Description: Annual and perennial herbs or subshrubs, with a woody taproot.
Leaves mainly cauline and reducing in size up stem; alternate, margins entire; basal leaves withering early.
Infloresence an ovoid, cylindrical or globose compound head of 40–200 sessile partial heads on a general globose or elongate receptacle; common involucre of mainly herbaceous bracts usually similar to uppermost leaves, or absent; partial heads each with 3–8 bisexual florets and subtended by a main bract of the partial involucre, central region (stereome) with or without scarious margins or tip; partial heads comprising a few scarious involucral bracts surrounding the florets and the florets arranged along a much-reduced spike, each floret subtended by a scarious bract (scale), no specialized common receptacle present, all scarious bracts and scales tinged yellow or golden; Corollas tubular, 5-merous, lobes yellow. Anthers finely tailed at base and with triangular appendages at the apex. Style branches flattened, linear-oblong, truncate, papillose with fimbriate apices.
Achenes obovoid, silky, the hairs biseriate, obtuse; pappus a single ring of plumose bristles, fused for various lengths at the base, yellow at least at tip with stiff spreading plumose branches.
Distribution and occurrence: World: 6 species, endemic Australia. Australia: Qld, N.S.W., Vic., S.A.
Text by A. N. L. Doust & J. Everett
Taxon concept:
| | Key to the species | |
| 1 | Main bract of the partial involucre with scarious margins at least as broad as stereome and extending well beyond stereome tip, stereome usually narrow | 2 |
| Main bract of the partial involucre without scarious margins or occasionally with narrow scarious margins less than half as broad as stereome, with or without a scarious tip, stereome usually broad | 3 |
| 2 | Compound head often branched at the base or from within the head; main bract of the partial involucre broad-ovate with a narrow-linear glandular stereome, and broad spreading scarious margins; leaves with few or no fine woolly hairs | Pycnosorus pleiocephalus |
| Compound head never branched; main bract of the partial involucre linear-ovate with a narrow-clavate stereome, margins not broadly spreading; leaves densely covered in fine woolly hairs
Back to 1 | Pycnosorus thompsonianus |
| 3 | Main bract of the partial involucre comprising a tough brown glandular stereome, rarely with narrow membranous margins at base, without woolly hairs; leaves 1-ribbed, discolorous, upper surface dark grey-green, always darker than the stems, lower surface similar or grey | Pycnosorus chrysanthes |
| Main bract of the partial involucre with a narrow membranous tip about half as broad as the stereome, and with narrow membranous margins towards the base; leaves usually 3–8-ribbed (rarely only 1-ribbed), concolorous with long fine appressed hairs
Back to 1 | Pycnosorus globosus |
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