Leaves opposite or rarely appearing whorled, palmately 3-foliolate or rarely 1-foliolate; leaflets with margins entire or glandular-toothed; lateral leaflets usually similar to terminal leaflet but smaller.
Inflorescences axillary, cymose. Flowers bisexual, 4-merous. Calyx basally fused, 4-lobed. Petals 4, valvate or imbricate, free, not persistent in fruit. Stamens 4, free, opposite the sepals, erect, incurved. Disc with 4 distinct and prominent gland-like lobes alternating with the petals. Carpels 4, basally fused, lacking a sterile apex; styles fused, arising terminally from the carpels; stigma capitate; ovules 2 in each carpel.
Fruit of 1–4 cocci; cocci not transversely ridged, with rounded apices; seeds released forcibly from dehiscing cocci, dull, black.
A number of species are cultivated as ornamental. This genus is currently under revision.; many of the taxa have manuscript names (ms. after the name) which as yet have not been formally published.
| | Key to the species | |
| 1 | Plants with branchlets prominently ridged due to the presence of ± glabrous leaf decurrencies | 2 |
| Plants with branchlets not prominently ridged | 3 |
| 2 | Branchlets with an indumentum of stellate hairs | 4 |
| Branchlets with an indumentum of simple hairs
Back to 1 | 7 |
| 3 | Branchlets with an indumentum predominantly of simple hairs | 10 |
| Branchlets with an indumentum of stellate hairs
Back to 1 | 17 |
| 4 | Lower surface of leaflets velvety with very short stellate hairs | 5 |
| Lower surface of leaflets not velvety, generally glabrous to hirsute
Back to 2 | 6 |
| 5 | Inflorescences generally shorter than the leaves; calyx lobes usually much shorter than petals; staminal filaments hirsute with simple to stellate hairs, particularly towards the apex, swollen and slightly warty towards apex | Zieria laevigata |
| Inflorescences generally longer than the leaves; calyx lobes almost equal in length to the petals; staminal filaments glabrous, not noticeably swollen or warty towards the apex
Back to 4 | Zieria laxiflora |
| 6 | Lower surface of leaflets glabrous and dotted with pellucid oil glands; staminal filaments not prominently dilated towards the base and not warty towards the apex. | Zieria prostrata |
| Lower surface of leaflets hirsute and lacking pellucid oil glands; staminal filaments dilated towards the base and warty at the apex
Back to 4 | Zieria arborescens |
| 7 | Leaflets ± obovate, 3–6 mm wide, apex rounded to obcordate; upper surface of leaflets glabrous; leaflet margins not recurved | Zieria robusta |
| Leaflets mostly linear to lanceolate or narrow-elliptic, or rarely obovate, 1–3 mm wide, apex mostly acute or sometimes obtuse or rounded; upper surface of leaflets hirsute to ± glabrous; margins usually revolute
Back to 2 | 8 |
| 8 | Leaves with terminal leaflets 9–19 mm long | Zieria ingramii |
| Leaves with terminal leaflets 5–8 mm long
Back to 7 | 9 |
| 9 | Leaves sessile, or nearly so; leaflet margins revolute to the midvein | Zieria aspalathoides |
| Leaves with petioles at least 1 mm long; leaflet margins not revolute
Back to 8 | Zieria odorifera |
| 10 | Plants strongly lemon-scented, procumbent, proliferating from rhizomes; branchlets often with tufts of longer hairs at nodes; restricted to Cooma district (ST) | Zieria citriodora |
| Plants sometimes odoriferous but not lemon-scented; not obviously proliferating from rhizomes; branchlets without tufts of hairs at nodes; widespread but not in ST
Back to 3 | 11 |
| 11 | Central leaflets >10 mm long, 2–8 mm wide; branchlets and flower parts lacking raised oil glands; leaflets ± flat or slightly recurved, margins entire | Zieria pilosa |
