Description: Annual or perennial herbs with sessile, tomentose leaves.
Leaves basal and cauline; alternate, sessile; linear to oblanceolate to spathulate, densely woolly hairy to glabresent.
Flower heads disciform, small, inconspicuous, in headlike clusters, or in more or less elongated spikes. Outer florets purple, female, filiform and outnumber the central florets. Central florets purple. Anthers with flat appendages. Style branches truncate with hairs apically. Receptacle flat and with no scales.
Pappus of basally connate (united at base), capillary, barbellate bristles, falling as a unit.
Distribution and occurrence: World: 50 species. Native to North and South America, introduced to many parts of the world. Australia 6 species naturalised. NSW: 4 species naturalised.
Text by Lawrence Mou
Taxon concept: Bremer, K. 1994, Kubitzki, K, 2007,
| | Key to the species | |
| 1 | Leaves densely white woolly on both surfaces (looking grey-green) | 2 |
| Leaves darker than grey-green with fewer hairs (to glabresent) on the upper surface than the lower surface; large leafy annuals with distinct rosettes | 3 |
| 2 | Involucres not purplish, 3–3.5 mm, bases sparsely cobwebby or glabrous; arrays of heads interrupted; involucral bracts in 5–7 rows, outer ovate-triangular, lengths 1/3–1/2 inner, apices acute-acuminate | Gamochaeta calviceps |
| Involucres usually purplish, (at stereome-lamina junctions of involucral bracts), 2.5–3 mm, bases sparsely cobwebby; arrays of heads initially uninterrupted and cylindric; involucral bracts in 3–4(–5) rows, outer ovate-lanceolate, lengths 1/2–2/3 inner, apices narrow to broad acute
Back to 1 | Gamochaeta antillana |
| 3 | Heads surrounded by and almost obscured by, long woolly hairs; leaves loosely woolly on lower surface | Gamochaeta pensylvanica |
| Woolly hairs at the base of the heads limited to the peduncles; leaves with fine, appressed hairs below, or glabrous
Back to 1 | 4 |
| 4 | Leaves with a prominent paler midvein on the upper surface; inflorescences usually a closed spike | Gamochaeta coarctata |
| Leaves concolorous on the upper surface; inflorescences slightly loose and spreading, the heads not held together tightly
Back to 3 | 5 |
| 5 | Flowers with purple tips; basal leaves usually persisting in a rosette at flowering, not clasping or decurrent | Gamochaeta purpurea |
| Flowers with yellowish tips; basal leaves usually withering or withered by flowering and not persisting in a rosette, often clasping to main stem but not auriculate
Back to 4 | Gamochaeta americana |
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