Bidens frondosa L.
beggars' ticks
Erect, glabrous or almost glabrous annual, 20-200 cm tall. Stems angled, branched above to form infl., and sometimes from base. Lvs petiolate, 1-pinnate, with 1-2 pairs of leaflets and a slightly larger terminal leaflet; leaflets sessile or shortly petiolulate, narrow-ovate to lanceolate, coarsely or unevenly serrate, acuminate, (1)-2-13 cm long. Upper cauline lvs becoming smaller, shortly petiolate, and often simple and not lobed or 3-lobed. Capitula 10-20 mm diam. Outer involucral bracts 4-9, foliaceous, usually ciliate at least at base, sometimes glabrous, linear to narrowly oblong-obovate, (10)-15-30 mm long; inner bracts many, membranous, triangular to subulate, 6-10 mm long, with dark lined centre and pale margins. Receptacular scales similar to inner bracts but narrower. Florets usually all ⚥, tubular, yellow-orange, rarely a few orange ray florets present. Achenes flattened, ovate-cuneate with 1 slender rib on each face, dark brown, ciliate, and otherwise glabrous to sparsely hairy, 6-10 mm long; awns 2, 2.5-4.5 mm long.
N.: throughout; S.: Nelson, Marlborough, N. Canterbury, Christchurch.
N. America 1907
Swamps, edges of streams, drains, lakes and ponds, also in waste places and gardens.
FL Nov-May.
B. frondosa is distinguished from the other common sp. in N.Z., B. pilosa, by its larger capitula and ovate-cuneate achenes with only 2 awns (Fig. 21). Early records of B. tripartitus for N.Z. (e.g., Allan 1940) and of B. vulgata are all referable to B. frondosa.
