Angraecum

Vandeae subtribe Angraecinae. Garay’s (1973) treatment, dividing the genus into 19 sections, has been widely accepted.

Monopodial epiphytes, lithophytes and terrestrials, rooting at the base or along the stems. Stems short to elongate and vining, solitary to freely branching. Leaves alternate, distichous, leathery, strap-shaped, terete or bilaterally compressed, often obliquely bilobed at the apex, usually leathery. Inflorescences axillary, one-flowered, racemes or panicles, the floral bracts often dark brown. Flowers usually star-shaped, resupinate or not resupinate, usually fragrant at night, often waxy and glossy, white, green, or green and white, rarely with brown suffusion. Sepals and petals free, spreading, subsimilar, subequal, most frequently lanceolate. Lip unlobed or rarely obscurely three-lobed, usually concave, with a short to very long nectar spur. Column very short, without wings or a foot; pollinia 2, globose, grooved on one side, attached to a common viscidium or to a pair of distinct viscidia.

From the Latinized form of the Malay angurek, a term for large monopodial orchids such as Aerides and Vanda.

A genus of about 200 species from Tropical Africa, Madagascar, and adjacent islands with one species in Sri Lanka.

1 Leaves bilaterally compressed, semiterete, or terete. 2 1' Leaves planar, flat or v-shaped in cross-section. 9 2(1) Leaves bilaterally compressed. 3 2' Leaves terete or semiterete. 5 3(2) Stems elongate; plants clump-forming; inflorescences with flowers subequal to or shorter than the leaves. A. distichum 3' Stems short, fan-shaped; plants solitary stems or with limited basal offshoots; inflorescences with flowers surpassing the leaves. 4 4(3') Leaves to 1.9 in. (5 cm) long. A. aloifolium 4' Leaves to 8.6 in. (22 cm) long. A. leonis 5(2') Flowers resupinate, lip lowermost. 6 5' Flowers not resupinate, lip uppermost. 7 6(5) Dorsal sepal to 0.7 in. (1.8 cm) long; leaves to 1.8 in. (4.5 cm) long. A. palmicolum 6' Dorsal sepal to 1.8 in. (4.5 cm) long; leaves to 4.7 in. (12 cm) long. A. peyrotii 7(5') Lip longer than wide, to 0.3 in. (0.9 cm) wide. A. teretifolium 7' Lip wider than long, more than 1 in. (2.5 cm) wide. 8 8(7') Inflorescences to 1.9 in. (5 cm) long; leaves to 2.7 in. (7 cm) long. A. pseudofilicornu 8' Inflorescences to 3.9 in. (10 cm) long; leaves to 3.9 in. (10 cm) long. A. scottianum 9(1') Spurs short, as long as or less than 2.1 in. (5.5 cm) long. 10 9' Spurs long, longer than 2.1 in. (5.5 cm). 21 10(9) Flowers ochre. A. ochraceum 10' Flowers white and green. 11 11(10') Flowers not resupinate, the lip uppermost. 12 11' Flowers resupinate, the lip lowermost. 16 12(11) Leaves to 0.8 in. (2 cm) long; spur to 0.1 in. (3.5 mm) long or longer. A. gabonense 12' Leaves to 2.3 in. (6 cm) or longer; spur to 0.8 in. (2 cm) long or longer. 13 13(12') Flowers 1--3 per inflorescence; leaves equal to or less than 2.7 in. (7 cm) long. 14 13' Flowers 3--5 per inflorescence; leaves to 5.1 in. (13 cm) long. A. dendrobiopsis 14(13) Flowers larger, dorsal sepal to 1.2 in. (3.1 cm) long. A. conchiferum 14' Flowers smaller, dorsal sepal to 0.5 in. (1.4 cm) long. 15 15(14') Spur horizontal; flowers white. A. erectum 15' Spur pendent; flowers green. A. moandense 16(11') Flowers larger, dorsal sepal to 2.3 in. (6 cm) long. A. eichlerianum 16' Flowers smaller, dorsal sepal to 0.9 in. (2.2 cm) long. 17 17(16') Spur very short, to 0.2 in. (0.4 cm) long. 18 17' Spur longer, to 0.9 in. (1.7 cm) or longer. 