Franch
Description
Parnassia delavayi is an alpine perennial herb of the eastern Himalaya and southwestern China, recorded by GBIF from China, Bhutan and India across roughly 1128 occurrences. It is a plant of cold, moist alpine habitats, growing in wet meadows, marshy turf, streamsides, seepage zones and damp grassy slopes within the alpine belt. The photographed individual was found in Bhutan along the Ludlow-Sherriff Trail near Dem-Tso at 4650 m in June, a high glacial-lake margin that exemplifies the species' affinity for saturated, peaty alpine ground.
It forms tufted perennials arising from a short rhizome, with basal leaves that are long-petiolate and cordate-ovate to reniform with an entire margin. The flowering stem is erect and bears a single, sessile or clasping cauline leaf below the solitary terminal flower. Each flower has five free, white petals, often delicately veined, alternating with five green sepals. Characteristic of the grass-of-Parnassus group are the conspicuous fimbriate staminodes positioned opposite the petals and dissected into gland-tipped filaments, which alternate with five fertile stamens surrounding a superior ovary; the fruit is a loculicidal capsule containing many small winged seeds.
GBIF accepts the name. Though long placed in Saxifragaceae or its own family Parnassiaceae, Parnassia is now embedded within Celastraceae on molecular grounds, the family label given here reflecting that modern circumscription. The elaborate fringed staminodes function as nectar-mimicking attractants for fly and small-bee pollinators. With a wide montane range in remote alpine terrain, P. delavayi faces no significant conservation threat.
Author: Franch · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, monograph of Parnassia