D. Don
Description
Mazus surculosus D.Don is a small, creeping perennial herb of moist temperate habitats in the Himalaya and adjacent mountains. GBIF records it from India, Nepal, China, Bhutan and Pakistan, with some 230 occurrences, indicating a Sino-Himalayan distribution. It grows on damp, shaded ground — streamsides, wet banks, mossy turf and the margins of paths and forest clearings — typically between about 2,000 and 3,200 m. The illustrated material is from central Nepal at Bagong-Khola, 2,650 m, and from East Nepal at Gupka Pokhari, 2,920 m, both flowering in April, in keeping with its early-spring phenology.
The plant is mat-forming, spreading by slender, rooting stolons or surculose runners (whence surculosus), from which arise short ascending flowering shoots. The leaves are mostly in a basal rosette, obovate to spathulate, crenate-toothed, narrowed to a winged petiole, with a few smaller opposite leaves on the stem. The flowers are borne in lax, few-flowered racemes; the corolla is strongly bilabiate, blue-violet to purple, the short upper lip two-lobed and the larger lower lip three-lobed and marked with white and yellow palatal ridges spotted with darker colour. The fruit is a small, rounded, loculicidal capsule enclosed by the persistent calyx, releasing numerous minute seeds.
Mazus, formerly placed in Scrophulariaceae, is now referred to Phrymaceae (or the segregate Mazaceae) on molecular grounds, and the input family Phrymaceae reflects this modern placement. The genus is centred in temperate and subtropical Asia. As a widespread, weedy creeper of damp open ground, M. surculosus is common and not of conservation concern.
Author: D. Don · Sources: POWO (Kew), GBIF, Flora of China Vol. 18, Flora of Bhutan Vol. 2, Flora of Nepal, Beardsley & Olmstead: Redefining Phrymaceae (American Journal of Botany)