Solanum echinatum, Brown, 1810

Bean, A. R., 2012, A taxonomic revision of the Solanum echinatum group (Solanaceae), Phytotaxa 57 (1), pp. 33-50 : 34-35

Key to species in the Solanum echinatum group

1a. Stellate hairs 0.3–0.6 mm diameter on branchlets and petioles, central ray 0.3–1.2 times length of lateral rays; all stellate hairs on fruiting calyx with stalks <0.5 mm long; proto-prickles absent ........................................................ 2

1b. Stellate hairs 0.6–1.1 mm diameter on branchlets and petioles, central ray 1–1.8 times length of lateral rays; some of the stellate hairs on fruiting calyx with stalks> 0.8 mm long, proto-prickles sometimes present ............................... 6

2a. Prickles on fruiting calyx 40–70, with hairs extending to distal half of prickle; leaves broadly-ovate, 2.1–3.8 cm long ............................................................................................................................................................. S. medicagineum

2b. Prickles on fruiting calyx>100, with stellate hairs only near base; leaves ovate, 3–13.3 cm long ............................. 3

3a. Corolla 12–16 mm long; filaments 2–2.8 mm long ..................................................................................................... 4

3b. Corolla 7–11mm long; filaments 1–1.9 mm long ......................................................................................................... 5

4a. Branchlet prickles 0.5–3 mm long, 6–9 times longer than wide; prickles absent from petioles; stellate hairs of lower leaf surface 0.3–0.4 mm diameter; inflorescence 3–5-flowered .................................................................. S. wilkinsii

4b. Branchlet prickles 2–8 mm long, 10–13 times longer than wide; prickles present on petioles; stellate hairs of lower leaf surface 0.5–0.7 mm diameter; inflorescence 6–11-flowered .............................................................. S. fecundum

5a. Upper leaf surface sparsely or moderately stellate-hairy, with central ray of stellate hairs 0.2–0.5 times length of laterals; branchlet prickles 1–23 per decimetre; style eccentric .................................................................. S. lapidosum

5b. Upper leaf surface very densely stellate-hairy, with central ray of stellate hairs 0.7–1.0 times length of laterals; branchlet prickles 50–130/decimetre; style erect...................................................................................... S. rhaphiotes

6a. Petioles 25–55% of lamina length; branchlet prickles 100–660 per decimetre; leaf margins often repand; calyx lobes 2.5–6 mm long at anthesis ........................................................................................................................ S. echinatum

6b. Petioles 55–115% of lamina length; branchlet prickles 3–80 per decimetre; leaf margins entire; calyx lobes 1–2.5 mm long at anthesis ........................................................................................................................................ S. lucani