Aerangis kirkii (Rchb.f.) Schltr., Beih. Bot. Centralbl. 36(2): 188 (1918).
Synonyms:
Angraecum bilobum var. kirkii Rchb.f., Gard. Chron., n.s., 18: 488 (1882).
Angraecum apiculatum var. kirkii (Rchb.f.) Rchb.f., Gard. Chron., n.s., 24: 456 (1885).
Angraecum kirkii (Rchb.f.) Rolfe in D.Oliver & auct. suc. (eds.), Fl. Trop. Afr. 7: 136 (1897).
Description:
Stem woody, 1-5 cm long, 3-5 mm diam., covered in closely overlapping leaf bases, with numerous flexuous greyish-white roots 1-2 mm diam. arising from the lower half. Leaves 2-7, very close together, oblanceolate or linear- lanceolate, the apex much dilated, and bilobed, the lobes rounded or acute, unequal, 4-12 mm long, dark greyish-green and leathery or dark green and slightly fleshy, up to 15 cm long, often much shorter, and up to 3 cm across at the widest part. Inflorescences one to several, arising below the leaves, bearing 2-6 flowers, usually horizontal or pendulous, up to 17 cm long; peduncle terete, up to 6 cm long, 1-3 mm diam. bearing 1-3 tight sheaths; rhachis straight, slightly wider below each bract, greyish-pink; bracts broadly triangular, acute, 4-8 mm long. Flowers spreading, 1-5-3 cm apart, closer together towards the tip of the inflorescence, the apical one opening first and somewhat larger than the lower ones, white, with pink tinges in the spur; pedicel with ovary 18-25 mm long. Dorsal sepal erect, ovate-lanceolate, acuminate, 18-25 x 5-7 mm; lateral sepals longer and narrower, spreading, lanceolate, acuminate, 22-28 mm x 4-6 mm. Petals usually spreading, sometimes slightly reflexed, oblanceolate, acuminate, 16-20 x 5-6 mm. Lip oblong then acuminate or apiculate, 16-20 x 7-8 mm; spur pendulous, often curving forwards, slightly inflated in the lower half, narrowing again towards the tip, 6-7-5 cm long. Column 4 mm long, lower surface sloping and dilated; anther cap shortly beaked; rostellum straight, almost reaching across the mouth of the spur; pollinia globose; stipes rather broad; viscidium ovate with the margins curving over the rostellum. Capsule 4-8 cm long, up to 5 mm diam.
Habitat:
Coastal bush and riverine forest at low altitudes inland, on small trees and bushes, usually in rather dense shade; 0-450 m.
Cultivation:
As given for the genus.
Notes:
This species was originally described as a variety of Angraecum bilobum Lindl. by Reichenbach who had seen plants both newly collected and grown in cultivation for a number of years. He noted that plants collected in the wild had very distinctive leaves, which were very narrow but suddenly dilated at the apex into two unequal, rounded lobes. After some while in cultivation the leaves became much broader and this made him think that the plant might be just a starved form of the well known species from West Africa. Much more material has now been collected, particularly from Tanzania, and it is apparent that the leaves are somewhat variable, even in the wild. They may be dark green or greyish green in colour, with conspicuous venation.
Apart from the leaves, this species can also be distinguished from A. biloba by the fact that it bears far fewer, but larger flowers with differently shaped tepals. Like A. biloba, and several Madagascan species of this genus (Aerangis stylosa, Aerangis articulata, Aerangis modesta), the apical flower of the inflorescence opens first and is larger than all the others. As pointed out by Schlechter (1918) this species now seems to be most closely related to Aerangis gravenreuthii. The flowers of the two species are very similar, but in the specimens that I have examined closely the lip is wider and more suddenly and sharply acuminate in Aerangis kirkii. In most specimens of Aerangis kirkii the leaves are the distinctive character that clearly separates this species from all others in the genus.
Distribution:
Kenya to S. Africa
References:
Encylopedia of Cultivated Orchids Hawkes 1965 as Aerangis biloba var kirkii; Orchids of East Africa Piers 1968; An Introduction to the Cultivated Angraecoid Orchids of Madagascar Hillerman & Holst 1986; Miniature Orchids Northern 1988; Flora of Tropical East Africa Orchidaceae Part 3 Cribb 1989; Manual of Cultivated Orchids Bechtel, Cribb, Laurent 1992; Manual of Orchids Stewart 1995; Orchids Of Kenya Stewart 1996; African Orchids in the Wild and Cultivation La Croix 1997; Botanica's Orchids Laurel Glenn 2002; AOS Bulletin Vol 73 No 12 2004; Angraecoid Orchids Stewart, Hermans, Campbell 2006; A Revision of the African Species of Aerangis (Orchidaceae) Kew Bulletin, Vol. 34, No. 2 (1979), pp. 239-319; WCSP (2017). 'World Checklist of Selected Plant Families. 19.01-2017; http://apps.kew.org/wcsp/
Images:
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| In culture |
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| Photograph© Lourens Grobler. Image used with kind permission. |
