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The Cycad Pages
Encephalartos horridus

Encephalartos horridus (Jacq.) Lehm., Pugill. 6: 14 (1834). BAS

Encephalartos horridus var. tridens Miq., Monogr. Cycad.57 (1842).

TYPE: ?
Encephalartos horridus var. van hallii (deVriese) J. Schust., "in Otto & Dietrich., Allg. Gartenz. 326" (1838).
TYPE: ?


Photo Ken Hill

Etymology: Latin horridus, horrible, from the very stiff and spiny leaflets.

Literature:

Illustrations:

Vernacular:

Historical notes: Described as a species of Zamia in 1801 by French botanist -- Jaquin.

Distinguishing features: This species is closest to E. trispinosus, from which it is distinguished by the deeply lobed lower leaflets and the grey-green cones with brown tomentum and smooth facets. Leaves also tend to be more intensely blue, although this character is variable within the species and with leaf age. Leaflets 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.

Distribution and habitat: Eastern Cape Province, South Africa, arid shublands with succulents on shallow soils on ridges and slopes.

Conservation: 1997 IUCN Red List of Threatened Plants category V.
Photo Ken Hill

Description:

Plants arborescent; stem 0.5 m tall, 30 cm diam.

Leaves 100 cm long, blue or silver, dull, flat (not keeled) in section (opposing leaflets inserted at 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 to overlapping upwards, with 2-3 lobes on most leaflets, insertion angle horizontal to obtuse (45-80°); margins flat, or recurved; upper margin entire (no teeth); lower margin entire (no teeth); median leaflets 10 cm long, 25-40 mm wide.

Pollen cones 1, ovoid, red to brown, 20-40 cm long, 6-12 cm diam.

Seed cones 1, ovoid, red to brown, 25-40 cm long, 15-20 cm diam.

Seeds oblong, 30-35 mm long, 20-25 mm wide, sarcotesta red.
Photo Ken Hill


The Cycad Pages

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Written and maintained by Ken Hill 1998-2010
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