(L.) Lehm.
Description
Trichodesma indicum (L.) Lehm. is a herb of the borage family widespread across the Old World tropics and subtropics, native through India, Pakistan, Nepal, Sri Lanka and Myanmar and extending to Southeast Asia, Africa and Australia, with over 1150 GBIF occurrences. It is a weedy plant of open dry ground, fallow fields, roadsides, wastelands and gravelly slopes, typically at low elevations but ascending in the inner Himalayan valleys. In western Nepal it was recorded at Hurikot at 2700 m in June and at nearby Hanke at the same elevation in July, an unusually high station reflecting warm, dry rain-shadow habitats in the upper Karnali region.
It is an erect, branching annual covered throughout with stiff, bulbous-based bristly hairs giving a harsh, scabrid texture. The leaves are mostly opposite below and alternate above, sessile, oblong to lanceolate, the margins entire and undersurface hispid. The flowers are solitary or in lax leafy cymes, nodding on recurved pedicels; the calyx is deeply lobed and sagittate at the base, and the pale blue to bluish-white corolla is rotate with a short tube and a twisted, beaked cone of connivent anthers projecting from the throat, a hallmark of the genus. The fruit separates into four ovoid, tuberculate nutlets enclosed by the enlarged, persistent calyx.
Trichodesma is distinguished within tribe Boragineae by its protruding, spirally twisted anther cone, and T. indicum is the most widely distributed species, much used in traditional South Asian medicine. Its bristly indumentum and burr-like calyx-enclosed nutlets aid epizoochorous dispersal, while its ruderal ecology has carried it far beyond its native range as an introduced weed. Common and adaptable, it is of no conservation concern.
Author: (L.) Lehm. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Pakistan, Flora of British India, Boraginaceae monograph (Kazmi revision of Trichodesma)