Aerangis

Vandeae subtribe Aerangidinae

Monopodial epiphytes. Stems short with thick greyish-white roots. Leaves alternate, distichous, leathery, usually obliquely bilobed at the apex. Inflorescences axillary arching-pendent racemes, often fractiflex, the floral bracts inconspicuous, often brown. Flowers starry, strongly two-ranked, white, usually fragrant in the evening. Sepals and petals free, spreading, subsimilar, subequal, often reflexed. Lip unlobed, subsimilar to the petals, strongly reflexed and often subparallel with the ovary, with an elongate nectar spur, the spur gently curved or spiralled, usually without callus. Column somewhat club-shaped, without wings or a foot; pollinia 2, sulcate, on a common linear stipe and variously shaped viscidium.

From the Greek aer, meaning air, and angos, meaning vessel, alluding to the elongate spurs common in the genus.

A genus of 60 species in Africa and Madagascar with one species extending to Sri Lanka.

1 Base of lip with a pair of small calli. A. cryptodon 1' Base of lip without any callus. 2 2(1') Leaves to 1.6 in. (4 cm) long; flowers 1--3 per inflorescence. 3 2' Leaves more than 1.9 in. (5 cm) long; flowers few to many. 4 3(2) Leaves green without any spotting; sepals and petals subsimilar, subequal. A. curnowiana 3' Leaves green with silvery spots; sepals and petals subsimilar but not equal, the sepals wider than the petals. A. punctata 4(2') Spur hooked at the apex. A. calantha 4' Spur variously shaped but without a hooked apex. 5 5(4') Petals twice as wide as the dorsal sepal; flowers pale yellow; the spur bent at the middle. A. citrata 5' Petals subequal to the dorsal sepal; flowers usually white; the spur curved or twisted, never bent. 6 6(5') Lip broadest above the middle. 7 6' Lip oblong or broadest below the middle. 12 7(6) Spur to 3.5 in. (9 cm) long or shorter. 8 7' Spur elongate, to 9 in. (23 cm) long. 11 8(7) Spur strongly incurved at the middle with the apex subparallel to the lip. A. luteo-alba 8' Spur gently curved at the middle, pendent. 9 9(8') Inflorescences shorter than the leaves, to 1.9 in. (5 cm) long. A. fastuosa 9' Inflorescences longer than the leaves, more than 7.8 in. (20 cm) long. 10 10(9') Spur to 1.6 in. (4 cm) long. A. alcicornis 10' Spur to 3.5 in. (9 cm) long. A. modesta 11(7') Spur gently curved at the base, without any spiral twisting. A. fuscata 11' Spur spirally twisted. A. kotschyana 12(6') Spur spirally twisted. 13 12' Spur straight or gently curved, never spirally twisted. 14 13(12) Spur to 9.7 in. (25 cm) long. A. splendida 13' Spur to 5.8 in. (15 cm) long. A. thomsoni 14(12') Spur short, to 1 in. (2.5 cm) long. 15 14' Spur longer, more than 1.9 in. (5 cm) long. 17 15(14) Inflorescences about three times as long as the leaves, to 9.7 in. (25 cm) long. A. pallidiflora 15' Inflorescences subequal to the leaves, to 5.8 in. (15 cm) long. 16 16(15') Spur to 0.5 in. (1.2 cm) long; inflorescences to 2.7 in. (7 cm) long; leaves without blackish spots. A. hyaloides 16' Spur to 1 in. (2.5 cm) long; inflorescnces to 5.8 in. (15 cm) long; leaves with blackish spots. A. ugandensis 17(14') Leaves with darker, reticulated venation. 18 17' Leaves without darker, reticulated venation. 20 18(17) Spur short, to 2.9 in. (7.5 cm) long. A. biloba 18' Spur longer, more than 3.9 in. (10 cm) long. 19 19(18') Inflorescences to 15.6 in. (40 cm) long; leaves to 8.6 in. (22 cm) long. A. coriacea 19' Inflorescences to 7.8 in. (20 cm) long; leaves to 4.3 in. (11 cm) long. A. somalensis 20(17') Inflorescences short, to 6.6 in. (17 cm) long. 21 20' Inflorescences longer, more than 7.8 in. (20 cm) long. 24 21(20) Dorsal sepal to 0.3 in. (0.8 cm) long. A. appendiculata 21' Dorsal sepal more than 0.5 in. (1.3 cm) long. 22 22(21') Leaves with blackish spots, to 9.4 in. (24 cm) long. A. confusa 22' Leaves without blackish spots, to 5.8 in. (15 cm) long. 23 23(22') Inflorescences short, to 3.1 in. (8 cm) long; dorsal sepal to 1.4 in. (3.5 cm) long. A. carnosa 23' Inflorescences longer, to 6.6 in. (17 cm) long; dorsal sepal to 1 in. (2.5 cm) long. A. kirkii 24(20') Dorsal sepal to 0.9 in. (2.2 cm) long. 25 24' Dorsal sepal more than 0.9 in. (2.2 cm) long. 32 25(24) Spur elongate, more than 4.9 in. (12.5 cm) long. 26 25' Spur shorter, to 4.7 in. (12 cm) long. 28 26(25) Leaves with undulate margins. A. verdickii 26' Leaves with straight margins. 27 27(26') Leaves with blackish spots (sometimes absent); lip long-acuminate. A. distincta 27' Leaves without blackish spots; lip acute. A. ellisii 28(25') Dorsal sepal to 0.8 in. (2 cm) long; inflorescences usually more than 4.7 in. (12 cm) long. 29 28' Dorsal sepal to 0.5 in. (1.4 cm) long; inflorescences to 4.7 in. (12 cm) long. 31 29(28) Leaves longer, to 7.8 in. (20 cm) long, with undulate margins; spur to 2.7 in. (7 cm) long. A. arachnopus 29' Leaves shorter, to 4.9 in. (12.5 cm) long, with straight margins; spur longer, more than 3.5 in. (1.4 cm) long. 30 30(29') Pedicel and ovary horizontal; spur gently curved at the base and then straight. A. decaryana 30' Pedicel and ovary suberect; spur gently curved for its entire length. A. stylosa 31(28') Spur to 2.3 in. (6 cm) long; leaves to 7.8 in. (20 cm) long; lip not auriculate. A. macrocentra 31' Spur to 3.1 in. (8 cm) long; leaves to 5.8 in. (15 cm) long; lip auriculate. A. mystacidii 32(24') Column elongate, to 1.4 in. (3.7 cm) long. A. gracillima 32' Column shorter, to 0.4 in. (1 cm) long. 33 33(32') Spur to 5.8 in. (15 cm) long. A. articulata 33' Spur longer, to 9.7 in. (25 cm) long. 34 34(33') Leaves with blackish spots. A. brachycarpa 34' Leaves without blackish spots. A. fuscata

