Description: Erect to spreading annuals or biennials.
Leaves opposite.
Flowers bisexual, sessile in head-like axillary spikes or clusters. Bracts spinescent, spreading in fruit. Perianth segments 4, rigid, lanceolate, the bases enclosing the fruit; outer 2 ± keeled, hairy at base; outermost segment spinescent, apex reflexed in fruit; next segment shortly spinescent; 2 innermost segments acute. Stamens 2 or 4, filaments fused at base into a short tube, alternating with scales or staminodes. Stigma capitate.
Fruit membranous, indehiscent, enclosed in the persistent perianth.
Distribution and occurrence: World: 2 species, endemic Australia. Australia: Qld, N.S.W.
The two species are normally distinguished on the number of stamens. This character does seem to vary sometimes on the one plant and, as most of the other characters overlap, there does seem to be some doubt about the present division.
Text by S. W. L. Jacobs & L. Lapinpuro
Taxon concept:
| | Key to the species | |
| 1 | Stamens 2; leaves ovate, elliptic to obovate or oblanceolate, 15–25 mm long, 4–13 mm wide | Nyssanthes diffusa |
| Stamens 4; leaves elliptic to oblong to lanceolate, 20–75 mm long, 15–20 mm wide | Nyssanthes erecta |
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