Leaves alternate (or rarely opposite), frequently fleshy or succulent, terete, semiterete or flattened.
Flowers bisexual and/or unisexual, axillary, solitary or paired, occasionally gathered towards the ends of the branches into leafy spike-like pseudo-inflorescences. Perianth 5-lobed with or without a tubular base. Stamens 5, opposite perianth lobes. Ovary ± globose; style with 2 or 3 stigmas.
Fruit consisting of an utricle surrounded by a variously enlarged fruiting perianth with a vertical tube and wings or wing-like outgrowths arising from the base of the perianth lobes. The wings sometimes variously adorned with appendages. Seed horizontal to oblique. Widespread, usually in drier regions.
| | Key to the species | |
| 1 | Fruit with 5 more or less horizontal wings surrounding the upper perianth | 2 |
| Fruit with a single wing surrounding the upper perianth; appendages or accessory wings may also be present | 8 |
| 2 | Fruit with erect appendages arising from the upper perianth | 3 |
| Fruit without erect appendages
Back to 1 | 4 |
| 3 | Wings flat, truncate or rounded at apex; fruit shortly woolly | Maireana lobiflora |
| Wings spine-like; fruit densely silky-woolly
Back to 2 | Maireana sclerolaenoides |
| 4 | Fruit wheel-like, with 5 flattened T-shaped lobes, pubescent with curled hairs | Maireana cheelii |
| Fruit with lobed wing or 5 fan-shaped to crescentic lobes; lobes glabrous or hairy
Back to 2 | 5 |
| 5 | Wing of fruit silky-woolly, 5-lobed | Maireana eriantha |
| Wing(s) of fruit glabrous
Back to 4 | 6 |
| 6 | Wing(s) thin, obovate to fan-shaped | 7 |
| Wings small, imbricate, crescentic, incurved or inflated on margins
Back to 5 | Maireana enchylaenoides |
| 7 | Leaves not attenuate at base, often hairy; wing simple and finely crenate if present | Maireana microphylla |
| Leaves attenuate at base, glabrous; wing of 5 free lobes
Back to 6 | Maireana brevifolia |
| 8 | Fruit either less than 5 mm diam. and more or less densely silky-pilose or mostly more than 5 mm diam. and then fruit glabrous with large rounded soft spongy tube | 9 |
| Fruit not combining the above characters
Back to 1 | 13 |
| 9 | Fruit less than 5 mm diam., more or less densely silky-pilose; tube mostly flat and continuous with the narrow wing | 10 |
| Fruit (including wing) mostly over 5 mm diam., glabrous with large rounded soft spongy tube; upper perianth more or less flat
Back to 8 | 12 |
| 10 | Upper surface of fruit with an erect cup-shaped appendage | Maireana coronata |
| Fruit with either a central raised pentagonal area or 5 narrow radial ridges
Back to 9 | 11 |
| 11 | Fruit 2.5–4 mm diam., upper surface with a central raised pentagonal area | Maireana pentagona |
| Fruit c. 4 mm diam., upper surface with 5 narrow radial ridges
Back to 10 | Maireana ciliata |
| 12 | Branches with a pale fawn indumentum of dendritic hairs; horizontal wing not decurrent on tube | Maireana campanulata |
| Branches with a white woolly indumentum of simple hairs; horizontal wing attached by a short decurrent wing to tube
Back to 9 | Maireana spongiocarpa |
| 13 | Either 1–5 vertical wings on the tube or above the horizontal wing, or vertical appendages present on upper perianth, or vertical wings on tube and appendages on upper perianth absent and then the plant glabrous apart from axillary hair tufts | 14 |
| Vertical wings and appendages as above absent, plants variously hairy
Back to 8 | 21 |
| 14 | One to five vertical wings on the tube or above the horizontal wing | 15 |
| No vertical wings on tube
Back to 13 | 18 |
| 15 | Plant glabrous or almost so | Maireana triptera |
| Plant hairy, at least on branches
Back to 14 | 16 |
| 16 | Leaves villous; perianth lobes erect and longer than the tube | Maireana schistocarpa |
| Leaves glabrous; perianth lobes not erect
Back to 15 | 17 |
| 17 | Vertical wings running length of tube and united at apex with horizontal wing; perianth lobes prominently woolly-ciliate | Maireana erioclada |
| Vertical wings often present only towards base of tube; perianth lobes arched and prominently tomentose
Back to 16 | Maireana pentatropis |
| 18 | Vertical appendages present on upper perianth | Maireana lanosa |
| No vertical appendages present above the wing
Back to 14 | 19 |
| 19 | Upper perianth convex; leaves linear to semiterete, shortly spurred at base; fruit straw-coloured when dry | Maireana aphylla |
| Upper perianth more or less flat; leaves terete; fruit dark brown to black when dry
Back to 18 | 20 |
| 20 | Leaves not fleshy; stem sparsely hairy with short, straight appressed hairs | Maireana microphylla |