| Central leaflets <10 mm long, 1–3 mm wide; upper surface of leaflets, calyx lobes and ovary mostly warted with raised oil glands; margins of leaflets recurved to revolute, mostly appearing finely toothed or crenate due to the raised glands
Back to 10 | 12 |
| 12 | Petals pale to deep pink; inflorescences mostly 3–7-flowered, mostly exceeding the leaves; central leaflets linear to narrow-lanceolate, margins revolute, apex acute | Zieria aspalathoides |
| Petals white or rarely white with the tips pink; inflorescences mostly 1–3-flowered, shorter than or longer than the leaves; central leaflets mostly oblanceolate to obovate or elliptic, margins recurved to revolute, apex mostly obtuse to rounded or obcordate
Back to 11 | 13 |
| 13 | Cocci pubescent or hirsute | 14 |
| Cocci ± glabrous or with hairs only on the margins
Back to 12 | 16 |
| 14 | Petals mostly 4–4.5 mm long; inflorescences mostly longer than the leaves, mostly 3-flowered (range 1–7); northern species, west of Armidale (NT, NWS) | Zieria odorifera |
| Petals usually 2–3.5 mm long; inflorescences shorter than the leaves, 1-flowered or 1–3-flowered; central species and northern species east of Armidale (NT, CT, CWS)
Back to 13 | 15 |
| 15 | Central leaflets cuneate, obcordate or ± obovate, 1.3–3.7 mm wide, 3–8.5 mm long; petiole 1.5–3 mm long; inflorescences 1–3-flowered; near Wellington and Bathurst (CT, CWS) | Zieria obcordata |
| Central leaflets narrow-elliptic to oblanceolate, 1–2 mm wide, 3–6.5 mm long; petiole 0.5–1.5 mm long; inflorescences 1-flowered; near Cathedral Rock N.P. (NT)
Back to 14 | Zieria odorifera |
| 16 | Divaricate shrub to 1 m high; central leaflets cuneate to obovate, 2.5–4 mm long; confined to the Araluen district (SC) | Zieria adenophora |
| Prostrate subshrub to 0.1 m high; central leaflet oblanceolate 4–7 mm long; restricted to gorges SE of Armidale (NT)
Back to 13 | Zieria odorifera |
| 17 | Plants with prominent warts on stems | 18 |
| Plants without prominent warts on stems, although pellucid oil glands may be present
Back to 3 | 27 |
| 18 | Lower surface of leaflets velvety with short stellate hairs | 19 |
| Lower surface of leaflets glabrous to hirsute, but never velvety
Back to 17 | 26 |
| 19 | Upper surface of leaflets ± glabrous | 20 |
| Upper surface of leaflets pubescent to velvety with very short stellate hairs
Back to 18 | 22 |
| 20 | Upper surface of leaflets not warted but dotted with pellucid oil glands; margins not toothed, slightly recurved to revolute but not to the midvein | Zieria hindii |
| Upper surface of leaflets warted; margins ± toothed due to the warts
Back to 19 | 21 |
| 21 | Branchlets hirsute; lower surface of leaflets and calyx lobes with prominent warts; leaflet margins revolute to the midvein; staminal filaments hirsute with stellate hairs | Zieria granulata |
| Branchlets velvety; lower surface of leaflets and calyx lobes not warted; leaflet margins flat, not revolute to the midvein; staminal filaments glabrous
Back to 20 | Zieria adenodonta |
| 22 | Leaflets with upper surface pubescent but not velvety | 23 |
| Leaflets with upper surface velvety
Back to 19 | 24 |
| 23 | Fruit prominently warted; calyx lobes triangular with apex attenuate, lobes much shorter than petals | Zieria parrisiae |
| Fruit not warted but dotted with pellucid oil glands; calyx lobes narrow-triangular, nearly as long as petals
Back to 22 | Zieria tuberculata |
| 24 | Upper surface of leaflets and fruit not warted; inflorescences shorter than leaves | Zieria furfuracea |
| Upper surface of leaflets and fruit warted; inflorescences longer than leaves
Back to 22 | 25 |
| 25 | Anthers with a small terminal appendage; leaflets 3–5 mm wide | Zieria formosa |
| Anthers without an appendage; leaflets 2–3 mm wide
Back to 24 | Zieria buxijugum |
| 26 | Leaflets usually 2.5–3.5 mm wide; petioles 4–6 mm long | Zieria floydii |
