Zanthoxylum ovalifolium Wight

Rutaceae

Wight, R. (1839) Illustrations of Indian Botany 1 : 169. Type: India, Madras, Wight 356.

Thorny Yellowwood; Oval-leaf Yellow Wood; Little Yellowwood

Seldom exceeding 30 cm dbh. Squat, conical prickles often present on the trunk.

Oil dots quite large, numerous and conspicuous. Both simple and compound leaves usually present on each twig. Leaf or leaflet blades about 6-16.5 x 2.5-7 cm. Lateral veins forming loops inside the blade margin and midrib generally raised on the upper surface of the leaflet blade.

Inflorescence about 3-12 cm long, approximating but usually not exceeding the leaves. Sepals about 1 mm long. Petals about 2.5 mm long. Anther filaments about 2 mm long, inserted outside the sometimes inconspicuous disk, anthers about 0.75 mm long. Disk about 0.5-0.75 mm high. Carpels about 1.5 mm long, style eccentric.

Fruits subglobose, about 6-7 mm diam. Seeds globular, about 4.5-5 mm diam., cotyledons thick and fleshy, marked with large conspicuous oil glands.

Cotyledons elliptic or obovate, about 4-7 mm long, fleshy, without venation. Oil dots large. First pair of leaves with toothed leaflets. Petiole winged. At the tenth leaf stage: leaflet blades elliptic to obovate, apex acuminate, base cuneate often unequal-sided, upper surface glabrous, sometimes with 1 or 2 straight spines on the midrib; oil dots large, easily visible with a lens; petiole usually with one to several spines on the upper surface. Spines also present on the stem and on the flattened upper surface of the compound leaf rhachis. Seed germination time 36 to 47 days.

Occurs in NEQ. Altitudinal range from 400-1100 m. Grows as an understory tree in drier, more seasonal rain forest. Also occurs in Asia and Malesia.

Food plant for the larval stages of the Ambrose Butterfly. Common & Waterhouse (1981).

Zanthoxylum inerme C.T.White & W.D.Francis, Queensland Department of Agriculture and Stock. Botany Bulletin 22: 6(1920), Type: Near Atherton, C.T. White (type); [given by T.G.Hartley, J. Arnold Arbor. 47 (1966) 207 as White, January, 1918, A Zanthoxylum dominianum Merr. & L.M.Perry, Journal of the Arnold Arboretum 22: 32(1941), Type: Based on Fagara varians Domin. Zanthoxylum suberosum C.T.White, Proceedings of the Royal Society of Queensland 53: 208(1942), Type: Based on Zanthoxylum inerme. Fagara varians Domin, Biblioth. Bot. 22: 846(1927), Type: Queensland, Lake Eacham, Feb. 1910, Domin 5657; holo: PR.