ORCHIDACEAE
Gastrochilus D. Don, Prodr. Fl. Nepal.: 32 (1825).
By: Lokesh R. Shakya
Taxon Description
Herbs, epiphytic, monopodial. Stems short or elongate, pendulous or arching, rarely erect, base covered with leaf sheaths. Leaves distichous, slightly fleshy, coriaceous, oblong to oblong-lanceolate, base sheathed, amplexicaule, apex acute or obtuse with unequally bilobed, rarely with awns or teeth. Inflorescence leaf-opposed, short, subumbellate or subcorymbose, few- to many-flowered. Flowers variously coloured with scattered spots or blotches, small to medium sized. Sepals and petals free, similar, spreading. Lip firmly attached to column base, hypochile globose, saccate, unlobed, rarely with narrow lateral lobes, epichile spreading forward, flat, shape various (orbicular, subtriangular, reniform), adaxially glabrous or with hairs, ecallose or callose, margin entire or variously incised. Column short, thick, footless, rostellum short, 2-lobed, pollinia waxy, 2, subglobose, grooved, connected to long narrow stipe wih bilobed visvidium at base.
Taxon Statistics
Worldwide about 50 species, distributed in tropical and subtropical Asia. Seven species in Nepal.
Key to Species
1a Leaves 1.5–3 X 0.3–0.5 cm ……………………………………………………………….. 2
b Leaves 6–28 X 1–4 cm ……………………………………………………………………. 4
2a Apex of leaf without awns or dentate. Lip epichile ecallose ……………… 7. G. pseudodistichus
b Apex of leaf with awns or dentate. Lip epichile callose ………………………………………… 3
3a Apex of leaf with awn. Lip hypochile sac straight, base unlobed, epichile margins entire ……………………………………………………………………………….. 5. G. distichus
b Apex of leaf minutely dentate. Lip hypochile sac slightly curved forward, base distinctly 2-lobed, epichile lateral margins erose …………………………………………………….. 2. G. affine
4a Apex of leaf acute to acuminate, with awn or teeth …………………………………………… 5
b Apex of leaf obtuse, without awn or teeth …………………………………………………….. 6
5a Apex of leaf with 1 awn. Lip hypochile with erect narrow lateral lobes, epichile with ovate central cushion ………………………………………………………………. 1. G. acutifolius
b Apex of leaf with 2 or 3 teeth. Lip hypochile unlobed, epichile with deltoid central cushion ………………………………………………………………………………. 4. G. dasypogon
6a Lip epichile adaxially glabrous, margin laciniate…………………………….. 6. G. obliquus
b Lip epichile adaxially with white hairs towards periphery, margin fimbriate ………………………………………………………………………………. 3. G. calceolaris
1. Gastrochilus acutifolius (Lindl.) Kuntze, Revis. Gen. Pl. 2: 661 (1891).
Saccolabium acutifolium Lindl., Gen. Sp. Orchid. Pl.: 223 (1833).
Plants 9–15 cm. Stems slender, pendant or arching. Leaves 5-8, oblong to oblong-lanceolate, 10–15 X 1-–2 cm, distichous, coriaceous, slightly oblique, base sheathed; sheath clasping stem, apex acute to acuminate, unequally 2-lobed; one lobe with straight or curved awn. Inflorescence subcorymbose, 3–4.5 cm across, shorter than leaves; 6-10-flowered; peduncle ca. 3 cm, with 2 tubular sheaths; sheaths at distant. Fertile bracts broadly oblong, ca. 4 mm. Flowers sepals and petals with green outer surface and pale green with dull brown spots inner surface, lip white with a yellow center, speckled with purple on upper surface of epichile, ca. 2 cm across; pedicel and ovary slender ca. 1.5 cm. Sepals and petals subsimilar, spreading, oblanceolate, incurved, obtuse. Lip ca. 10 mm, hypochile saccate, sac ca. 4 mm across, ca. 3.5 mm tall, with erect narrow lateral lobes; epichile reniform, with distinct ovate glabrous cushion at center, on both side of central cushion covered with tubular hairs, margin fimbriate with glandular hairs. Column ca. 3 mm.
Distribution: Nepal, W Himalaya, E Himalaya, Assam-Burma.
Altitudinal range: 1,600 m.
Ecology: Epiphytic on Myrsine sp.
Flowering: November
2. Gastrochilus affinis (King & Pantl.) Schltr., Repert. Spec. Nov. Regni Veg. 12: 314 (1913).
Saccolabium affine King & Pantl., Ann. Roy.Bot. Gard. (Calcutta) 8: 228, t.304 (1808).
