1	"Plant with branched hairs"	2
1	"Plant glabrous, or with papillae or simple hairs"	7
2	"Hairs sessile, bifid"	"Stenopetalum nutans"
2	"Hairs irregularly branched or stellate"	3
3	"All parts of plant densely hairy"	4
3	"Upper parts of plant glabrous to sparsely hairy"	5
4	"Plants slender annuals; silicula 4–7 mm long; ovules 10–20 per locule; seeds tuberculate"	"Stenopetalum velutinum"
4	"Plants perennial with a corky rootstock, silicula 7–11 mm long; ovules 3–10 per locule; seeds smooth"	"Stenopetalum decipiens"
5	"Plants slender annuals; leaves of lower stem pinnatisect to trisect"	"Stenopetalum lineare"
5	"Plants slender perennials, rootstock not corky; leaves entire, remotely dentate or rarely trisect"	6
6	"Upper parts of plant glabrous"	"Stenopetalum lineare"
6	"Upper parts of plant sparsely hairy, chiefly at nodes"	"Stenopetalum saxatile"
7	"Fruiting pedicels erect to spreading"	8
7	"Fruiting pedicels pendulous, rarely horizontal"	9
8	"Leaves entire to dentate; ovules 6–10 per locule"	"Stenopetalum filifolium"
8	"Leaves pinnasect basally, reducing to entire; ovules 8–15 per locule"	"Stenopetalum anfractum"
9	"Plants covered in simple hairs, petals short and broad"	"Stenopetalum robustum"
9	"Plants glabrous, petals fine and tapering"	10
10	"Fruiting pedicel swollen adjacent to fruit"	"Stenopetalum salicola"
10	"Fruiting pedicel not swollen adjacent to fruit"	11
11	"Petals 3–6 mm long, often cleistogamous"	"Stenopetalum sphaerocarpum"
11	"Petals 6–25 mm long"	12
12	"Flowering pedicels robust, 2–3 mm long, silicula 5–9 mm long, seeds c. 2 mm long"	"Stenopetalum gracile"
12	"Flowering pedicels slender, 7–20 mm long, silicula 4–5 mm long, seeds c. 1 mm long"	"Stenopetalum pedicellare"