O.E.Schulz
Description
Arcyosperma primulifolium is a Himalayan crucifer of high-elevation forest and meadow margins, with GBIF recording 99 occurrences from India, Nepal, Pakistan and Bhutan. It occupies moist, shaded slopes, forest edges and damp turf in the upper temperate to subalpine zone, often among rocks and along the transition between birch-rhododendron forest and open alpine pasture. The image was taken at Kinkhola in Garhwal, India, at about 3500 m in June, when the plants flower as the high meadows green up after the spring thaw.
It is a perennial herb with a stout rootstock from which arise a rosette of long-petioled, lyrate to pinnatifid basal leaves; the lamina, with its rounded, crenate terminal lobe, recalls the foliage of a primrose, as the epithet primulifolium notes. The flowering stems are erect and bear smaller, less divided leaves below an elongating raceme. The flowers are white, with four sepals, four clawed petals and the tetradynamous stamens of the Brassicaceae. The fruit is a slender, somewhat flattened silique that distinguishes the monotypic genus; the seeds are arranged in the pod in the manner reflected by the generic name Arcyosperma.
Arcyosperma (Brassicaceae) is a monotypic genus segregated by O. E. Schulz, restricted to the Himalaya and allied within the family's diverse Asian montane crucifers. Its distinctive lyrate leaves and fruit characters set it apart from related genera such as Cardamine and Draba with which it co-occurs. Being a narrow-ranged montane endemic of a single species, it is of particular taxonomic and biogeographic interest, and like other high-Himalayan herbs its populations depend on intact subalpine forest and meadow habitats.
Author: O.E.Schulz · Sources: POWO (Kew), GBIF, Flora of Pakistan, Annotated Checklist of the Flowering Plants of Nepal, Jafri's Flora of West Pakistan (Brassicaceae), Schulz's treatment of Cruciferae in Engler's Das Pflanzenreich