AFRICAN

ORCHIDS

Platanthera pollostantha R.M.Bateman & M.Moura, PeerJ 1(e218): 60 (2013).
Description:
Short-spurred Butterfly-orchid: Tubers broadly fusiform, narrowing to a single, long, fleshy apical root; a further 2–4 roots emerge horizontally from the base of the stem; old and new tubers separated by a substantial stolon 30–50% the length of the tuber. Stem 25 ± 17cm, 2.9 ± 2.0 mm in diameter. Sheathing leaves usually 2, largest 105 ± 73 mm × 31 ± 30 mm, broadly ovate/obovate, usually spreading and rarely with elongate petiole; bracteoidal leaves 4.1 ± 3.0, usually distributed fairly evenly along stem and grading into basal bracts. Inflorescence 77 ± 56 mm, 40 ± 36 flowers (19 ± 16 fls/cm). Basal bracts 27 ± 39 mm, floral bracts 10 ± 7 mm × 3.5 ± 2.0 mm, lanceolate; marginal cells rounded, 53 ± 24 µm in longitudinal diameter. Flowers uniformly schiele’s green to pea green (RHS 143C–144B in natural light, 149A in artificial flash); median sepal and lateral petals connivent over gynostemium. Labellum occasionally paler towards spur entrance, entire, 2.9 ± 1.4 × 2.1 ± 0.7 mm, elliptic-ovate, held vertically or more often projecting slightly backward but also usually curved gently backward. Spur 3.1 ± 0.8 mm long × 0.8 ± 0.5 mm in diameter at mouth, 0.8 ± 0.3 mm midway along its length, strongly down-curved; spur entrance strongly compressed vertically. Ovary 8.4 ± 3.6 mm. Lateral sepals oriented closer to horizontal than vertical, 3.4 ± 1.4 × 2.3 ± 0.7 mm. Lateral petals 2.3 ± 1.2 mm. Gynostemium 1.3 ± 0.5 mm long × 1.4 ± 0.5 mm wide; stigma immediately above spur entrance, a horizontally elongate oblong, at most 0.8 ± 0.6 mm wide; rostellum a subdued, near-horizontal ledge; auricles lateral to, and largely fused with, gynostemium, small, 0.5 ± 0.2 mm. Anther locules linked by a narrow, well-developed connective, locule aperture ± linear, relaxed; paired pollinaria 0.9 ± 0.4 mm, slightly to moderately convergent from viscidium to pollinium apex, viscidia separated by 0.8 ± 0.3 mm, apices of pollinaria by 0.5 ± 0.3 mm; viscidia pendent, angled inwards but not opposed, near-equidimensional, obscurely bipartite; caudicle near-linear, strap-like, much shorter than the pale yellow pollinium; pollinium bears few vertical rows of massulae. Fragrance strong, almost resinous, of musk and spice.
Etymology:
Novel epithet derived from the Greek pollostos (smallest, least) and anthos (flower), reflecting the fact that the flowers of this species are even smaller than those of P. micrantha.
Habitat:
Most frequent in laurisilva scrub, rough grassland above lavas and alpine grassland; also found in rough pastures, oakwoods and Cryptomeria plantations; (250–)400–1000(–1300) m asl.
Distribution:
Azores
References:
Systematic revision of Platanthera in the Azorean archipelago: not one but three species, including arguably Europe’s rarest orchid by Richard M. Bateman,corresponding author Paula J. Rudall, and Mónica Moura