| Leaflets mostly 4–7 mm wide; petioles 8–20 mm long
Back to 18 | Zieria smithii |
| 27 | Lower surface of leaflets pubescent to velvety with very short stellate hairs | 28 |
| Lower surface of leaflets glabrous to slightly hirsute
Back to 17 | 37 |
| 28 | Apex of leaflets retuse to emarginate | 29 |
| Apex of leaflets acute to rounded
Back to 27 | 30 |
| 29 | Leaflet margins revolute and secondary venation prominent; inflorescences longer than the leaves; peduncle and calyx lobes pubescent | Zieria baeuerlenii |
| Leaflet margins not revolute and venation obscure; inflorescences shorter than the leaves; peduncle and calyx lobes glabrous/glabrescent
Back to 28 | Zieria minutiflora |
| 30 | Primary bracts persistent on peduncles, leaf-like and ≥7 mm long | 31 |
| Primary bracts caducous, leaving scars on peduncles, or if persistent <1 mm long
Back to 28 | 33 |
| 31 | Leaves dimorphic, generally 1-foliolate and 3-foliolate leaves equally distributed on the branches, more rarely with 1-foliolate leaves only; venation obscure; staminal filaments and ovary glabrous | Zieria involucrata |
| Leaves consistently 3-foliolate; secondary venation obvious; staminal filaments and ovary hirsute or glabrous
Back to 30 | 32 |
| 32 | Leaflets 15–40 mm long, margins ± flat; petiole 3–10 mm long; widespread species | Zieria cytisoides |
| Leaflets 8–11 mm long, margins recurved to revolute; petiole 1–3.5 mm long; coastal species south from Tathra
Back to 31 | Zieria littoralis |
| 33 | Upper surface of leaflets glabrous or glabrescent | 34 |
| Upper surface of leaflets hirsute to densely pubescent
Back to 30 | 35 |
| 34 | Terminal leaflets usually 5–9 cm long; petioles 1.5–3 cm long.; widespread in wet sclerophyll forest and on margins of rainforest on the coast and adjacent ranges | Zieria arborescens |
| Terminal leaflets usually 1–3.5 cm long; petioles <1 cm long; widespread in dry sclerophyll forest, often on rocky ridges or outcrops, coast to inland districts
Back to 33 | Zieria fraseri |
| 35 | Upper surface pubescent with predominantly simple hairs; inflorescences few-flowered, generally <10; filaments not warty at the apex | Zieria murphyi |
| Upper surface of leaves with stellate hairs; inflorescences usually many-flowered, generally >10; filaments warty at the apex
Back to 33 | 36 |
| 36 | Secondary venation obscure on lower surface of leaflets; inflorescences generally longer than the leaves; petals glabrous or glabrescent on the upper surface | Zieria covenyi |
| Secondary venation prominent on lower surface of leaflets; inflorescences generally shorter than the leaves; petals stellate-pubescent on both surfaces
Back to 35 | Zieria arborescens |
| 37 | Lower surface of leaflets glabrous | 38 |
| Lower surface of leaflets hirsute
Back to 27 | 40 |
| 38 | Peduncles hirsute with short stellate hairs; calyx lobes tomentose with short stellate hairs | Zieria southwellii |
| Peduncles hirsute to tomentose with a mixed indumentum primarily of long simple hairs; calyx lobes hirsute with predominantly long simple hairs
Back to 37 | 39 |
| 39 | Primary bracts large and boat-shaped, >7 mm long and >5 mm wide; calyx lobes with very attenuated apex | Zieria caducibracteata |
| Primary bracts small and scale-like, <2.5 mm long and c. 0.5 mm wide; calyx lobes acute, not attenuated
Back to 38 | Zieria lasiocaulis |
| 40 | Midvein on lower surface of leaflets glabrous to glabrescent; primary bracts boat-shaped and caducous, leaving scars on the peduncle; calyx lobes stellate-tomentose | Zieria arborescens |
| Midvein stellate pubescent; primary bracts scale-like and persistent; calyx lobes hirsute at the base with stellate hairs, glabrescent towards the apex
Back to 37 | Zieria smithii |
