This species is close to E. horridus, from which it is distinguished by the entire lower leaflets and the yellowish cones with wrinkled facets. Leaves also tend to be less intensely blue, although this character is variable within the species and with leaf age. Leaflets of E. horridus are also twisted out of the plane of the leaf, and not so in E. trispinosus. The blue-leaved species of the Cape Province have discolorous leaves with stomata on the undersurfaces only, in contrast to the blue-leaved species of Transvaal, which all have stomata on both surfaces of the leaflets.
Plants arborescent; stem 1 m tall, 25-30 cm diam.
Leaves 75-125 cm long, blue or silver, dull, slightly keeled to flat in section (opposing leaflets inserted at 150-180° on rachis); rachis blue, straight with last third sharply recurved, not spirally twisted; petiole straight, with no prickles; leaf-base collar prominent; basal leaflets not reducing to spines.
Leaflets lanceolate, weakly discolorous, not overlapping, with 1-2 lobes on upper and median leaflets, insertion angle horizontal; margins flat; upper margin entire (no teeth); lower margin entire (no teeth); median leaflets 10-18 cm long, 15-25 mm wide.
Pollen cones 1, fusiform, yellow, 25-35 cm long, 7-8 cm diam.
Seed cones 1, ovoid, yellow, 40-50 cm long, 18-20 cm diam.
oblong, 30-35 mm long, 18-20 mm wide, sarcotesta red.
Distribution & Habitat
Eastern Cape Province, South Africa, in arid low succulent shrubland on rocky ridges and slopes.
Common Name: Bushman's River cycad. Latin tri-, three and spinosus, spines, from the 3-lobed leaflets. Described as a variety of E. horridus in 1863 by English botanist J.D. Hooker, later raised to the rank of species by South African botanist R. Allen Dyer.
References & Acknowledgements:
- Images - Ken Hill
- Royal Botanic Gardens Sydney