Flora of New Zealand Series

American fireweed

Erect annual herb, up to c. 2 m tall. Stems sparsely hairy to glabrous, branched above. Lvs glabrous or sparsely hairy on veins below, apetiolate, lanceolate, oblanceolate or narrow-elliptic, cuneate and sometimes amplexicaul, or broad at base, irregularly serrate or with triangular lobes and again serrate, 6-20 × 1-8 cm; uppermost lvs smaller, often lanceolate or linear. Capitula in dense or open panicles. Supplementary bracts 5-14, linear, 3-5 mm long. Involucral bracts 12-15, linear, (8)-11-13 mm long. Disc pale yellow, 5-8 mm diam. Achenes subcylindric, narrowed to apex, 2.5-3.5 mm long, sparsely hairy between ribs; pappus white, 12-15 mm long.

N.: Whangamarino, Rotorua and scattered localities in Bay of Plenty.

Eastern N., C., and S. America 1957

Forest margins, waste places, wet sites.

FL Jan-Apr.

American fireweed is distinguished from all N.Z. erechtitoid senecios by the large, very long capitula. It is known in N.Z. from only a few collections and nowhere appears to be well established. All N.Z. collections are referable to the type var. of this variable sp.