Angraecum inflatum Hermans, Kew Bull. 76: 513 (2021).
Description:
Pendent to arching, tufted epiphytic herb up to 18 cm long, loosely attached to the substrate and forming large overlapping colonies along the mossy substrate; with an extensive mass of branched, wiry, smooth to slightly verrucose basal roots, c. 1 mm in diam. Stem branching from the base and rarely re-branching, up to 17 cm long, 4 - 6 mm wide, more or less flattened, completely covered by winged leaf sheaths with erose to lacerate, recurved apical margins, the base and withered stems covered by grey corrugate leaf sheath remnants. Leaves succulent, alternate-distichous along the stem, twisted at the base to almost lie in one plane, elliptic to narrowly ovate, 15 - 19 x 5 - 7 mm, elliptic in cross-section, with a canaliculate mid-vein, round underneath, obtuse to rounded at the base, unequally roundly bilobed at the apex, pale to dark green, sometimes becoming orange-brown with age. Inflorescence from the axis of the leaf sheaths, very short, generally single-flowered, leaf-opposed; sometimes with a second flower from the same axis. Peduncle very short, angular in cross-section, c. 0.3 - 0.5 x 0.2 mm, covered by 1 - 3 thin sterile bracts. Floral bracts thin, ovate, conduplicate, dorsally ridged, apiculate, 1.8 - 2.1 x 1.2- 1.5 mm, pale brown. Pedicel and ovary fusiform, 2 - 3.2 x 0.7 - 0.9 mm, with a few brownish black verrucae along the longitudinal furrows. Flowers generally resupinate, overall 6 - 7x5 - 7 mm diam., pale greenish-yellow, the spur, column and ovary pale green. Dorsal sepal ovate, 2.8- 3.8 x 1.5 - 1.8 mm, acuminate, thickened at the apex, recurved in the apical half. Lateral sepals, ovate, acuminate, thickened at the apex, 3.2 - 4 x 1.2 - 1.7 mm, spreading, recurved. Petals ovate, acuminate, 2.3 - 3.4 x 0.9 - 1.3 mm. Lip deeply concave, elliptic, acuminate, the apical margin thickened-incurved, with a short longitudinal callus at the base, 2.5 - 3.2 x 1.5 - 1.8 mm, spur opening narrow, cylindrical at the base then ampulliform, more or less flattened against the substrate, 1.6 - 2.3 x 1 - 1.2 mm. Column very short, rounded, with distinct dolabriform lateral rostellum lobes folded in front of the distal part, apex of rostellum deeply emarginate with a small rounded central lobe, c. 1 x 1 mm, stigma transversely elliptic. Anther cap transversely elliptic in outline, with a raised rounded lobe, 0.4 - 0.7 x 0.5 - 0.8 mm; pollinia 2, obovoid, c. 0.2 x 0.3 mm, indistinct stipes and a small viscidium c. 0.1 mm long. Fruit c. 6 x 4 mm, subglobose to ovoid, roundly ridged, maturing as other flowers develop.
Etymology:
The epithet name refers to swollen leaves, lip margin and puffed-up spur.
Recognition:
Angraecum inflatum fits well in sect. Lemurangis Garay which is characterised by the long stem, distichous leaves, few-flowered inflorescences shorter than the leaves and short rachis. It is distinct in having short fleshy ovoid leaves, winged stem sheaths with an erose-lacerate apical margin, inflorescences with a very short peduncle, and flowers with a lip with thickened margins, a small longitudinal callus at the base and an ampulliform spur and the capsule maturing as other flowers develop.
Habitat:
Sclerophyllous woodland and forest remnants, on Ficus and other small trees. Altitude 1200 -1700 m.
Notes:
Angraecum inflatum is most similar to A. baronii (Finet) Schltr. from Madagascar but in that species the stem is more extensively branched, the leaves are narrowly lanceolate (vs ovate) and the apex attenuate (vs rounded); the peduncle is about twice as long; and
the flowers are similar in size but the lip is more acuminate and thin towards the apex and the spur is cylindrical and curved at the apex (vs ampulliform). It is also similar to A. costatum Frapp. in Cordem. from Réunion but in that species the plant is more erect with slightly longer and less succulent leaves; the flowers are a little larger and the spur about twice as long; the lip lacks a basal callus and the spur is slightly swollen towards the apex (vs ampulliform).
Distribution:
Madagascar. Endemic to Fianarantsoa province in central Madagascar.
References:
Angraecum inflatum, a new species in Angraecinae (Orchidaceae) from Madagascar by Johan Hermans, Landy Rajaovelona & Phillip Cribb. Kew bulletin (2021) Published online 24 August 2021; POWO (2022). "Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; http://www.plantsoftheworldonline.org/ Retrieved 21 November 2022."
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