1.
Acanthospermum australe
(Loefling) Kuntze, Revis. Gen. Pl. 1: 303. 1891.
Melampodium australe
Loefling, Iter Hispan., 268. 1758;
Acanthospermum xanthioides
(Kunth) de Candolle.
Plants
10—60(—120+) cm.
Stems
± procumbent.
Leaf blades
deltate to ± rhombic or ovate, 13—37 × 7—32 mm, faces sparsely scabrellous to glabrate or glabrescent, gland-dotted.
Fruits
plumply ellipsoid to fusiform, weakly compressed, 7—9+ mm, 5—7-ribbed, lacking terminal spines, prickles ± uncinate, mostly along ribs.
2
n
= 22.
Flowering year round, mostly Jul—Aug. Disturbed, often sandy sites; 0—300 m; introduced; Ala., Ark., D.C., Fla., Ga., La., Mass., Miss., N.C., Oreg., Pa., S.C., Tex., Va.; South America; also introduced in Mexico, West Indies, Central America, Europe, Asia, Africa, Pacific Islands (Hawaii).
Reports of
Acanthospermum xanthioides
(Kunth) de Candolle from New York are evidently based on specimens of
A. australe
.
