Oeoniella polystachys (Thouars) Schltr., Beih. Bot. Centralbl. 36(2): 177 (1918).
Angraecum polystachyum (Thouars) A.Rich., Mém. Mus. Hist. Nat. 4: 66 (1818).
Epidendrum polystachys Thouars, Hist. Orchid.: t. 82 (1822).
Aeranthes polystachya (Thouars) Rchb.f. in W.G.Walpers, Ann. Bot. Syst. 6: 901 (1864).
Listrostachys polystachys (Thouars) Rchb.f. in W.G.Walpers, Ann. Bot. Syst. 6: 909 (1864).
Beclardia polystachya (Thouars) Frapp., Orch. Reun. Cat. Esp. Ind.: 12 (1880).
Oeonia polystachya (Thouars) Benth. & Hook.f., Gen. Pl. 3: 584 (1883).
Angorchis polystachya (Thouars) Kuntze, Revis. Gen. Pl. 2: 651 (1891).
Epidorkis polystachya (Thouars) Kuntze, Revis. Gen. Pl. 2: 659 (1891).
Monixus polystachys (Thouars) Finet, Mém. Soc. Bot. France 9: 18 (1907).
Macradenia polystachya Spreng., Syst. Veg. 3: 726 (1826).
Angraecum pescatorianum Lindl., J. Hort. Soc. London 4: 263 (1849).
Listrostachys pescatoriana (Lindl.) S.Moore in J.G.Baker, Fl. Mauritius: 254 (1877).
Angraecum kimballianum auct., Bull. Misc. Inform. Kew 2(App.): 38 (1890).
An erect, somewhat vinelike, 24 in. (60 cm) epiphyte. Pseudobulb/stems: 3-24 in. (7-60 cm) long by about 0.2 in. (0.5-0.6 cm) wide. Stems are usually shorter than 24 in. (60 cm). The rigidly erect stems produce numerous branches. The older parts of the stems are semiwoody and produce roots along most of the stem to within 2-4 in. (5-10 cm) of the apex. Roots are 0.1 in. (0.2-0.3 cm) in diameter. Stems are densely leafy along their length and covered by tight-fitting, overlapping leaf sheaths. Hillerman and Holst (1986) reported, "Plants of Oeoniella polystachys are 10-30 cm tall and can be prevented from growing pendent and straggly by judicious pruning." Leaves: 1-2 in. (2.5-5.0 cm) long by 0.5 in. (1.2 cm) wide. Cultivated plants may have leaves that are 2-4 in. (5-11 cm) long by 0.6-0.8 in. (1.5-2.0 cm) wide. The spreading, closely spaced, fleshy, oblong leaves are alternately arranged in two rows along the stem. Inflorescence: 6-10 in. (15-25 cm) long. Flower spikes are usually erect to arching but may be horizontal to suberect. Inflorescences emerge along the stem at the axils of leaf sheaths. On well-grown plants, a single stem may produce 5-7 inflorescences at the same time. Each flower is carried on a pedicellate ovary that is about 0.3 in. (0.8 cm) long. Flowers: 12-15. The lacy, very dainty blossoms may be white to off-white, becoming greenish toward the base of the sepals and petals. They are fragrant during the early evening and last for 3-4 weeks, sometimes even longer. Flowers, which are 0.8-1.6 in. (2-4 cm) across, are usually held with the lip uppermost. The narrowly linear-lanceolate sepals are 0.5-0.6 in. (1.2-1.6 cm) long with sharply pointed tips. The narrowly linear petals, which are also sharply pointed, may be a little shorter than the sepals. The 3-lobed, trumpet-shaped lip is about 0.6 in. (1.6 cm) long. The broad lateral lobes have scalloped margins and curve to form a tube around the column. The midlobe is narrowly linear to threadlike with a long-tapering, sharply pointed tip. The spur at the base of the lip tapers toward the tip and is about 0.2 in. (0.6 cm) long. The very short column is wider than it is long.
This orchid grows on trees in the hot lowlands of eastern Madagascar and in the Sambirano Valley in the northwestern Madagascar. HIllerman and Holst (1986) reported, "In nature the species is very strong-growing, and its stems and root system surround the tree trunk and branches on which it perches. The plant is usually found on trees whose branches admit filtered sunlight, often on isolated trees in close proximity to the seashore, where there is high humidity and considerable warmth."
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W. Indian Ocean
Bechtel, H., P. Cribb, and E. Launert. 1980. Manual of cultivated orchid species. MIT Press, Cambridge, Mass. De la Bathie, H., and H. Humbert. [1939, 1941] 1981. Flora of Madagascar. vols. I-II. The Government of Madagascar and the National Museum of Natural History, Paris. Translated and published in 1 vol., Steven D. Beckman, 621 Palm Ave., Lodi, CA, U.S.A. 95240. Hamilton, R. 1988. When does it flower? 2nd ed. Robert M. Hamilton, 9211 Beckwith Road, Richmond, B.C., Canada V6X 1V7. Hillerman, F. and A. Holst. 1986. An introduction to the cultivated Angraecoid orchids of Madagascar. Timber Press, Portland, Ore. WCSP (2017). 'World Checklist of Selected Plant Families. 10.03-2017; http://apps.kew.org/wcsp/
Bechtel, H., P. Cribb, and E. Launert. 1980. Manual of cultivated orchid species. MIT Press, Cambridge, Mass. (Photo) De la Bathie, H., and H. Humbert. [1939, 1941] 1981. Flora of Madagascar. vols. I-II. The Government of Madagascar and the National Museum of Natural History, Paris. Translated and published in 1 vol., Steven D. Beckman, 621 Palm Ave., Lodi, CA, U.S.A. 95240. (Drawing) Hillerman, F. and A. Holst. 1986. An introduction to the cultivated Angraecoid orchids of Madagascar. Timber Press, Portland, Ore. (Photo)
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