Flora of New Zealand Series

button Onehunga weed

Prostrate annual, forming patches up to c. 20 cm diam. Stems sparsely to moderately clothed in long hairs. Basal and lower cauline lvs petiolate, sheathing at base, moderately hairy, 2-3-pinnatisect, up to c. 12 × 3 cm; primary divisions in 4-8 pairs; ultimate segments narrow-elliptic to subulate, all in one plane. Cauline lvs similar to basal, but usually smaller. Involucral bracts in 1-2 rows, hairy, obtuse to apiculate, 3-5 mm long. Capitula inconspicuous at flowering, clustered near base of plant and separated by short obscured internodes, 5-12 mm diam. at fruiting, with 30-numerous mature achenes. Achenes 3-4.5 × 1-1.5 mm (including spine), sometimes with short hairs on both surfaces but not on wings, with long erect hairs at apex giving a woolly appearance to the fruiting capitulum; lateral angles entire, with narrow thick wings horizontally ridged in lower ⅔, rounded or squared to apex; spine 1-2 mm long.

N.: established in Northland, recently collected further south at Palmerston North and Lake Wairarapa.

Brazil, Paraguay, Uruguay, Argentina 1883

Mostly waste places, also pastures.

This sp. has been confused in N.Z. with wingless forms of S. sessilis, but is easily distinguished by the large woolly fruiting heads clustered at the base of the plant, and by the thick, narrow wings and horizontal ridges of the achenes. N.Z. material is fairly uniform in achene morphology. S. anthemifolia belongs to subgen. Gymnostyles.