Plants ca. 6 cm. Stem pendulous, slender, unbranched, rarely branched, covered by leaf sheaths; sheaths overlapping. Leaves many, oblong-lanceolate to subspathulate, slightly falcate, 1.5–2.5 X 0.3–0.4 cm, distichous, fleshy, apex acute, minutely 2 or 3-dentate. Inflorescence corymbose or subumbellate, ca. 2.5 cm, 2-4-flowered; peduncle ca. 1 cm, slender, sheathed; sheaths distant. Fertile bracts triangular to ovate, ca. 1.5 mm, subacute. Flowers sepals, petals and lip pale green densely flushed with purplish brown, lip sac with scattered purplish spots, ca. 5.5 mm across. Pedicel and ovary ca. 6.5 mm. Sepals subsimilar, spreading, ovate-elliptic, ca. 4 X 1.5 mm, obtuse. Petals ovate-elliptic, ca. 4 X 1.5 mm, obtuse. Lip ca. 6 mm, hypochile saccate; sac 3 mm across, ca. 3.5 mm tall, slightly curved forward, narrowing down, distinctly 2-lobed; unlobed; epichile triangular, slightly decurved, lateral margins erose, disc adaxially glabrous, with 2 thick median ridges from base to apex. Column ca. 3 mm.
Distribution: Nepal, E Himalaya, Assam-Burma.
Altitudinal range: 2450 m.
Ecology:
Flowering: April.
3. Gastrochilus calceolaris (Buch.-Ham. ex Sm.) D. Don, Prodr. Fl. Nepal.: 32 (1825).
Aerides calceolaris Buch.-Ham ex Sm. in Rees, Cyclop. 39: Aerides no. 11 (1819).
Plants 10–20 cm. Stem short and pendulous, covered by leaf sheaths. Leaves narrowly oblong, 10–28 X 1–2.3 cm, distichous, falcate, apex obtuse, unequally 2-lobed. Inflorescence corymbose or subcorymbose, ca. 3.5 cm across, few to many flowered; peduncle glabrous, sheathed. Fertile bracts ovate, ca. 3 mm, acute. Flowers sepals and petals yellow to greenish, speckled with brown, blotched with red-brown, lip yellowish, speckled with red, 1–1.6 cm across. Pedicel and ovary 1-1.4 cm. Sepals similar, spreading, obovate-oblong, 8–10 X 3.5–5 mm, obtuse-rounded. Petals similar to sepals. Lip ca. 10 mm, hypochile saccate; sac 5 mm across, ca. 4 mm tall; unlobed; epichile suborbicular-triangular, margin fimbriate, disc adaxially with white hairs towards periphery, central yellowish purple-spotted cushion. Column ca. 3 mm.
Distribution: Nepal, W Himalaya, E Himalaya, Assam-Burma, SE Asia.
Altitudinal range: 1,000—2,000 m.
Ecology: Epiphytic on Daphniphyllum.
Flowering: February to April.
4. Gastrochilus dasypogon (Sm.) Kuntze, Revis. Gen. Pl. 2:661 (1891).
Aerides dasypogon Sm. in Rees, Cycl. 39(1): no. (1818).
Plants 6–9 cm. Stem erect. Leaves oblong to oblong-lanceolate, 6–10 X 2-–2.8 cm, distichous, coriaceous, with prominent mid-vein, slightly oblique, apex slightly bent upward, acute to acuminate, with two to three crowded, sharp, teeth. Inflorescence subumbellate, ca. 7 cm across, shorter than leaves; densely many-flowered; peduncle ca. 3 cm. Fertile bracts ca. 5 mm. Flowers sepals and petals with green outer surface and red inner surface, lip white with reddish-purple dots on upper surface of epichile, ca. 2 cm across.Pedicel and ovary slender ca. 10 mm. Sepals and petals subsimilar, spreading, oblanceolate, incurved, obtuse. Lip ca. 10 mm, hypochile saccate, unlobed; epichile reniform, with distinct deltoid glabrous cushion at center, on both side of central cushion fringed and thickly covered with short fibrous processes, margin fimbriate. Column ca. 3 mm.
Distribution: Nepal, E Himalaya.
Altitudinal range:
Ecology:.
Flowering:
Above description based on type (Hamilton’s coloured illustration from Nepal) housed at The Linnean Society, London (LINN).
