Zanthoxylum rhetsa (Roxb.) DC.

Candolle, A.P. de (1824) Prodromus systematis naturalis regni vegetabilis 1: 728.

Indian Ivy Rue; Cape Yellowwood

Corky bumps or squat, conical prickles usually present on the trunk. Dead bark layered, mustard yellow when cut. Blaze finely layered, darkens markedly on exposure.

Leaflet blades about 4-9 x 2-3.5 cm, leaflet stalks about 2-3 mm long. Lateral leaflets unequal-sided, particularly towards the base. Oil dots sparsely scattered in the leaflet but always present at the base of each indentation on the margin of the leaflet blade. Midrib depressed on the upper surface. Lateral veins forming definite loops inside the blade margin. Leaf scars on the twigs show three definite bundles of vascular strands.

Inflorescence about 8-14 cm long, shorter than the leaves. Sepals about 0.5-1 mm long. Petals 1-2 mm long. Staminal filaments about 2.5-3 mm long, inserted outside the disk, anthers about 1.5 mm long. Disk irregularly lobed, about 0.5 mm high. Ovary about 1 mm long, style eccentric.

Fruits globose, about 6-7 mm diam., surface marked by numerous oil glands. Seeds +/- globular, about 6 mm diam.

Cotyledons orbicular to oblong, rather thick, about 5-6 x 5 mm, margins crenate or appearing crenate because of the marginal oil dots. At the tenth leaf stage: leaf compound, with about nine leaflets. Leaflet blades with about 3-6 teeth on each side. Each tooth with a large oil dot at the base of the sinus. Compound leaf rhachis grooved on the upper surface and armed with curved red spines about 1.5 mm long. Seed germination time 137 days.

Occurs in WA, NT, CYP and NEQ. Altitudinal range from sea level to 200 m. Grows in monsoon forest and drier, more seasonal rain forest. Also occurs in Asia and Malesia.

The hard black seed are collected by the children as pellets for their bamboo pea-shooters. Corner (1988).

Fagara rhetsa Roxb., Fl. Ind. ed Carey & Wa.ll 1: 438(1820), Type: Lectotype: Roxburgh Icones 185, cult. Bot. Gard. Calcutta. Zanthoxylum parviflorum Benth., Flora Australiensis 1: 363(1863), Type: "N. Australia. Goulburn Island, A. Cunningham; Port Essington, Armstrong; islands of the Gulf of Carpentaria, R. Brown." Lectotype: "Armstrong 569, Australia, Northern Territory.".