| Key to the species | |
1 | Flowers mostly in pairs | 2 |
| Flowers solitary | 10 |
2 | Mericarps glabrous (sometimes hirsute in G. robertianum) and wrinkled | 3 |
| Mericarps hirsute to pilose, smooth Back to 1 | 5 |
3 | Petals 4–5 mm long; basal leaves more or less palmatifid with primary lobes divided to about halfway | Geranium molle |
| Petals 6–12 mm long; basal leaves more or less pinnatisect to ternate or palmatifid, with primary lobes divided more or less to the midrib Back to 2 | 4 |
4 | Flowers small, petals 6–9 mm long; foliage not unpleasantly aromatic | Geranium purpureum |
| Flowers large, petals 9–12 mm long; foliage strongly and unpleasantly aromatic Back to 3 | Geranium robertianum |
5 | Awn of the mericarps with conspicuous glandular hairs; seeds pale brown | Geranium dissectum |
| Awn of the mericarps with mostly non-glandular hairs and sometimes some minute glandular ones; seeds black to dark brown Back to 2 | 6 |
6 | Pedicels with hairs retrorse-appressed in the flowering stage; seeds dark brown or black with pits more or less elongated or equal-sided | 7 |
| Pedicels with hairs retrorse-reflexed or spreading, never appressed, stiff; seeds black or dark brown with large more or less equal-sided pits Back to 5 | 8 |
7 | Leaves with lobes broad; taproot branched, not turnip-like; seeds dark brown with more or less elongated pits | Geranium homeanum |
| Leaves with usually linear lobes; taproot turnip-like; seeds black or very dark brown with equal-sided pits Back to 6 | Geranium retrorsum |
8 | Stems, petioles and leaves with long, patent hairs, not rough to touch; taproot spherical to turnip-shaped | Geranium solanderi |
| Stems, petioles and leaves with short to long, coarse, recurved hairs, rough to touch; taproot thickened, tapering or turnip-shaped Back to 6 | 9 |
9 | Sepal mucro >0.5 mm long; roots thickened, branched or tapering, but not napiform; mericarps without ciliate suture margins | Geranium gardneri |
9 | Sepal mucro <0.5 mm long; roots napiform to ellipsoid, but not branched; mericarps with long-ciliate suture margins | Geranium sp. Pale pink flowers (M.Gray 5847) |
10 | Flowering stems usually shorter than the basal leaves or reduced to a single peduncle and pedicel; seeds black, smooth or with minute pits | 11 |
| Flowering stems usually longer than the basal leaves; seeds dark brown or black, pits distinct Back to 1 | 12 |
11 | Pedicels with hairs retrorse-appressed; petals oblong to narrow-elliptic, 4–8 mm long, 1–3 mm wide | Geranium brevicaule |
| Pedicels with hairs antrorse-appressed; petals obovate, 6–12 mm long, 3–5 mm wide Back to 10 | Geranium antrorsum |
12 | Taproot swollen and more or less turnip-shaped; sepals obtuse or acute to acuminate, 2–5 mm wide | 13 |
| Taproot not (or sometimes in G. sp. Pale pink flowers) turnip-shaped; sepals distinctly mucronate, 1–2.5 mm wide Back to 10 | 14 |
13 | Sepals obtuse; seeds dark brown with small obscure pits; plants softly hairy; restricted species, higher altitudes from the A.C.T. to the Kosciusko area | Geranium obtusisepalum |
| Sepals acute to acuminate; seeds black, with coarse pits; plants hirsute; widespread species Back to 12 | Geranium solanderi |
14 | Petals 13–15 mm long; peduncle and pedicel together c. 8 cm long | Geranium neglectum |
| Petals 3.5–6 mm long; peduncle and pedicel together less than 5 cm long Back to 12 | 15 |
15 | Petals completely white; seeds black with large pits | Geranium graniticola |
| Petals almost always pink or tinged with pink, or if completely white then the seeds dark brown with small pits Back to 14 | 16 |
16 | Stems, petioles and leaves with short to long, coarse, recurved hairs, often rough to touch | 17 |
| Stems, petioles and leaves with short, soft spreading to recurved or appressed hairs, not rough to touch Back to 15 | Geranium potentilloides |
17 | Sepal mucro >0.5 mm long; roots thickened, branched or tapering, but not napiform; mericarps without ciliate suture margins | Geranium gardneri |
| Sepal mucro <0.5 mm long; roots napiform to ellipsoid, but not branched; mericarps with long-ciliate suture margins Back to 16 | Geranium sp. Pale pink flowers (M.Gray 5847) |