Cynorkis siederi Hermans & Andriant., Kew Bull. 72(3)-38: 18 (2017).
Description:
Erect terrestrial herb, up to 20 cm high including inflorescence, forming small clumps of several plants. Tubers 1 - 2, elongate, surface woolly, c. 30 mm long, 7 mm wide, roots, fleshy, glabrous c. 2 mm in diam. Stem very short, c. 4 mm in diam., enclosed by a thin greenish-brown scarious sheath, with a single almost erect radical leaf. Leaf and sheaths green, somewhat fleshy, shiny on top, conduplicate, long-lanceolate, acuminate, up to 18 cm long, 12 mm wide. Inflorescence emerging from the leaf axil, up to 19 cm, 1.5 - 1.8 mm in diam., green, glabrous, with a long leaf-like lanceolate-subulate sheath c. 4 cm above the leaf base, 85 - 92 mm long, 3 - 4 mm wide, a second sheath about half way up the inflorescence of the same shape but shorter, 21 - 24 mm long, 2 - 3 mm wide; rachis sub-umbellate, up to 5 flowers; floral bracts green, ovate-lanceolate 12 - 14 mm long, 2.5 - 3 mm wide; pedicel and ovary carrying a few scattered hairs, mainly in the upper half, green, almost straight, up to 25 mm long, 2 mm wide. Flowers overall 18 - 20 mm long, 14 - 16 mm wide, not including the spur, sepals greenish white with the veins green, brownish at the tip, petals white with a pale lilac margin, lip white with two pale lilac lines towards the base, spur white becoming green in the lower half, column greenish-white the pollinia brown, exterior of sepals with a densely pilose indumentum on the exterior. Dorsal sepal forming a hood with the petals, ovate, deeply concave, 7.0 - 8.2 mm long 3.2 - 3.4 mm wide; lateral sepals spreading, oblong-obovate, curved apically, 8.1 - 8.3 mm long, 3.1 - 3.2 mm wide. Petals loosely attached to the dorsal sepal margins, ovate, 7.9 - 8.1 mm long, 3.9 - 4.1 mm wide. Lip with two large and spreading lateral lobes with a gutter-like depression in between, a broadly notched to bilobed central lobe, overall 13.1 - 14.4 mm long, 10.5 - 11.1 mm wide, the lateral lobes almost oval, the margins a little undulate, the lateral lobes much smaller with distinct sinuate to serrate margins; spur pendent then incurved in the lower quarter, subulate towards the end, up to 32 mm long, c. 1 mm in diam. Column in an almost horizontal plane 5.2 - 5.4 mm long 4.5 - 4.8 mm wide, with two short rostellum arms for almost half its length, with a distinct recurved bilobed midlobe forming a snout-like protrusion, staminodes below the base of the rostellum arm forming verrucose auricles, anther loculi incurved, pollinia including the caudicle c. 4.5 mm long.
Etymology:
Named for Anton Sieder, of the Botanical Gardens, University of Vienna, Austria who discovered the new species.
Habitat:
Water seepage areas on basement basalt rock, amongst large rocks in crevices and shallow pockets of humus and other detritus in seasonally very dry forest remnants within grassland, around 600 m, growing sympatrically with Cynorkis christae and Cynorkis lentiginosa.
Notes:
The species is distinct by its somewhat fleshy, long lanceolate single leafand a long thin leaf-like lower peduncle sheath. The medium-sized flowers, which are almost completely white, have a distinct lip with two large rounded lateral lobes and a smaller divided mid-lobe with more or less serrate margin. The snout-like mid-lobe of the rostellum is unusual in Cynorkis. In overall plant habit it resembles Cynorkis uniflora Lindl. (Lindley 1835: 331) in section Gibbosorchis, but its flowers have a completely different shape, size and colour. It is probably nearest to Cynorkis speciosa Ridl. (Ridley 1886: 122) in section Gibbosorchis, a widespread and variable species, but it has side lobes to the lip that are larger than the divided midlobe (vs almost equal in Cynorkis speciosa), a straight and longer spur (vs inflated a little in the middle in Cynorkis speciosa), distinctly shaped and coloured mid-lobe of the rostellum. Its lip and spur are similar to those of Cynorkis aphylla Schltr. (Schlechter 1913: 150) in section Lowiorchis, but apart from the flower colour (dark pink in Cynorkis aphylla) the leaves are not generally developed at flowering time and are broadly oblong (vs lanceolate in Cynorkis aphylla).
Cultivation:
As given for the genus.
Distribution:
Known only from a small area in the Antsahabe area in Northern Madagascar.
References:
New species and nomenclatural changes in Cynorkis (Orchidaceae: Orchidoideae) from Madagascar and the Mascarenes, KEW BULLETIN (2017) 72: 38
