Canavalia papuana

wild jack bean


Canavalia papuana

Merr. & L.M.Perry 1942

pronounced: kan-uh-VAY-lee-uh pap-yoo-AH-nuh

(Fabaceae — the hibiscus family)

subfamily: Faboideae - the bean subfamily


common name: wild jack bean

native 4Canavalia is the Latinized form of the Malabar vernacular kanavali, the name for this genus of climbing herbs; papuana is, as you would expect, botanical Latin for ‘from Papua’. As well as in PNG, the plant is also found in northern Australia, from Western Australia across the Northern Territory to Cape York Peninsula and the rest of north-east Queensland, as far south as Rockhampton. Its altitudinal range is from sea level to about 600 m. The type species was described in what was then British New Guinea in 1936 near Lake Daviumbu, Middle Fly River, climbing over low second growths, and this is a typical habitat. The plants photographed on Magnetic Island were on either side of the walking track from Horseshoe Bay to Arcadia, on the flat section at the Horseshoe Bay end, climbing over other vegetation on both sides of the track, up to a height of 4 – 5 m. Unlike its cousin Canavalia rosea, it is not associated with dunes.

This is a slender vine whose stem does not exceed a diameter of 2 mm. The blades of the trefoil leaves are about 5 – 18 by 2.5 – 10 cm, and the leaflet stalks about 5 – 20 mm long. The middle leaflet is larger than the lateral leaflets. The underside of the leaf blades is sparsely clothed in hairs, at least along the midrib. The stipules are hairy, about 1.5 – 4 mm long, recurved. There are usually 5 – 7 lateral veins on each side of the midrib. The stalk of the middle leaflet is longer than those on the lateral leaflets.

The inflorescence is an elongated raceme up to about 40 cm long; the flower colour is variable: blue, purple, pink, cream or white. The flowers are about 2 cm in diameter, borne in pairs on a tubercle-like projection ornamented with a number of nectariferous glands. The calyx tube is about 7 mm long, the upper two lobes rounded, about 2.5 mm long, the lower three lobes narrow, pointed, about 21 mm long; the keel is wider than the wings, but also about 21 mm long. There are 10 stamens, each about 20 mm long; the filaments of 9 of the stamens are fused to form a tube about 17 mm long, open on one side. The free parts of the filaments are about 4 – 6 mm long, alternately longer and shorter. The filament of the tenth stamen is at least partly free. The disk is about 2 – 5 mm high; the ovary hairy, about 1.5 mm long. The stigma is terminal, sticky, and slightly flared. There are 10 – 12 ovules.

The fruit pods are about 15 by 2 by 1 cm, the perianth persistent at the base. There are usually 8 – 12 seeds per pod. Each seed is about 15 by 12 by 8 mm, the testa mottled. The hilum is large, 7 or 8 mm long; the radicle curved, about 3 mm long.


Photographs taken in Horseshoe Bay 2011
Page last updated 27th October 2018