Sigesbeckia orientalis L.
Annual herb, 20-100 cm tall. Stems usually moderately to densely hairy, sometimes only sparsely hairy or becoming glabrous below, much-branched often from base and above. Lower and mid cauline lvs moderately to densely clothed in broad-based hairs on upper surface and in simple and sessile glandular hairs on lower surface, usually apetiolate or shortly petiolate but lamina long-cuneate at base, usually triangular or ovate-triangular, sometimes ovate-elliptic, subacute to acute at apex, ± entire to irregularly toothed with larger teeth toward base, 3-10-(17) cm long. Upper cauline lvs becoming smaller, narrow- elliptic or lanceolate, short-cuneate or obtuse at base and less distinctly toothed. Capitula (excluding bracts) 6-10 mm diam., in loose panicles. Outer involucral bracts 5, clothed in conspicuous, mostly stalked, glandular hairs and sometimes simple hairs, linear-spathulate, 5-10 mm long, much > inner bracts. Inner bracts 5-11, with sparse simple hairs and sometimes few to many glandular hairs, obovate, c. 3 mm long, enfolding outer achenes. Receptacular scales similar to inner bracts, usually with simple hairs at apex only. Ray florets 3-5; ligules yellow, 3-fid. Disc florets 4-20, yellow. Achenes glabrous, dark brown-black, curved, irregularly 3-4-angled, 2-3 mm long.
N.: from Bay of Plenty and Lake Taupo area northwards; K.
Warm temperate and tropical Africa to Asia 1855
Forest margins and clearings, coastal sites, riverbeds, pasture.
FL Sep-Jul.
S. orientalis was included by Allan (1961) as doubtfully indigenous except perhaps in K. The sp. is almost certainly a Polynesian introduction to N.Z., including K., and is considered to be introduced through much of the Pacific (see, Sykes 1977). The long, narrow, spreading, glandular, outer involucral bracts distinguish S. orientalis from all other members of the Heliantheae wild in N.Z.
