Angraecum inflatum Hermans

Hermans, J., Rajaovelona, L. & Cribb, P. Angraecum inflatum, a new species in Angraecinae (Orchidaceae) from Madagascar. Kew Bull 76, 513–517 (2021). DOI: https://doi.org/10.1007/s12225-021-09960-5

Type

Type: Madagascar, Fianarantsoa prov., Ankazomivady area, c. 1500 m, cult. Malala Orchidées, 1999, Hermans 4935 (holotype K!).

Morphology General Habit

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

Morphology Leaves

Leaves succulent, alternate-distichous along the stem, twisted at the base to almost lie in one plane, elliptic to narrowly ovate, 15 – 19 × 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

Morphology Reproductive morphology Inflorescences

Inflorescence from the axis of the leaf sheaths, very short, generally single-flowered, leaf-opposed; sometimes with a second flower from the same axis

Morphology Reproductive morphology Inflorescences Peduncles

Peduncle very short, angular in cross-section, c. 0.3 – 0.5 × 0.2 mm, covered by 1 – 3 thin sterile bracts

Morphology Reproductive morphology Inflorescences Bracts

Floral bracts thin, ovate, conduplicate, dorsally ridged, apiculate, 1.8 – 2.1 × 1.2 – 1.5 mm, pale brown. Pedicel and ovary fusiform, 2 – 3.2 × 0.7 – 0.9 mm, with a few brownish black verrucae along the longitudinal furrows

Morphology Reproductive morphology Flowers

Flowers generally resupinate, overall 6 – 7 × 5 – 7 mm diam., pale greenish-yellow, the spur, column and ovary pale green

Morphology Reproductive morphology Flowers Calyx

Lateral sepals, ovate, acuminate, thickened at the apex, 3.2 – 4 × 1.2 – 1.7 mm, spreading, recurved Dorsal sepal ovate, 2.8 – 3.8 × 1.5 – 1.8 mm, acuminate, thickened at the apex, recurved in the apical half

Morphology Reproductive morphology Flowers Corolla

Petals ovate, acuminate, 2.3 – 3.4 × 0.9 – 1.3 mm

Morphology Reproductive morphology Flowers Labellum

Lip deeply concave, elliptic, acuminate, the apical margin thickened-incurved, with a short longitudinal callus at the base, 2.5 – 3.2 × 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 × 1 – 1.2 mm

Morphology Reproductive morphology Flowers Column

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 × 1 mm, stigma transversely elliptic. Anther cap transversely elliptic in outline, with a raised rounded lobe, 0.4 – 0.7 × 0.5 – 0.8 mm; pollinia 2, obovoid, c. 0.2 × 0.3 mm, indistinct stipes and a small viscidium c. 0.1 mm long

Morphology Reproductive morphology Fruits

Fruit c. 6 × 4 mm, subglobose to ovoid, roundly ridged, maturing as other flowers develop

Distribution

Madagascar. Endemic to Fianarantsoa province in central Madagascar.

Ecology

Sclerophyllous woodland and forest remnants, on Ficus and other small trees. Altitude 1200 – 1700 m.

Conservation

Angraecum inflatum is endemic to Madagascar, restricted to the Amoron’i Mania region (Fianarantsoa province). The type locality is now being cleared for charcoal and the cultivation of Pelargonium, grown increasingly in the region to produce essential oils. The two collections with the recent observations represent a total of two ‘locations’ (sensu IUCN 2012) with respect to the main threat, which is shifting agriculture. With the observations and the two collections outside the protected areas, we infer that the destruction of the habitat will induce a strong continuous decline in the area of occupancy (AOO), habitat extent and quality, the number of subpopulations and mature individuals in the next ten years. Angraecum inflatum is therefore assessed as Endangered (EN) under criterion B2ab (i, ii, iii, iv, v).

Phenology

December to February.

Etymology

The epithet name refers to swollen leaves, lip margin and puffed-up spur.