Flora of New Zealand Series

sea aster

Tap-rooted annual or short-lived perennial herb, glabrous or rarely with a few hairs on upper stem; stems erect, terete, sparingly branched below, 20-200 -(300) cm tall, rarely stems resprouting and somewhat woody after flowering. Mid cauline lvs lanceolate to linear, apetiolate and cuneate, acute, crenulate or remotely serrulate, 35-150 × 3-10-(20) mm; lowermost lvs mostly petiolate, elliptic, cuneate, obtuse; uppermost lvs linear. Infl. a many-headed diffuse panicle. Capitula 2-5 mm diam. Involucral bracts very unequal; inner bracts narrow-oblong to subulate, acute to slightly acuminate, green toward apex and along midrib, purplish at apex and margins, 5-8 mm long; outer bracts not wholly herbaceous, c. 2 mm long. Ray florets numerous; ligules white to pale purple, c. 1-2 mm long. Achenes subcylindric to ellipsoid, compressed, 4-5-ribbed, 1.5-2.2 mm long, with sparse antrorse hairs.

N.: throughout, especially coastal areas; S.: Picton and Blenheim (Marlborough); K.

N. and possibly C. and S. America 1896

Swamps, coastal sites, waste places.

FL Jan-Jul-(Dec).

This sp. is well-established in warm coastal areas. N.Z. plants match descriptions of forms of A. subulatus from S. U.S.A., but correspond less well to descriptions of S. subulatus from N. U.S.A. and Canada. Similar plants naturalised in southern Europe and Natal have been treated recently as the C. and S. American A. squamatus (Sprengel) Hieron., but it is unclear how this sp. differs from A. subulatus. N.Z. plants have also been mistakenly identified as A. imbricatus. In the absence of a satisfactory treatment of this group of American spp., N.Z. plants are referred here to A. subulatus sens. lat.

Of the naturalised Aster spp., A. subulatus is the only one likely to be confused with Conyza spp., but spp. of the latter genus are easily distinguished by either the very hairy or much shorter (< 4 mm) involucral bracts.