ORCHIDACEAE
Luisia Gaudich. Voy. Uranie, Bot. 426 (1829).
By: Lokesh R. Shakya
Taxon Description
Plants epiphytic, monopodial. Stems stout, erect, unbranched, rarely branched at base, terete, covered by tubular, persistent leaf sheaths. Leaves few to many, distichous, distant, linear, terete, fleshy, straight or weakly curved, acute. Inflorescence leaf-opposed, fewer than 6-flowered, racemose. Flowers usually small, fleshy, resupinate. Sepals similar, free, spreading. Petals free, slightly longer and narrower than the sepals, spreading upward or laterally. Lip fleshy, 3-lobed, distinctly divided into hypochile and epichile; hypochile concave or saccate, epichile directed forward, more or less cordate, variously coloured. Column subcylindrical, stout, foot absent, rostellum short, wide, pollinia 2, waxy, globose, attached by a short stipe to a single, broad viscidium.
Taxon Statistics
Worldwide about 50 species, distributed in tropical and subtropical Asia to W Pacific. Three species in Nepal.
Key to Species
1a Stem ca. 7 mm thick. Flowers 10–15 mm across. Lip ca. 7 mm …………… 2. L. trichorriza
b Stem ca. 2.5–4 mm thick. Flowers 5–8 mm across. Lip ca. 3.5–5 mm …………………….. 2
2a Petals spreading upwards. Lip ca. 3.5 mm, hypochile saccate ……………… 1. L. inconspicua
b Petals spreading laterally. Lip ca. 5 mm, hypochile concave ………………… 3. L. zeylianica
1. Luisia inconspicua (Hook.f.) King & Pantl., Ann. Roy. Bot. Gard. (Calcutta) 8: 203 (1898).
Cymbidium inconspiccum Wall. ex Hook.f., Ann. Roy. Bot. Gard. (Calcutta) 5(1): 46 (1895).
Gastrochilus inconspicuus (Hook.f.) Kuntze., Revis. Gen. Pl. 2: 661 (1891).
Plants 10–20 cm. Stem stout, ca. 4 mm wide, unbranched. Leaves 4–7, 3–8 X 0.2 cm. Inflorescence 4–5-flowered, short, rachis thick. Fertile bracts triangular, ca. 1 mm, acuminate, persistent. Flowers sepals and petals greenish-white, lip pale greenish-white with purple dots, 5 mm across. Pedicel and ovary ca. 4 mm. Dorsal sepal broadly oblong, 2.5 X 1.6 mm, obtuse, 1-veined. Lateral sepals broadly oblong, 3 X 1.6 mm, spreading, oblique, obtuse, 1-veined. Petals oblong, 3 X 1.3 mm, spreading upward, obtuse, 1-veined. Lip ca. 3.5 mm, 3-lobed, fleshy, hypochile saccate with erect rounded lateral lobes; epichile cordate, recurved. Column ca. 2 mm.
Distribution: Nepal, W Himalaya, E. Himalaya, Assam-Burma, SE Asia.
Altitudinal range: 1,200 m.
Ecology: Epiphytic in forest.
Flowering: April–May.
2. Luisia trichorrhiza (Hook.) Blume, Rumphia 4: 50 (1849).
Vanda trichorrhiza Hook., Exot. Fl. 1: t. 72. (1823).
Plants 10–25 cm. Stem stout, ca. 7 mm wide, unbranched (rarely branched). Leaves 4–6, 10–15 X 0.2–0.4 cm. Inflorescence 4–5-flowered, short, rachis thick. Fertile bracts ovate-triangular, ca. 2 mm, acute, persistent. Flowers sepals and petals pale green, lip dark purple1–1.5 cm across. Pedicel and ovary ca. 5 mm. Dorsal sepal oblong, 5–8 X 1–1.5 mm, obtuse, 3-veined. Lateral sepals ovate, 6–8 X 1.5–2 mm, spreading, obtuse, 3-veined. Petals oblong, 7–10 X 1.3 mm, spreading upward, obtuse, 3-veined. Lip ca. 7 mm, 3-lobed, fleshy, hypochile concave with erect rounded lateral lobes; epichile broadly cordate, ridged, tapering-subtruncate. Column ca. 2 mm.
Distribution: Nepal, W Himalaya, E. Himalaya, Assam-Burma, SE Asia.
Altitudinal range: 1,000–1,300 m.
Ecology: Epiphytic in subtropical forest.
Flowering: March — April.
3. Luisia zeylianica Lindl., Fol. Orchid. 4: 3 (1853).
Plants 8–22 cm. Stem stout, ca. 2.5 mm wide, unbranched or branched. Leaves many, 5–8 X 0.1–0.2 cm. Inflorescence arising through the leaf sheath, 1–3-flowered, short, rachis thick. Fertile bracts ovate-triangular, ca. 2 mm, acute, persistent. Flowers sepals and petals pale green or pale yellow, lip dark maroon, 6–8 mm across. Pedicel and ovary ca. 6 mm. Dorsal sepal oblong-ovate, 3–4 X 2 mm, obtuse or subacute. Lateral sepals ovate-lanceolate, 3.5—4.5 X 2 mm, spreading, acute. Petals oblong, 4.5—5.5 X 1.5 mm, spreading, obtuse. Lip ca. 5 mm, 3-lobed, fleshy, hypochile concave with erect rounded lateral lobes; epichile triangular cordate with maroon bands . Column ca. 2.5 mm.
Distribution: Nepal, W Himalaya, E. Himalaya, Assam-Burma.
Altitudinal range: 1,000–1,300 m.
Ecology: Epiphytic on broadleaved trees in subtropical forest.
Flowering: May–June.