(Wall. ex Edgew.) C.-A.Jansson
Description
Rosularia adenotricha (Wall. ex Edgew.) C.-A.Jansson is a succulent rosette-forming herb of dry rocky slopes and cliff crevices in the western and central Himalaya and adjacent mountains. GBIF records span India, Pakistan, Afghanistan, Nepal and Bhutan, with scattered occurrences eastward to Myanmar and Thailand and west to Oman, totalling some 200 collections. It is a chasmophyte of warm, well-drained, often sun-exposed rock faces and gravelly banks, typically from low and middle elevations into the subalpine zone; the illustrated material was gathered in Bhutan at Anthso, 980 m, in October, near the lower end of its altitudinal range.
The plant develops compact basal rosettes of fleshy, obovate to spathulate leaves that are densely covered with glandular (adenose) hairs, giving a viscid, greyish-green appearance and accounting for the epithet adenotricha. From the rosette arises an erect, glandular-pubescent flowering stem bearing a cymose or thyrsoid inflorescence. The flowers are 5(–7)-merous with narrow, erect to slightly spreading petals fused only at the base, whitish to pale yellow often flushed pink, the stamens twice as many as the petals; nectar scales subtend each carpel. The fruit is a group of erect, many-seeded follicles.
Rosularia (subfamily Sempervivoideae) is a small Old World genus close to Sempervivum and Prometheum, distinguished by its campanulate, basally connate corolla. The species has been treated under several combinations, reflecting unsettled generic limits within the Sempervivum alliance. As a widespread rock-dwelling succulent it is not considered threatened, though its glandular indumentum makes it a distinctive element of arid Himalayan cliff floras.
Author: (Wall. ex Edgew.) C.-A.Jansson · Sources: POWO (Kew), GBIF, Flora of Pakistan, Flora of Bhutan Vol. 1, Flora of Nepal, Jansson: Studies in Rosularia (Sempervivoideae)