Coccinia Wight & Arn. is a genus of approximately 25 species of perennial climbing or creeping herbs in the family Cucurbitaceae (order Cucurbitales), distributed primarily across sub-Saharan Africa, with one species extending into tropical Asia and beyond.
Plants climb by means of simple or unequally bifid tendrils. Most species develop a tuber from the hypocotyl, occasionally also on roots. The leaves are usually stalked and range from simple to deeply lobed, typically with toothed margins; the lower leaf surface often bears small nectar-producing glands. Coccinia species are dioecious — individual plants bear either male or female flowers, never both. The corolla is five-lobed and ranges in colour from creamy white to yellowish orange. Male flowers occur singly, in fascicles, or in racemes and bear three stamens fused into a single filament column; female flowers are usually solitary and possess an inferior ovary of three carpels. The fruit is a distinctive berry with red flesh and red skin, occasionally showing white longitudinal mottling. Seeds are flat to lentil-shaped and enclosed in a juicy aril.
The most economically significant member is C. grandis (ivy gourd or scarlet gourd), cultivated across South and Southeast Asia as a leaf vegetable and functional food, and also used in traditional medicine. C. grandis has become naturalised across tropical regions and is considered an invasive weed in Hawaii. The remaining ~24 species are native to sub-Saharan Africa, inhabiting environments from semi-arid savannas and lowland forests to montane forests, with adaptations to these contrasting habitats having arisen independently multiple times across the genus.
The genus name derives from the Greek kokkinia ("red" or "scarlet"), an allusion to the conspicuous red fruit that gives the plants their common name, the scarlet gourds.
Etymology
The genus name Coccinia is derived from the Greek kokkinia (also kokkinias), meaning "red" or "scarlet", a direct reference to the brightly coloured red fruit characteristic of the genus.
Distribution
All species in the genus are native to sub-Saharan Africa, occurring across a range of habitats from semi-arid savannas to rain forests and, less commonly, montane forests. One species, C. grandis, also has a native range extending into tropical Asia and has been widely introduced to Australia, several Pacific Islands, and the tropical Americas, where it occasionally establishes as an invasive weed.
Ecology
Coccinia species have colonised a broad spectrum of African habitats, from semi-arid savannas to moist lowland and mountain forests. Phylogenetic evidence indicates that transitions between these contrasting habitat types have occurred independently multiple times within the genus. The small nectar-producing glands on leaf undersides suggest extrafloral nectary function. C. grandis demonstrates strong invasive capacity outside its native range, particularly in Hawaii.
Cultural Uses
Coccinia grandis is cultivated across South and Southeast Asia as a leafy vegetable and functional food. Various parts of the plant are used in traditional medicine across its range. Outside cultivation, the species has become naturalised in tropical regions globally.
