blume, Coll. Orchid.: 80, t.29. (1859).
Anoectochilus lanceolatus Lindl., Gen. Sp. Orchid. Pl.: 499 (1840).
Plants 10–25 cm. Stem 15–21 cm, decumbent at base, glabrous. Leaves 4-6, adaxially dark green with white veins, ovate-lanceolate, 2–6 X 1–2 cm, acute, distant along stem, petiolate; petiole 1–1.5 cm, base expanded, tubular. Inflorescence laxly many-flowered; peduncle short, pubescent; rachis pubescent. Sterile bracts 1 or 2. Fertile bracts ovate-lanceolate, 5–10 X 3 mm, acuminate. Flowers yellow, 15–20 mm. Pedicel and ovary 5–10 mm, fusiform, glabrous. Dorsal sepal ovate, ca. 7 X 4 mm, acute. Lateral sepals spreading, ovate-elliptic, oblique, ca. 4.5 x 2.2 mm, acute. Petals broadly ovate, strongly oblique ca. 4 x 2.5 mm, acuminate. Lip 15 mm, 3-lobed; hypochile saccate with longitudinal septum and 1 curved callus on either side; mesochile 4–6 mm, pectinate along both margin; epichile 2-lobed, lobes diverging, obliquely truncate. Column 2 mm.
Distribution: Nepal, E Himalaya, Assam-Burma, SE Asia.
Altitudinal range: 1600 – 1900 m.
Ecology: Damp open places.
Flowering: August-September.
4. Odontochilus nandae Raskoti & H. Kurzweil., Phytotaxa 233(3):293 (2015).
Plants 8–10 cm. Rhizome coralloid. Stem 4–5 cm, erect, glabrous, pinkish. Leaves 1 ocassionally 2-3, adaxially dark green, ovate, 4–7 X 4–5 mm, acute, subsessile; base sheating. Inflorescence 4–5 cm, 3 to 4 flowered, secund; peduncle cylindric, pubescent; rachis pubescent. Sterile bracts 1 or 2. Fertile bracts elliptic-ovate, 4–5 X 2.5–3 mm, acuminate. Flowers sepals olive pinkish, lip white, ca. 7 mm. Pedicel and ovary 7–10 mm, cylindric, pubescent. Dorsal Sepal ovate, cymbiform, ca. 4–5 X 2.5 mm, obtuse. Lateral sepals spreading, oblong, oblique, ca. 5 x 2 mm, obtuse, 1-veined, outer surface pubescent. Petals oblong, oblique, 4–5 X 1.5–2 mm, unequally bilobed, obtuse, 1-veined. Lip 7–9 mm, 3-lobed; hypochile saccate with two ligulate calli; mesochile 3–4 mm, irregularly erose margin; epichile 2-lobed, lobes diverging, obovate, entire. Column 4 mm.
Distribution: Endemic to Nepal.
Altitudinal range: 2400 m.
Ecology: On humus-rich litter in shade.
Flowering: August.
5. Odontochilus pumilus Hook. f., Fl. Brit. India 6: 99 (1890).
Myrmechis pumila (Hook. f.) Tang & F. T. Wang.
Plants 3–10 cm. Rhizome creeping. Stem 5–10 cm, decumbent at base, glabrous. Leaves 4-6, ovate, 5–12 X 4–6 mm, acute, adaxially green, distant along stem, petiolate; petiole ca. 3–5 mm, sheathing at base. Inflorescence ca. 3 cm, arising from apex of stem, 1–3-flowered, pubescent. Sterile bracts 1. Fertile bracts lanceolate, 4–6 mm, acute. Flowers white, 10–12 mm. Pedicel and ovary 6–8 mm, slightly pubescent. Dorsal sepal cymbiform, 5 X 2 mm, obtuse. Lateral sepals projected forward, suboblique 5 X 3 mm, subacute. Petals oblong or oblanceolate, oblique, 5 X 2 mm, obtuse. Lip 5–6 mm; hypochile dilated, saccate, sac with two lateral calli; mesochile ca. 2 mm, narrow, convolute, margin crenulate; epichile 2-lobed, lobes diverging, truncate. Column ca. 2 mm.
Distribution: Nepal, E Himalaya, Assam-Burma, SE Asia.
Altitudinal range: 2500 – 2700 m.
Ecology: Growing on mossy and shady ground.
Flowering: July.