Angraecum aloifolium Hermans & P.J.Cribb

in Orch. Rev. 105. 1214: 108 (1997).

Synonymes

Humblotiangraecum aloifolium (Hermans & P.J.Cribb) Szlach., Mytnik & Grochocka in ref. [356]P.15

Répartition

Madagascar.

Floraison : ________S___.

Description

Hermans & Cribb)A medium sized erect epiphytic herb, 60 to 105 mm. long. Stem simple, short, stout, 9 to 15mm in diameter, covered in persistent scarious leaf-sheaths below. Roots 1mm. in diameter, smooth, white and wiry. Leaves distichous, narrowly ensiform, spreading, fleshy-coriaceous, triangular in cross section, canaliculate, 42 to 50mm long, 10 to 12 mm. broad, 7mm. wide at the top, pale green, surface pitted and fissured with dark green crevices. Inflorescence 1- to 2-flowered, porrect, axillary; peduncle, fleshy, round and short, 4 to 6 mm, partly concealed by 1 or 2 bracts; bracts 4-5mm long. Flowers 35-45 mm high, 52 mm. deep including curved base of spur, sepals white-yellow becoming green towards the column, petals, lip and spur white, column green; pedicel 6mm long; ovary 65-66mm long, triquetrous becoming bilaterally compressed, green speckled with whitish green towards the apex. Dorsal sepal 22 to 25mm long, 6 to 7mm wide, lanceolate, acuminate, dorsally strongly keeled. Lateral sepals 23 to 25mm long, 6 to 7mm wide, lanceolate, acuminate, dorsally strongly keeled. Petals 17 to 20mm long, 6 to 7mm wide, lanceolate, acuminate, slightly ridged in centre. Lip 49 to 52 mm long, 15 to 20mm wide (including base of spur), strongly dilated at the base, concave, elliptic, acute, finely 8- to 15-veined, central vein slightly more prominent; spur 80 to 98 mm long, funnel-shaped and erect at base, filiform (1.5mm.) and acutely decurved in lower two thirds. Column short and stout, 5mm long, 5mm broad, cleft in front, rostellum bifid; pollinia 1mm in diameter, waxy. Fruit 15 mm long, 5 mm in diameter, dark green extensively spotted with pale green flecks.Although Angraecum aloifolium has flowers that are similar in shape to those of Angraecum compactum Schltr. and Angraecum equitans Schltr., both in the section Perierangraecum, its affinities more probably lie with Angraecum leonis (Rchb.f.) André in section Humblotiangraecum. It differs from the first two in its leaf and peduncle type, in having a peduncle which is incompletely covered by bracts, its lip shape, the more pronounced kink in the spur and other structural differences in sepals and petals. Its similarity to A. leonis lies in their sharing succulent leaves, a concave lip shape, the absence of a pronounced ridge on the lip, and the shape of the spur.A similar ambiguity is evident with Angraecum urschianum Toilliez-Genoud & Bosser; which has the overall floral structure of sect. Perrierangraecum but an exposed pedicel which places it outside the section, a discrepancy which was also mentioned by the authors in its description (Toilliez-Genoud & Bosser, 1961). Angraecum urschianum is similar in vegetative morphology to the new species but differs by its much smaller size both florally and vegetatively: the following measurements being recorded for Angraecum urschianum: leaves -12 × 4 mm., plant - 30mm., flower - 14 × 8mm., (flower and spur shape are also distinct.). Schlechter (1925) was the first to recognise sections Perrierangraecum and the Humblotiangraecum. He was followed in this by Perrier (1939-41) in the Flora of Madagascar - Orchidees and by Garay (1973.).

Bibliographie

David Du Puy, Phillip Cribb, Jean Bosser, Johan & Clare Hermans. The orchids of Madagascar. Royal Botanic Gardens, Kew. 1999. Page 21. Photo.

Joyce Stewart, Johan Hermans & Bob Campbell. Angraecoid orchids. Timber Press. 2006. Page 49. Photo.

David Du Puy, Phillip Cribb, Jean Bosser, Johan & Clare Hermans. Orchids of Madagascar. Second edition. Royal Botanic Gardens, Kew. 2007. Page 29. Photo.

Phillip Cribb & Johan Hermans. Field guide to the orchids of Madagascar. Kew Publishing. 2009. Page 332. Photo.

Jean Bosser & Marcel Lecoufle. Les orchidées de Madagascar. Biotope. 2011. Page 113. Photo.


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