5. Gastrochilus distichus (Lindl.) Kuntze, Revis. Gen. Pl. 2: 661 (1891).
Saccolabium distichum Lindl., J. Proc. Linn. Soc. Bot. 3: 36. (1858).
Plants 10–16 cm. Stem pendulous, slender, branched, covered by leaf sheaths. Leaves many, oblong-elliptic or oblong-lanceolate, slightly falcate, 1.5–2.5 X 0.4–0.5 cm, distichous, fleshy, apex acute with awns. Inflorescence subumbellate, ca. 4 cm, 2-4-flowered; peduncle ca. 2 cm, slender, lower part sheathed. Fertile bracts ovate-lanceolate, ca. 1.5 mm, acute. Flowers pale greenish or yellow, with brownish spots, ca. 5 mm across. Pedicel and ovary ca. 8 mm. Sepals similar, spreading, oblong-elliptic, 4—5 X 2—3 mm, obtuse. Petals oblong, ca. 4 X 3 mm, obtuse. Lip ca. 6 mm, hypochile saccate; sac 3 mm across, ca. 4 mm tall, straight, uniformly broad; unlobed; epichile suborbicular, margin entire, disc adaxially glabrous, with central cushion, base with 2-calli. Column ca. 3 mm.
Distribution: Nepal, W Himalaya, E Himalaya, Assam-Burma, SE Asia.
Altitudinal range: 2000–2400 m.
Ecology: Epiphytic on Quercus.
Flowering: March to May.
6. Gastrochilus obliquus (Lindl.) Kuntze, Revis. Gen. Pl. 2: 661 (1891).
Saccolabium obliquum Lindl., Gen. Sp. Orchid. Pl.: 223 (1833).
Plants 10—18 cm. Stem pendent, covered with overlapping leaf sheaths. Leaves 4—6, oblong, 6–16 X 2.5–4 cm, distichous, slightly falcate, apex obtuse, unequally 2-lobed. Inflorescence corymbose, 3–5 cm across, many flowered (rarely few flowered), opposite to leaves; peduncle glabrous, sheathed. Fertile bracts lanceolate, ca. 3 mm, acute. Flowers sepals and petals bright greenish-yellow, with brownish-purple spots, lip white with brownish, purplish spots speckled with red, 1–1.5 cm across. Pedicel and ovary 1–1.4 cm. Sepals similar, spreading, oblong-oblanceolate to spathulate, ca. 8 X 2.5 mm. Petals spreading oblong, ca. 5 X 2 mm. Lip ca. 8 mm, hypochile saccate; sac ca. 3.5 mm across, ca. 3.5 mm tall; unlobed; epichile subtriangular, adaxially glabrous with a central cushion, margin laciniate. Column ca. 2.5 mm.
Distribution: Nepal, E Himalaya, Assam-Burma, SE Asia.
Altitudinal range: 300 m.
Ecology: Epiphytic on Dillenia indica.
Flowering: October.
7. Gastrochilus pseudodistichus (King & Pantling) Schltr., Feddes Repert. Spec. Nov. Regni Veg. 12: 315 (1913).
Saccolabium pseudodistichum King & Pantling J. Asiat. Soc. Bengal 64(3): 341 (1896).
Plants 10–20 cm. Stem pendulous, slender, branched or unbranched, covered by tubular leaf sheaths. Leaves many, narrowly lanceolate, slightly falcate, 1.5-3 x 0.4-0.5 cm, distichous, fleshy, apex acuminate. Inflorescence subumbellate, ca. 3 cm, 4 to 6 flowered; peduncle 1–1.5 cm, sheathed; sheaths basal. Fertile bracts lanceolate, 1–2 X 0.4—0.6 mm. Flowers sepals and petals greenish with brown-purple spots; lip yellowish green; hypochile and column with brown-purple spots, epichile green, 8–10 mm across. Pedicel and ovary 3– 4.5 mm. Sepals similar, spreading, oblong-ovate, 4 x 2.5 mm, obtuse. Petals oblong, 4 x 2.5mm, obtuse. Lip ca. 4.5 mm, hypochile saccate; sac ca. 3 mm across, ca. 2 mm tall, straight, uniformly broad; unlobed; epichile broadly cordate, obtuse, entire, fleshy, disc adaxially glabrous, ecallose. Column ca. 2 mm.
Distribution: Nepal, E Himalaya, Assam-Burma, SE Asia.
Altitudinal range: 1900–2000 m.
Ecology: Epiphytic on Quercus.
Flowering: July.