ORCHIDACEAE
Dienia Lindl., Bot. Reg. 10: t. 825 (1824).
By: Bhakta B. Raskoti
Taxon Description
Terrestrial herbs. Roots emerged from base of pseudobulbs. Pseudobulbs ovoid or conic, often sheathed. Stems cylindric, often creeping. Leaves petiole sheathing at base. Inflorescence racemose; floral bracts persistent. Flowers not resupinate or resupinate, green, brown, yellow, pink, or purple. Dorsal sepal spreading, free; lateral sepals free or fused, spreading. Petals often narrower than sepals, free; lip entire or lobed, lacking auricles at base, apical margin entire or toothed, lacking a spur, callus absent, cushionlike or obscurely transversely ridged. Column lacking a foot; pollinia 4, clavate; stigma semicircular or transversely elliptic; rostellum obtuse at apex. Fruit ovoid to obovoid-ellipsoid.
Taxon Statistics
Worldwide 5 species, distributed in South Asia, South East Asia, East Asia, East Himalaya, West Himalaya and Australasia. Two species in Nepal.
Key to Species
1a Plant with 1 leaf. Floral bracts inclined. Lip entire…………………………..…………………..…………………………………………………..…………………..………………….1. D. cylindrostachya
b Plant with 3 or 4 leaves. Floral bracts refluxed. Lip 3-lobed at apex……………………..…………………..………………………………………………………………….……………… 2. D. ophrydis
1. Dienia cylindrostachya Lindl., Gen. Sp. Orchid. Pl.: 22(1830).
Malaxis cylindrostachya (Lindl.) Kuntze; Microstylis cylindrostachya (Lindl.) Rchb.f.
Plants 15–37 cm tall. Pseudobulbs conic, 1–2 X 0.5–1 cm, sheathed. Leaf 1; sheathlike petiole 3–7 cm; lamina elliptic to ovate, 5–12 X (1–)2–5 cm, apex obtuse. Inflorescence racemose, 9–20 cm; rachis 5–13 cm, many flowered. Floral bracts lanceolate, ca. 0.5–3 X 1 mm, inclined, apex acute. Flowers yellowish green, ca. 1.5–3 mm across. Pedicel and ovary 1–3 mm. Dorsal sepal ovate, 1.5–2.5 X 0.5 mm, apex acuminate. Lateral sepals similar to dorsal sepal. Petals linear-lanceolate, 1–2 X 0.5 mm, apex acute. Lip broadly ovate, 1–2 X 1–1.5 mm, entire, ridged at middle, margin denticulate, apex apiculate. Column ca. 0.5 mm. Fruit ovoid, 2–3 X 2–2.5 mm.
Distribution: Nepal, Assam-Burma, Tibetan Plateau, S Asia, E Himalaya, E Asia, SE Asia and W Himalaya.
Altitudinal range: 2000–3400 m.
Ecology: Terrestrial on cloudy forests.
Flowering: July–August. Fruiting: August–September.
2. Dienia ophrydis (J.Koenig) Seidenf., Contr. Orchid Fl. Thailand. 13: 18(1997).
Epidendrum ophrydis J.Koenig in Retzius, Observ. Bot. 6: 46 (1791); Crepidium ophrydis (J.Koenig) M.A.Clem. & D.L.Jones; Dienia congesta Lindl.; D. latifolia (Sm.) M.A.Clem. & D.L.Jones; Liparis krempfii Gagnep.; Malaxis latifolia Sm.; M. ophrydis (J.Koenig) Ormerod; Microstylis congesta (Lindl.) Rchb.f.
Plants 21–41 cm tall. Pseudobulbs cylindric, 1–5 X 1–1.5 cm, sheathed. Leaves 3 or 4; sheathlike petiole 2–6 cm; lamina obliquely ovate, ovate-elliptic or elliptic-lanceolate, (4–)10–19 × (1.5–2–)3–6 cm, apex acuminate. Inflorescence racemose, 20–27 cm; rachis 3–8 cm, many flowered. Floral bracts narrowly lanceolate, 2–5 X 1–1.5 mm, reflexed, apex acuminate. Flowers purplish red to greenish yellow, 2–4 mm across. Pedicel and ovary 2–4 mm. Dorsal sepal oblong, 2–3.5 X 1–2 mm, apex obtuse. Lateral sepals obliquely ovate, 2–3 X 1–1.5 mm, obtuse. Petals linear, 2–3.5 X 0.5–1 mm, apex obtuse. Lip broadly ovate, 2–3 X 2–2.5 mm, 3-lobed near apex; lateral lobes triangular, 0.5 X 0.5 mm, apex acute; mid-lobe narrowly ovate, 0.5–1 X 1 mm, apex obtuse. Column 1–1.5 mm. Fruit obovoid-ellipsoid, 4–6 X 3 mm.
Distribution: Nepal, Assam-Burma, S Asia, E Himalaya, E Asia, SE Asia, Australasia, and W Himalaya.
Altitudinal range: 900–1500 m.
Ecology: Terrestrial on thickets or open forests.
Flowering: June–August. Fruiting: August–November.