Angraecum lanceolatum Ječmenica, Stévart & Droissart, sp. nov.
Description:
Small epiphytic herbaceous plant. Stem hanging, slightly zig-zag in form, unbranched, up to 8.5 cm long. Leaves alternate, spaced, narrowly ovate to lanceolate, sometimes slightly falcate and always convolute in the distal part, margins entire; distinct midvein forming slight channel, accompanied with 2 or 3 nerves on each side merging into one throughout; small stomata spots visible in young leaves; leaf apex unequally bilobed, acuminate, with the larger lobe 1.5–2.8 mm long and the smaller 0.3–1.2 mm long, leaf blade 2.3–4.1 × 0.6–0.9 cm; leaf internode about 5–6 mm long. Inflorescence single flowered, eventually two-flowered; peduncle elongated 13–23 mm long, opposite to the leaf at the node. Bracts acute, 2 mm long. Flowers white, opening diameter about 12.5 mm. Ovary and pedicel not resupinate, 8 mm long. Dorsal sepal 6.2–8.5 × 3 mm, elliptic, acute, thick, with entire margins. Lateral sepals 6–7 × 2–2.2 mm, elliptic, acute, thick, with entire margins. Petals 5–6.5 × 2–2.2 mm, obliquely elliptic, acute, entire margins, similar in shape to lateral sepals. Lip 5–6 × 4.5–5 mm, concave, rhombic when flattened, widest between first third and the half, acute; spur 16–19.5 mm, cylindric, slender, straight, somewhat elliptically inflated and greenish at the apex. Column 1.5 × 2 mm. Pollinia 2, pyriforme. Fruit capsule, 18–24 × 3.5–5 mm.
Etymology:
The specific epithet of the new species owes to the particular leaf shape. Even though there are several interpretations of "lanceolate" shape according to different authors (Linnaeus, Lindley), we relied on the current depiction from Beentje (2010) that describes it as narrowly ovate and tapering to a point at the apex.
Habitat:
The specimen collected in Cameroon was found at 850 m elevation in submontane forest with Gilbertiodendron unijugum (Pellegr.) J. Léonard (Fabaceae). The plant was epiphyte at about 1.5 m from the ground, on the trunk of a shrub with a diameter less than 10 cm.
Phenology:
Flowering occurs in June and September.
Note:
Angraecum lanceolatum is close to A. stolzii Schltr. (1915) but differs from it by shorter narrowly ovate leaves that convolute in the distal half, by a shorter zig-zag stem and by a rhombic lip shape. The species also resembles A. cultriforme Summerh. (1958) but differs from it by smaller flower size and slightly curved spur. Angraecum lanceolatum is also close to A. pyriforme Summerh. (1936) in the shape of floral parts, but differs from it by previously stated vegetative characters, hanging habit, single-flowered inflorescence and smaller flower.
References:
Taxonomy of Atlantic Central African orchids 5. A new species of Angraecum sect. Conchoglossum (Orchidaceae, Angraecinae) from Gabon and Cameroon. PhytoKeys 61: 61-71 (25 Feb 2016)