Arends, J. C. and J. Stewart 1989. Aerangis gracillima: a definitive account of a rare African orchid of Cameroun and Gabon. Lindleyana 4(1):23-29; Chiron, G., I. La Croix and J. Stewart 1998. Two new species of Aerangis from tropical Africa. Orchid Rev. 106(1222):225-229 (reprinted in French in Orchid. Cult. & Protect. 36:6-12); Cribb, P. J. 1980. Barombia schliebenii, an extraordinary epiphytic orchid species from Central Tanzania. S. Afr. Orchid J. 11(4):110--114; Cribb, P. J. and J. Stewart 1983. Aerangis mooreana (Orchidaceae), an overlooked orchid. Orchid Rev. 91:218-219; Fibeck, W. and M. Dare 1997. Aërangis rusituensis, a new species from eastern Zimbabwe. S. Afr. Orchid J. 28(3):73-76; Fibeck, W. and V. Phiri 2000. Orchideen in Simbabwe: Aerangis-Verwandte. Die Orchidee 51(3):324-328; Hillerman, F. 1986. Growing Aerangis orchids. Amer. Orchid Soc. Bull. 55(8):803-807; Leroux, A. 1976. Barombia gracillima (Kraenzl.) Schltr. L’Orchidoph. 23:591-593; Leroux, A. 1989. Aerangis megaphylla Summerh. (Aerangis phalaenopsis). L’Orchidoph. 85:12; Leroux, A. 1989. Aerangis gravenreuthii (Krzl.) Schltr. L’Orchidoph. 85:22; Leroux, A. 1989. Aerangis collum-cygnii Summerh. L’Orchidoph. 88:182; Leroux, A. 1989. Aerangis kotschyana Reichb.f. L’Orchidoph. 88:182-183; Leroux, A. 1993. Aerangis stelligera Summerh. L’Orchidoph. 102:129-130; Leroux, A. 1996. Aerangis articulata (Rchb.f.) Schltr. L’Orchidoph. 121:79; Senghas, K. 1969. Aerangis buchlohii, eine neue Orchidee aus Madagaskar. Die Orchidee 20:12-16; Senghas, K. 1983. Aerangis seegeri, eine neue Orchidee aus Madagaskar. Die Orchidee 34(1):23-25; Stewart, J. 1977. The South African species of Aerangis. S. Afr. Orchid J. 8(4):113-118; Stewart, J. 1980. A revision of the African species of Aerangis (Orchidaceae). Kew Bull. 34:239-319; Stewart, J. 1986. Stars of the islands, a new look at the genus Aerangis in Madagascar and the Comoro Islands, 1. Amer. Orchid Soc. Bull. 55(8):792-802; Stewart, J. 1986. Stars of the islands, a new look at the genus Aerangis in Madagascar and the Comoro Islands, 2. Amer. Orchid Soc. Bull. 55(9):903-909; Stewart, J. 1986. Stars of the islands, a new look at the genus Aerangis in Madagascar and the Comoro Islands, 3. Amer. Orchid Soc. Bull. 55(10):1008-1015; Stewart, J. 1986. Stars of the islands, a new look at the genus Aerangis in Madagascar and the Comoro Islands, 4. Amer. Orchid Soc. Bull. 55(11):1117-1125; Stewart, J. and I. F. la Croix 1987. Notes on the orchids of southern tropical Africa, III. Aerangis. Kew Bull. 42(1):215-###.