Siloxerus

Western Australia

Habit, vegetative morphology. Acaulescent (S. pygmaeus) or caulescent, annual, forbs. Leaves basal (only) or basal and cauline, rosulate, opposite (at least basally) or alternate and opposite, simple (sessile). Leaf blades entire, linear (filiform), more or less hairy (tomentose on both surfaces) or glabrous; hairs eglandular; margins entire. Inflorescence. Plants hermaphrodite. Unit inflorescences arranged in synflorescences, synfloresences condensed, heads forming compound heads (dense, globose; general receptacle hairy) or not forming compound heads. General involucre well-developed; bracts leaf-like. Capitula discoid, homogamous, small, somewhat ill-defined; florets 4–15(–22), radially symmetrical florets spread throughout capitulum. Involucral bracts uniseriate to biseriate (5–15), entire, chartaceous (more or less rigid), not fenestrate (stereome undivided), more or less uniform, monochromous, hyaline, transparent. Receptacles conical, paleate, paleas not bristlelike (resembling capitular bracts, one bract per floret). Marginal florets. Marginal florets absent. Disc florets. Inner (central or disc) florets bisexual. Corolla tubular, yellow, 3–5 lobed, lobes erect, lobes with veins ending below apex. Stamens of male fertile florets. Stamens 3–5. Anthers ecalcarate. Tip appendages concave, as wide as the thecae. Base appendages caudate, tails short; endothecial tissue thickening polarized. Styles of female fertile florets. Style branches truncate (with hairs apically). Style branch appendages lacking. Sweeping-hairs obtuse; in a terminal brush. Stigmatic area separated into two ventro-marginal bands along each style branch. Fruit. Achenes homomorphic, more or less obovoid, vascular bundles 2, wall pink or purplish, duplex hairs present (sparse, short, globose), myxogenic; carpopodium absent or indistinct (absent). Pappus present, uniform, jagged and scale-like; apical cells acute; cup laciniate. Testa smooth (with globose hairs without a basal cell).

Etymology. A name at complete variance with the etymology given by its author, namely from the Greek onkeros swollen + stylos, pillar, column; possibly referring to the supposedly swollen bases of the florets of the original species, S. humifusus.

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