Australian Waterbuttons

Annuals, 2–10(–25+) cm. Stems branched ± throughout, ± strigillose to villous, glabrescent. Leaves petiolate or sessile; blades obovate to spatulate, 2–3-pinnately lobed (ultimate lobes narrowly spatulate to linear), (1–)2–3(–6) cm. Involucres 3–4(–6) mm diam. Phyllaries 13–22+ in 2–3 series, subequal (apices brown). Ray florets 0 (peripheral pistillate florets 8–80+ in 1–3+ series; corollas 0). Disc corollas ochroleucous to pale yellow, 0.5–0.8 mm. Cypselae: outer stalked, 1–1.2 mm, ± winged, faces ± papillate; inner sessile, 0.8–1 mm, not winged, not papillate. 2n = 36, 40.

Anacyclus australis Sieber ex Sprengel, Syst. Veg. 3: 497. 1826

australis: southern

Annual, prostrate or ascending, herb, to 25 cm. Leaves 2-pinnatifid, oblanceolate in outline, thinly pubescent; base semi-amplexicaul. Capitula solitary, terminal, ± flattened, borne on a long peduncle, 1.5-7.5 cm long, much longer than in C. anthemoides. Phyllaries elliptic, with scarious margins, borne in 2 rows. Outer florets lacking a corolla; inner florets white or yellow-green; all florets stalked. Achenes dimorphic; those of outer florets elliptic, winged; those of inner florets obovoid, not winged.

Occasional

Native of New Zealand and Australia; now widespread as a weed in the warmer parts of the Old and New Worlds

Lancisia australis (Sieber) Rydberg
Anacyclus australis Sieber; Spreng. Syst. 3: 497. 1826. Strongylosperma australe Less. Svn. Comp. 261. 1832. Colula australis Hook. f. Fl. Nov. Zeland. 1: 128. 1852.
A low annual ; stem diffuse and much branched, rarely more than 1 dm. high ; leaves 1-2 cm. long, once or twice pinnatifid with lanceolate or linear di-isions, more or less hirsute; heads solitarj' at the ends of the branches; peduncles 2-5 cm. long; involucre rotate, 5-6 mm. broad; bracts oblong, in 2 series, rounded at the apex, with white scarious margins; marginal flowers with slightly winged pedicels, in 2 or 3 series; disk-flowers short-pedicelled ; corollas cylindric, glandular-granuliferous, 1.5 mm. long; lobes 4, rounded-ovate; marginal achenes with broad wing-margins, broadly oval, truncate at the base, emarginate at the apex, glandular-hispidulous on the faces, 1.5 mm. long; disk-achenes oblong, merely margined.
Type locality: Australia.
Distribution: California to Utah and British Columbia; Maine; adventive from Australia and New Zealand.

Cotula australis is a species of plant in the daisy family known by the common names bachelor's buttons, annual buttonweed, southern waterbuttons and Australian waterbuttons. This small plant is native to Australia and New Zealand, but it is known in other areas of the world as a common weed (South America, California, Mexico, South Africa, etc.).

Cotula australis grows low to the ground in a thin mat with some slightly erect, spindly stems. The leaves are divided and subdivided into fringelike lobes. The plant flowers in inflorescences only a few millimetres wide containing minuscule yellow disc florets surrounded by greenish brown bracts and rudimentary ray florets that have been reduced to pistils with no stamens or corolla. The fruit is a tiny winged achene about a millimetre wide.