Sprague
Description
Incarvillea younghusbandii is a dwarf, ground-hugging alpine herb of the high Tibetan plateau and the adjoining Himalaya, recorded from China (Xizang), Nepal and Bhutan with about 180 GBIF occurrences. It is a specialist of cold, arid to semi-arid high-elevation habitats: gravelly flats, stony alpine steppe, sandy river terraces and screes, typically between roughly 3,600 and 5,000 m. The plant documented at Phoksundo Lake in West Nepal at 3,650 m, flowering in July, sits near the lower edge of its range and illustrates its association with the dry, rain-shadowed inner Himalayan valleys that grade into the Tibetan plateau flora.
The plant is a stemless or nearly stemless perennial arising from a thick, fleshy taproot. The leaves form a flat basal rosette and are pinnately or pinnatisect-compound with rounded, crenate leaflets, often somewhat fleshy and pressed close to the ground. The flowers are large and showy relative to the diminutive plant, borne almost sessile within the rosette; the corolla is broadly funnelform to trumpet-shaped, rose-pink to magenta with a paler or yellowish throat, weakly bilabiate with five spreading rounded lobes. The fruit is an elongate, beaked, dehiscent capsule releasing flattened, winged or hairy-margined seeds.
The rosette-and-taproot habit is a classic adaptation to the wind-blasted, frost-prone, short-season conditions of the plateau, minimising exposure while presenting flowers at ground level to insect pollinators. Incarvillea is the principal temperate Asian genus of the otherwise largely tropical Bignoniaceae, and this species belongs to its specialised high-alpine, acaulescent group. Though not formally assessed, its restricted habitat warrants attention.
Author: Sprague · Sources: POWO (Kew), Flora of China Vol. 18, Flora of Bhutan Vol. 2, GBIF, Grierson: Bignoniaceae revisions of the eastern Himalaya