DistributionL. sphaerica is found naturally in tropical and southern Africa from Somalia down to the Western Cape; it also grows on Madagascar and the Comores. In southern Africa it has been recorded from Botswana and the following provinces in South Africa: Limpopo, Mpumalanga, KwaZulu-Natal, Eastern Cape and Western Cape to about Knysna. It should also occur in Swaziland, but apparently has not yet been collected there.
Perennial with a woody rootstock. Stems annual, herbaceous, robust, climbing or trailing, angular, hairless, up to 10 m long or longer, often completely leafless when fruiting. Leaves rather rigid, shaped like a hand, margins toothed, 50-180 mm long, both surfaces roughly and shortly hairy, upper surface dark green, lower surface paler; foetid when crushed. Leaf stalks 20-80 mm long, with two lateral apical yellow-green glands. Tendrils split in two. Flowers fragrant, opening in the evenings, corollas saucer-shaped, velvety white or cream-coloured with green veins, petals rounded, 22-60 mm long; male and female flowers on separate plants (dioecious). Male flowers 2-10 in racemes, anthers prominent, yellow, greatly contorted. Female flowers solitary, stalked. Fruit hanging from a stout 30-100 mm long stalk, subspherical, 60-100 mm across, deep green with pale green or yellowish transverse, slightly raised patches, with a hard shell and whitish flesh, foul smelling when ripe. Seeds whitish to yellowish, oblong-triangular in outline, flattened, 10-15 mm long.
The wild calabash grows in full sun and semi-shade in forest margins, evergreen and deciduous forests, in riverine woodland, on river banks and in dry river beds, also in dry scrub thickets and ground-water forests (Jeffrey 1967). It is also recorded from swamp forests, littoral dunes and maritime scrub on the seashore. It is usually found in well-drained loam, sandy loam and stony, sandy soil.
The wild calabash flowers in all months, but mainly from December to May. Fruiting specimens have been collected almost throughout the year. In southern Africa it grows from about sea level to 915 m, in dry and wet areas with a rainfall of 200-1 200 mm annually. The flowers are visited by bees, ants and flies and presumably also by moths, as the flowers open in the evenings.
Uses and cultural aspects
According to Watt & Breyer-Brandwijk (1962), the fruit is bitter because of elaterase activity. Hutchings et al. (1996) report that in Zulu medicinal usage, infusions made from two handfuls of a mixture of leaves or roots with those of Bidens pilosa (blackjack), in a large cupful of hot water, are taken for stomach ache or administered as enemas. Pounded root decoctions are used for treating swellings thought to be caused by blood disorders. The fruit is also used as traditional medicine, sometimes in succession ceremonies after the death of a chief. The fruit is reported to be an ingredient in a Xhosa remedy for glandular swellings. Walker (1996) notes that the fruit is sold on Indian markets 'as they are used for Hindu prayers'.