Edgew. & Hook. f.
Description
Oxalis griffithii is a woodland herb widely distributed across temperate eastern and southern Asia, ranging from the Himalaya (India, Nepal, Bhutan) through China, Taiwan, Japan, Korea, Myanmar and into Russia, with numerous cultivated and naturalised European records; GBIF logs 6798 occurrences across this broad area. It is a plant of shaded, humus-rich habitats, growing on the floor of temperate broad-leaved and conifer forests, on mossy banks and beside streams, chiefly between about 1500 and 3500 m. The photographed plant from Tongsa (Trongsa) in central Bhutan at 3300 m in April shows it flowering in early spring beneath the still-leafless forest canopy, when light reaches the understorey.
It is a small, delicate perennial herb arising from a slender, scaly, creeping rhizome or bulbil-bearing rootstock. The long-petiolate leaves are basal and trifoliolate, the leaflets obtriangular (broadly obcordate) and notched at the apex, folding downward at night and in dull weather (nyctinasty). The flowers are solitary on slender axillary scapes, with five sepals and five white petals usually marked with fine yellow or pinkish-purple veins at the base. The fruit is an elongate, cylindrical, five-angled loculicidal capsule that dehisces explosively, ejecting the small seeds whose fleshy aril everts to fling them from the parent plant.
The species belongs to Oxalis (Oxalidaceae), the largest genus of its family and the only one of the wood-sorrels well represented in temperate Asia. Its tissues are rich in oxalic acid and soluble oxalates, giving the characteristic sour taste. The explosive ballistic seed dispersal, nyctinastic leaf movements and capacity for vegetative spread by rhizomes and bulbils underlie its wide distribution and ready naturalisation. Common and ecologically adaptable, it is of least conservation concern.
Author: Edgew. & Hook. f. · Sources: POWO (Kew), GBIF, Flora of China Vol. 11, Flora of Bhutan Vol. 1, Flora of Nepal, Monograph of the Oxalidaceae (Knuth, Das Pflanzenreich)