Leaves alternate, generally small and often clustered, the lower surface usually whitish tomentose but often concealed by the revolute margins.
Flowers ± sessile, crowded at the ends of branchlets into spike-like inflorescences or clustered into small heads, each flower surrounded by persistent brown bracts. Flowers usually small, mostly hairy without, glabrous within. Hypanthium tubular, ± fused to the base of the ovary but free and produced above the ovary and disc, persistent. Sepals short or ± equal to the length of the hypanthium, persistent. Petals hooded, usually enclosing the anthers. Anthers usually ± sessile on rim of hypanthium. Disc annular.
| | Key to the species | |
| 1 | Flowers in terminal heads or head-like clusters; plants lacking numerous short lateral branchlets, not spinose; leaves mostly more than 5 mm long and generally more than 2 mm wide (narrower in Cryptandra ericoides and some C. scortechinii) | 2 |
| Flowers in spike-like inflorescences, usually on short lateral branchlets; many short lateral branches present, sometimes spinose; leaves mostly less than 5 mm long and usually ± 2 mm wide | 6 |
| 2 | Leaves obovate to obcordate, whitish or rusty-tomentose on both surfaces | Cryptandra leucophracta |
| Leaves ovate to linear, mature leaves (excluding floral leaves) more or less glabrous on upper surface
Back to 1 | 3 |
| 3 | Leaves linear, margins strongly revolute, lower leaf surface not visible | Cryptandra ericoides |
| Leaves not linear, margins flat or recurved but lower leaf surface at least partly visible
Back to 2 | 4 |
| 4 | Leaves oblong to narrow-oblong, mostly 10–30 mm long; floral leaves with upper surface whitish tomentose, mostly ovate to elliptic | Cryptandra sp. Floriferous (W.R.Barker 4131) |
| Leaves ovate to narrow-lanceolate, rarely more or less oblong, mostly 8–15 mm long; floral leaves neither whitish tomentose on upper surface nor ovate to elliptic
Back to 3 | 5 |
| 5 | Leaves mostly more than 3 mm wide; flowers in few- to many-flowered terminal clusters, brown bracts surround individual flowers | Cryptandra buxifolia |
| Leaves usually less than 3 mm wide; flowers in dense terminal heads, brown bracts surround heads as well as individual flowers
Back to 4 | Cryptandra scortechinii |
| 6 | Sepals at least as long as the hypanthium | 7 |
| Sepals much shorter than the hypanthium
Back to 1 | 9 |
| 7 | Sepals spreading when the flowers open, stamens exserted, filaments erect, c. 1 mm long | Cryptandra longistaminea |
| Sepals not spreading and exposing the stamens, anthers almost sessile
Back to 6 | 8 |
| 8 | Flowers 5–7 mm long, sepals 2–4 mm long; bracts more or less enclosing the hypanthium | Cryptandra propinqua |
| Flowers 2–4 mm long, sepals 1–2 mm long; bracts only covering base of hypanthium
Back to 7 | Cryptandra amara |
| 9 | Flowers densely whitish tomentose | Cryptandra lanosiflora |
| Flowers not densely whitish tomentose, hypanthium partly glabrous or with more or less appressed hairs
Back to 6 | 10 |
| 10 | Hypanthium glabrous in basal half, silky-pubescent above; smaller lateral branches nearly all less than 10 mm long and spinescent; bracts below flower | Cryptandra spinescens |
| Hypanthium hairy on outer surface; branchlets mostly more than 15 mm long, sometimes spinescent; bracts usually enclosing lower part of hypanthium in flower
Back to 9 | 11 |
| 11 | Flowers in more or less dense heads, bracts acuminate; hypanthium covered with long appressed hairs; leaves more or less terete, 4–10 mm long | Cryptandra ericoides |
| Flowers solitary or in few- to many-flowered spike-like clusters, bracts broad and obtuse; hypanthium covered with only short or with short and some longer appressed hairs; leaves mostly less than 5 mm long, more or less terete to oblong or more or less obovate or elliptic
Back to 10 | Cryptandra amara |
