Xanthium spinosum
L. Bathurst BurrErect, much-branched herb to c. 1 m high; stems pubescent, armed at leaf-bases with 1 or 2, rigid, yellowish 3-fid spines 7–25 mm long. Leaves narrow-rhombic to lanceolate in outline, mostly 3–8 cm long, 8–25 mm wide, simple or 3-lobed, dark green and sparsely pubescent above, silver-felted beneath, apex acute, cuneate at base, margins entire; petiole to c. 1 cm long. Male capitula 2–8, 6–8 mm diam.; involucral bracts ovate to obovate, 1–2 mm long; florets c. as long as involucre, rusty-pubescent. Female capitula usually solitary in axils below males; fruiting involucre ellipsoid to ovoid, 4–5 mm diam., 8–15 mm long, hooked spines 2–3 mm long, pubescent, brown; beaks broad-based, 1–2 mm long, straight. Cypselas c. 1 cm long. Flowers mainly summer.
LoM, MuM, Wim, GleP, VVP, VRiv, MSB, RobP, MuF, GipP, OtP, WaP, Gold, CVU, DunT, NIS, EGL, EGU, HSF, HNF, MonT, VAlp. Also naturalised WA, NT, SA, Qld, NSW, ACT, Tas., New Zealand. Native to South America but widely naturalized. Widespread in Victoria, mainly in the west and north, often in agricultural land, pastures and roadsides and particularly prolific after flooding or high summer rainfall. Declared a noxious weed in all States. .
Jeanes, J.A. (1999). Asteraceae. In: Walsh, N.G.; Entwisle, T.J., Flora of Victoria Vol. 4, Cornaceae to Asteraceae, pp. 652–666. Inkata Press, Melbourne.
Spinning
