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The Cycad Pages
Encephalartos dolomiticus

Encephalartos dolomiticus Lavranos & D.L. Goode, Bull. Jard. Bot. Belg. 58: 219-224 (1988). H—NH
"TYPE: Republic of South Africa, Transvaal, Drakensberg Mountains, N of Penge and S of The Downs, alt ca 1200, 1975, A. Prozeski s.n. (holo NH iso MO)."


Photo Ken Hill

Etymology: Dolomite, a type of magnesium-rich limestone, with the Latin suffix iticus, --

Literature:

Illustrations:

Vernacular:

Historical notes: Described in 1988 by South African botanists - Lavranos and Douglas Goode, who recognised that the blue-leaved Transvaal cycads previously all included in E. eugene-maraisii fell into a number of clearly morphologically distinct and geographically separated populations (see also E. dyerianus and E. middelbergensis). Similar observations were published more or less simultaneously by Robbertse et al. (1990), resulting in creation of the redundant names E. graniticola and E. verrucosus. E. hirsutus is another more recently recognised member of this group.

Distinguishing features: Distinguished within a group of blue-leaved Transvaal species by the untidily twisted leaves with recurved tips, the entire leaflets, the lower 1-2 pairs of leaflets reducing in size but remaining entire, a clear petiole 9-14 cm long, and green, glabrous cones. This group of species is distinguished from the blue-leaved species of the Cape Province (E. lehmannii and allies) by the almost concolorous leaves with stomata on both surfaces.

Distribution and habitat: Southern Transvaal Province, South Africa, restricted to a very small population in the Drakensberg Mountains, in grassland on shallow soils over dolomite ridges

Conservation: 1997 IUCN Red List of Threatened Plants category E.

Description:

Plants arborescent; stem 2 m tall, 40 cm diam.

Leaves 60-80 cm long, blue or silver, dull, moderately keeled; rachis blue, straight, stiff, slightly twisted in some leaves; petiole straight, with 1-6 prickles; leaf-base collar prominent; basal leaflets reducing to spines.

Leaflets lanceolate, concolorous, not lobed, insertion angle obtuse (45-80°); margins flat; upper margin entire (no teeth); lower margin entire (no teeth) to lightly toothed (1-3 teeth); median leaflets 12-17 cm long, 10-14 mm wide.

Pollen cones 1-4, narrowly ovoid, green, 35-50 cm long, 10 cm diam.

Seed cones 1-4, ovoid, blue-green, 30-45 cm long, 18-25 cm diam.

Seeds oblong, 30-35 mm long, 18-20 mm wide, sarcotesta yellow.


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Written and maintained by Ken Hill 1998-2010
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