Greek ozo — to smell, thamnos — shrub, as many of the species are fragrant.
Shrubs, often fragrant, glabrous to hairy. Stems prostrate to erect. Leaves along stems, alternate, margins mostly entire, usually sessile. Capitula diskiform or diskoid, terminal or axillary, in corymbs or panicles, with or without stalks. Involucral bracts in several rows, overlapping, unequal, with or without coloured radiating laminas. Receptacle flat. Outer florets female, filiform, yellow, often absent. Inner florets bisexual, tubular, yellow or white. Achenes cylindrical or 4-angled, with twin warty protuberances, sparsely hairy. Pappus of free barbed bristles.
Small-leaved species sometimes available are: O. coralloides Hook. f. from New Zealand, a small spreading shrub with appressed oblong leaves and solitary diskiform capitula to 8 mm across surrounded by leaves [Helichrysum coralloides Benth.]; O. hookeri Sond., Kerosene Bush, from SE Australia, a large erect shrub with appressed, linear to oblong leaves and diskoid capitula to 2 mm across in dense terminal clusters [Helichrysum hookeri (Sond.) Druce]; O. scutellifolius Hook. f. from Tasmania, a large erect shrub with appressed, almost circular, reflexed leaves and diskiform capitula to 4 mm across in small terminal clusters [Helichrysum scutellifolium (Hook. f.) Benth.]; and O. selago Hook. f. from New Zealand, a small spreading shrub with appressed, ovate to triangular, keeled leaves and solitary diskiform capitula to 6 mm across. [Helichrysum selago Benth.]
O. obcordatus DC. from E Australia is a large erect shrub with short broad leaves, diskiform capitula to 2 mm across in dense terminal clusters, and straw-coloured involucral bracts. [Helichrysum obcordatum (DC.) Benth.]
Mostly aromatic shrubs; involucral bracts often coloured, with spreading tips.
About 50 species from Australia, New Zealand and New Caledonia.
Source: (2002). Dahlia. In: . Horticultural Flora of South-eastern Australia. Volume 4. Flowering plants. Dicotyledons. Part 3. The identification of garden and cultivated plants. University of New South Wales Press.