Clausena is a genus of shrubs and trees in the citrus family Rutaceae, placed in the subfamily Aurantioideae — the same subfamily as the genus Citrus. Within that subfamily it belongs to the subtribe Clauseninae, collectively known as the remote citroid fruit trees. The genus was first formally described by the Dutch botanist Nicolaas Laurens Burman in 1768.
Members of the genus range from small shrubs under one metre tall to trees reaching 20 metres, and several species show considerable variation in habit. The leaves are pinnate, divided into distinct leaflets. Flowers are borne in clusters and typically have four or five petals and sepals. The fruit is a berry, but unlike many other Rutaceae it lacks the pulp-filled segments typical of citrus. A key diagnostic feature of the genus is the gynophore, a stalk-like structure that supports the ovary within the flower; its form varies considerably between species, which can make identification difficult.
The genus is distributed across Africa, southern Asia, Australia, and the Pacific Islands. It encompasses roughly two dozen species, among which several are economically or medicinally significant. Clausena lansium, known as wampi, is cultivated as a fruit tree in southern China and Southeast Asia; sour, sweet, and intermediate fruiting varieties exist, and the tree can be grafted onto various citrus rootstocks. Clausena anisata is used across its African and Asian range for its timber and in traditional medicine. Clausena excavata is employed in Asian folk medicine for a range of conditions including snakebite, malaria, dysentery, and HIV infection, and has attracted interest from pharmacological researchers.
Etymology
The genus name Clausena honours Peder Claussøn Friis (1545–1614), a Norwegian clergyman and scholar best known as the translator of the medieval Icelandic historian and poet Snorri Sturluson. The name was assigned by the Dutch botanist Nicolaas Laurens Burman when he defined the genus in 1768.
Distribution
Clausena is distributed across tropical and subtropical Africa, southern Asia (including the Indian subcontinent and Southeast Asia), Australia, and the Pacific Islands. Within Asia, the genus reaches its greatest diversity; Clausena lansium is particularly associated with southern China and Southeast Asia, where it has long been cultivated.
Cultural Uses
Several species have established economic and cultural roles. Clausena lansium (wampi) is cultivated as a fruit tree in southern China and Southeast Asia, valued for its small, grape-like edible berries and available in sour, sweet, and intermediate varieties; it can also be grafted onto citrus rootstocks. Clausena anisata is harvested for timber and is widely used in traditional medicine across Africa and Asia. Clausena excavata is employed in Asian folk medicine to treat snakebite, malaria, dysentery, and HIV infection.
