Lindl.
Description
Dienia cylindrostachya is a terrestrial orchid distributed across the Himalaya and adjacent montane Asia, recorded from India, Nepal, Bhutan, China, Hong Kong, Myanmar and Pakistan, with GBIF documenting some 98 georeferenced occurrences. It favours humus-rich, shaded forest floors, mossy banks and damp grassy slopes in the temperate zone, typically between about 1500 and 3000 m. The photographed plant was found in West Nepal along the Suli-Khola at 2900 m in July, an elevation and season that coincide with its summer flowering during the monsoon, when soil moisture and atmospheric humidity are at a maximum.
The species is a small, glabrous herb arising from a fleshy, ovoid pseudobulb or thickened stem-base. It bears a few thin, plicate, ovate-elliptic to lanceolate leaves that are membranous and sheathing at the base. The inflorescence is an erect, slender, densely many-flowered cylindrical raceme, from which the epithet derives, carrying numerous minute, non-resupinate flowers in shades of greenish-yellow to purplish. The sepals and petals are small and spreading; the lip is broad, often auriculate or saccate at the base, and the column is short and stout. The fruit is a small, ellipsoid, ribbed capsule releasing dust-like seeds.
Long placed in Malaxis, the species is now treated in Dienia (Malaxidinae, Epidendroideae), a segregate distinguished by non-resupinate flowers and column structure. The family is rendered "Orchideaceae" in the source but the taxon belongs to the Orchidaceae. As an easily overlooked terrestrial of intact temperate forest, it is sensitive to deforestation, though its wide Asian range affords some resilience.
Author: Lindl. · Sources: POWO (Kew), GBIF, Flora of Nepal, Flora of China, Flora of Bhutan, Genera Orchidacearum (Pridgeon et al.)