| Leaves fleshy; stem sparsely hairy with short woolly hairs
Back to 19 | Maireana decalvans |
| 21 | Wing of fruit glabrous | 22 |
| Wing of fruit pubescent above
Back to 13 | 44 |
| 22 | Upper perianth flat or slightly concave or convex | 23 |
| Upper perianth columnar with large erect lobes
Back to 21 | 43 |
| 23 | Tube of fruit abruptly narrowed at base into a prominent terete stipe-like base 1–3 mm long | 24 |
| Tube not forming a prominent stipe-like base
Back to 22 | 25 |
| 24 | Upper perianth convex, open in centre to expose utricle | Maireana aphylla |
| Upper perianth flat or slightly sunken, completely covering utricle
Back to 23 | Maireana appressa |
| 25 | Tube expanded into a hollow spongy base | Maireana excavata |
| Tube not, or scarcely, expanded at base
Back to 23 | 26 |
| 26 | Wing of fruit with radial slit | 27 |
| Wing of fruit continuous, without a radial slit; leaves semiterete
Back to 25 | 40 |
| 27 | Leaves, branches and flowers closely tomentose with dendritic hairs; leaves obovate; tube and convex upper perianth of fruit pubescent | Maireana astrotricha |
| Leaves and branches with more or less simple hairs or glabrous
Back to 26 | 28 |
| 28 | Fruit large, wing c. 15 mm diam. or more; tube thick-walled, turbinate | Maireana georgei |
| Fruit with wing 5–14 mm diam., tube not thick-walled
Back to 27 | 29 |
| 29 | Tube of fruit pubescent; upper perianth more or less flat; leaves obovate to oblong, succulent | Maireana sedifolia |
| Tube of fruit glabrous; leaves various
Back to 28 | 30 |
| 30 | Leaves flattened, linear to obovate | Maireana villosa |
| Leaves terete, semiterete or obovate
Back to 29 | 31 |
| 31 | Fruit produced into a short, terete, hollow stipe-like base, straw-coloured when dry | 32 |
| Fruit without a stipe-like base
Back to 30 | 33 |
| 32 | Open, divaricately branched shrub; branches striate and often spinescent; upper perianth convex and open in centre | Maireana aphylla |
| Branches more or less ascending, neither spinescent nor striate; upper perianth flat or sunken and completely covering utricle
Back to 31 | Maireana appressa |
| 33 | Upper perianth with a convex disc, open in centre | 34 |
| Upper perianth more or less flat, concave, or if convex then closed in centre
Back to 31 | 35 |
| 34 | Stem striate; leaves sessile, woolly to glabrescent | Maireana aphylla |
| Stem not obviously striate, leaves narrowed at base, glabrous
Back to 33 | Maireana rohrlachii |
| 35 | Upper perianth tomentose | 36 |
| Fruit glabrous or sparsely villous
Back to 33 | 37 |
| 36 | Wing with fine but obvious radiating veins | Maireana radiata |
| Wing of fruit with indistinct or no visible veins
Back to 35 | Maireana integra |
| 37 | Branches sparsely strigose, sparsely villous or somewhat woolly when very young; leaves slender, 2–10 mm long; wing of fruit finely crenate; flowers in leafy spike-like inflorescences | Maireana microphylla |
| Branches more or less tomentose, at least on young parts, rarely glabrous; flowers not in leafy spike-like inflorescences
Back to 35 | 38 |
| 38 | Leaves tomentose; fruit straw-coloured when dry | Maireana appressa |
| Leaves glabrous or sparsely villous; fruit brown when dry
Back to 37 | 39 |
| 39 | Upper perianth closed in centre; tube firm | Maireana microcarpa |
| Upper perianth open in centre, exposing the utricle; tube weak
Back to 38 | Maireana decalvans |
| 40 | Fruit large, wing c. 15 mm diam., tube turbinate, smooth | Maireana turbinata |
| Fruit small, wing 11 mm or less in diam., tube hemispherical to cupular
Back to 26 | 41 |
| 41 | Leaves 2–5 mm long, appressed on younger branches; wing 4–6 mm diam | Maireana ovata |
| Leaves more than 5 mm long, spreading; wing usually 8–10 mm diam
Back to 40 | 42 |
| 42 | Upper perianth pubescent | Maireana integra |
| Upper perianth glabrous, or almost so, apart from the ciliate lobes
Back to 41 | Maireana tomentosa |
| 43 | Leaves 2–6 mm long, shortly pubescent; no vertical wing on tube | Maireana pyramidata |
| Leaves 5–12 mm long, appressed-villous; tube with a narrow vertical wing
Back to 22 | Maireana schistocarpa |
| 44 | Upper perianth erect and columnar | Maireana schistocarpa |
| Upper perianth not erect and columnar
Back to 21 | 45 |
| 45 | Perianth tube thin-walled, base expanded into a hollow stipe; leaves semiterete, c. 10 mm long | Maireana trichoptera |
| Perianth tube with a hard boss-like base; leaves narrow-elliptic to narrow-obovate, mostly 7–12 mm long
Back to 44 | Maireana humillima |