19 18(17) Inflorescences with 5--7 flowers. A. bracteosum 18' Inflorescences one-flowered. A. dasycarpum 19(17') Leaves to 7.8 in. (20 cm) long. A. calceolus 19' Leaves to 2.3 in. (6 cm) long. 20 20(19') Spur to 2.1 in. (5.5 cm) long. A. coutrixii 20' Spur to 1 in. (2.7 cm) long. A. cultriforme 21(9') Leaves longer, more than 7.8 in. (20 cm) long. 22 21' Leaves shorter, to 7.8 in. (20 cm) long. 27 22(21) Flowers not resupinate, lip uppermost. 23 22' Flowers resupinate, lip lowermost. 24 23(22) Spur to 6.6 in. (17 cm) long. A. eburneum 23' Spur to 15.6 in. (40 cm) long. A. longicalcar 24(22') Spurs short, to 4.9 in. (12.5 cm) long. 25 24' Spurs longer, more than 7.8 in. (20 cm) long. 26 25(24) Sepals and petals opaque white; lip to 1.8 in. (4.5 cm) wide. A. magdalenae 25' Sepals and petals pale green; lip to 1.2 in. (3.2 cm) wide. A. praestans 26(24') Dorsal sepal to 4.3 in. (11 cm) long. A. sesquipedale 26' Dorsal sepal to 2.3 in. (6 cm) long. A. sororium 27(21') Flowers not resupinate, lip uppermost. 28 27' Flowers resupinate, lip lowermost. 33 28(27) Leaves short, less than 1 in. (2.5 cm) long. A. arachnites 28' Leaves longer, more than 1 in. (2.5 cm) long. 29 29(28') Dorsal sepal shorter, to 1.4 in. (3.5 cm) long. 30 29' Dorsal sepal longer, to 3.9 in. (10 cm) long. A. germinyanum 30(29) Inflorescences one-flowered. A. mirabile 30' Inflorescences with 2--6 flowers. 31 31(30') Spur s-shaped, to 3 in. (7.8 cm) long. A. reygaertii 31' Spur straight to gently curved, to 3.9 in. (10 cm) long or longer. 32 32(31') Peduncle to 0.4 in. (1 cm) long; petals and lateral sepals not falcate, spreading. A. florulentum 32' Peduncle to 2.3 in. (6 cm) long; petals and lateral sepals falcate. A. penzigianum 33(27') Spur folded back on itself. 34 33' Spur straight or gently curved, never folded back on itself. 36 34(33) Leaves shorter, to 3.9 in. (10 cm) long; dorsal sepal equal to or less than 1.9 in. (5 cm) long. 35 34' Leaves longer, to 8.4 in. (21.5 cm) long; dorsal sepal to 3.3 in. (8.5 cm) long. A. infundibulum 35(34) Inflorescences with 1--3 flowers; spur to 5.1 in. (13 cm) long. A. compactum 35' Inflorescences one-flowered; spur to 2.5 in. (6.5 cm) long. A. spectabile 36(33') Sepals and petals pale copper colored. A. vigueri 36' Sepals and petals white or green. 37 37(36') Flowers green and white. 38 37' Flowers white. 40 38(37) Inflorescences one-flowered; leaves to 1.9 in. (5 cm) long. A. bicallosum 38' Inflorescences not one-flowered, usually with 5--8 flowers; leaves more than 3.1 in. (8 cm) long. 39 39(38') Lip abruptly narrowed at the middle with a very narrow long-acuminate apex. A. humbertii 39' Lip gradually tapered to the apex, not acuminate. A. mahavavense 40(37') Ovary three-winged. A. borbonicum 40' Ovary not winged. 41 41(40') Pedicel and ovary longer, longer than 1.5 in (3.8 cm); inflorescences with 1--3 flowers. 42 41' Pedicel and ovary shorter, to 1.2 in. (3 cm) long; inflorescences one-flowered. 43 42(41) Plants small, leaves to 2.3 in. (6 cm) long; pedicel and ovary to 1.9 in. (5 cm) long. A. equitans 42' Plants larger, leaves to 7.8 in. (20 cm) long; pedicel and ovary to 3.1 in. (8 cm) long. A. protensum 43(41') Pedicel and ovary to 0.5 in. (1.3 cm) long; lip to 0.5 in. (1.4 cm) wide. A. obesum 43' Pedicel and ovary longer, to 1.2 in. (3 cm) long; lip wider, to 0.7 in. (1.8 cm) wide or wider. 44 44(43') Flowers smaller; lip to 0.7 in. (1.8 cm) long; petals to 0.2 in. (0.4 cm) wide. A. rutenbergianum 44' Flowers larger; lip to 1.2 in. (3.2 cm) long or longer; petals to 0.3 in. (0.9 cm) wide or wider. 45 45(44') Plants smaller; leaves to 2.7 in. (7 cm) long; dorsal sepal to 1.2 in. (3 cm) long. A. didieri 45' Plants larger; leaves to 4.7 in. (12 cm) long; dorsal sepal to 1.8 in. (4.7 cm) long. A. elephantinum

