Cynorkis aconitiflora Hermans, Andriant. & Sieder, Kew Bull. 72(3)-38: 2 (2017).
Description:
Erect to semi-erect terrestrial herb, up to 40 cm tall, including the inflorescence. Tuber characteristics not known. Stem up to 4 cm long, 5 - 6 mm in diam., enveloped by a thin brown basal sheath, up to 33 mm long, 7 mm wide, with a pair of almost opposite leaves above. Leaves pale green, more or less spotted with dark red, margins of young leaves purple, ovate-lanceolate, acuminate, up to 15 cm long, 4 cm wide. Inflorescence pale green, glabrous, spotted purple-red longitudinally, emerging from the centre of the leaf petiole, up to 35 cm, c. 4 mm in diam., 2 - 3 lanceolate sheaths enveloping the peduncle, c. 20 mm long; rachis 8 - 12 cm, densely 12 - 26-flowered, unilateral; floral bracts amplexicaul at the base, acuminate, apiculate at the apex, green with a purple margin and tip, 12 - 16 mm long, 2.5 - 3.5 mm wide; pedicel and ovary glabrous, 12 - 14 mm long, 1.5 - 1.7 mm wide, pale green with pale purple bands, curved. Flowers overall c. 11 mm long, 10 mm wide, glabrous, petals and sepals purple, the petals a little paler, lip pale purple with a slightly darker longitudinal central ridge, the base and part of the lateral lobes white, spur paler purple, rostellum white. Dorsal sepal forming a tight hood with the petals, deeply concave, base inflated, the apex slightly recurved, 6.8 - 7.1 mm long, 3.3 - 3.6 mm wide; lateral sepals spreading and somewhat recurved, oblong-obovate 8.9 - 9.2 mm long, 4.9 - 5.2 mm wide. Petals appressed to the inside of the dorsal sepal margins, narrowly oblong-obovate, the margins a little undulate, 7.3 - 7.5 mm long, 2.0 - 2.2 mm wide. Lip 3-lobed, overall 10.4 - 10.7 mm long, 5.3 - 5.9 mm wide, the lateral lobes small, triangular, curved upwards, mid-lobe linguiform, concave with a longitudinal raised central ridge; spur basally infundibuliform and parallel with the ovary then narrowed, somewhat descending and rounded, 8.1 - 8.3 mm long, 1.5 - 1.6 mm in the middle. Column in a horizontal plane 4.1 - 4.9 mm long 3.1 - 3.3 mm wide, with two long rostellum arms surpassing the nose-like midlobe by double the length of the rostellum, staminodes short, rounded, verrucose; anther loculi erect; pollinia including the thin caudicle c. 4 mm long.
Etymology:
The species name refers to the resemblance of flower shape and colour to the Monkshood, Aconitum napellus L. (Ranunculaceae).
Habitat:
Terrestrial in the shade of small trees and ferns amongst rocks in seasonally very dry forest remnants within grassland on basement rock, around 900 m.
Notes:
The new species is characterised by the two-leaved plant with dark spots on the young leaves, peduncle and long floral bracts. The dense unilateral raceme carries up to 26 flowers. The medium-sized glabrous flowers have a distinct 3-lobed lip with the basal lobes small and triangular, the mid-lobe tongue-shaped with a thick central ridge, the spur which is at first wide and then narrows into a thinner tube. With its secund rachis and 3-lobed lip the new species bears some similarity to Cynorkis lilacina Ridl. (Ridley 1885: 515) in section Hemiperis, from highland Madagascar but it has two larger leaves, longer floral bracts, glabrous rather than hirsute flowers and a lip of different proportions (up to 8 x 7 mm, vs 10 x 6 mm in the new species) with upturned side lobes. It is similar to Cynorkis lemurica Bosser (2015: 20) in section Gibbosorchis from the same area but at a higher elevation than the new species. It also differs in its ovate-lanceolate rather than linear leaves, a unilateral rachis, floral bracts almost as long as the ovary, a larger lip (up to 7.5 x 5 mm in Cynorkis lemurica vs up to 10.7 x 5.9 mm in the new species), verrucose staminodes and purple rather than whitish-pink flowers.
Cultivation:
As given for the genus.
Distribution:
So far only known from a small locality 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
