Ruiz & Pav.
Description
Calceolaria tripartita is a Neotropical annual herb native to the Andean region of South and Central America, its GBIF distribution centred on Ecuador, Peru, Bolivia, Colombia, Brazil and adjacent countries, but it has become a widespread weed of warm-temperate uplands and is now naturalised in New Zealand, Australia, Sri Lanka, Indonesia and parts of the Himalaya. It colonises moist, disturbed ground, streamsides, cultivated land, ditches and roadside banks. The photographed plant from above Yoksam in Sikkim at around 2750 m, recorded in August, documents this naturalised Himalayan occurrence, where the monsoon-moistened, disturbed montane habitat closely mirrors its native ecology.
The plant is a slender, erect, glandular-pubescent annual with branched, somewhat succulent stems. The leaves are opposite, the lower often pinnately three-parted (whence tripartita) into toothed segments, the upper smaller. The flowers are borne in lax terminal cymes and display the distinctive Calceolaria form: a strongly two-lipped, yellow, slipper- or pouch-shaped corolla, the small upper lip and the inflated, saccate lower lip enclosing the two stamens. The fruit is an ovoid, septicidal capsule releasing abundant minute, reticulate seeds well suited to wind and water dispersal.
The genus, the slipperworts, is now placed in its own family Calceolariaceae, formerly within the Scrophulariaceae. The pouched corolla is associated with specialised oil-collecting bee pollination in its native Andean range. As an aggressive colonist of disturbed ground, C. tripartita exemplifies a Neotropical weed that has crossed into Old World mountain systems through human agency; it is of no conservation concern and is, rather, regarded locally as an invasive.
Author: Ruiz & Pav. · Sources: POWO (Kew), GBIF, Flora of China Vol. 18, Flora of Nepal, A Revision of the Genus Calceolaria (Calceolariaceae), Flora of Ecuador