Braem, G. J. 1991. Angraecum popowii Braem, spec. nov. Schlechteriana 4/91:163-166; Nilsson, L. A., L. Jonsson, L. Rason and E. Randrianjohany 1985. Monophily and pollination mechanisms in Angraecum arachnites Schltr. (Orchidaceae) in a guild of long-tongued hawk-moths (Sphingidae) in Madagascar. Biol. J. Linn. Soc. 26:1-19; Bosser, J. 1987. Contribution à l’étude des Orchidaceae de Madagascar et des Mascareignes, XXII. Adansonia 9(3):249-254; Bosser, J. 1988. Contribution à l’étude des Orchidaceae de Madagascar et des Mascareignes, XXIII. Adansonia 10(1):19-24; Bosser, J. 1989. Contribution à l’étude des Orchidaceae de Madagascar et des Mascareignes, XXIV. Adansonia 11(1):29-39; Bosser, J. 1989(1990). Contribution à l’étude des Orchidaceae de Madagascar et des Mascareignes, XXVI. Adansonia 11:369-382; Bosser, J. and P. Morat 1972. Contribution à l’étude des Orchidacees de Madagascar, XVIII. Adansonia 12(1):73-78; van Ede, G. 1984. Angraecum stella-africa. S. Afr. Orchid J. 15(4):134-135; Garay, L. A. 1973. Systematics of the genus Angraecum (Orchidaceae). Kew Bull. 28:495-516; Hermans, J. and P. Cribb 1997. A new species of Angraecum (Orchidaceae) from Madagascar. Orchid Rev. 105(1214):108-111; Hermans, J. and I. la Croix 2001. Angraecum clareae Hermans, la Croix & P. J. Cribb sp. nov. Orchid Rev. 109(1237):43-46; Manning, J. and G. Wright 1982. An Angraecum new to Natal. S. Afr. Orchid J. 13(4):88-89; Morgans, J. F. C. 1976. Is Angraecum eburneum a facultative apomict? S. Afr. Orchid J. 7(3):92-93; Senghas, K. 1997. Vielfalt tropischer und suptropischer Orchideenstandorte und ihre Übertragung in die Kultur, dargestellt am Beispiel der Gattung Angraecum in Madagaskar mit einer neuen Art, Angraecum dollii. Journ. Orchideenfreund 4(1):13-25; Senghas, K. 1997. Vielfalt tropischer und suptropischer Orchideenstandorte und ihre Übertragung in die Kultur, dargestellt am Beispiel der Gattung Angraecum in Madagaskar mit einer neuen Art, Angraecum dollii, Teil II. Journ. Orchideenfreund 4(2):103-106; Stewart, J. 1979. Angraecum sesquipedale var. angustifolium. Fl. Pl. Africa 46:pl. 1836; Toilliez-Genoud, J. and J. Bosser. 1961. Contributions à l’étude des Orchidaceae de Madagascar IV, sur un Angraecum et un Cynorchis nouveaux. Adansonia 1:100-103; Williamson, G. 199##. A new species of Angraecum (Orchidaceae) from South Central Africa. Kew Bull. 51(2):557-559.