The Cycad Pages
Cycas basaltica

Cycas basaltica C.A. Gardner, "Bull. Woods Forests Dept., Western Australia 32: 31" (1923).
"TYPE: Australia, Western Australia, Lawley River, Kimberley, 27 July 1921, C.A. Gardner 1490 (holo PERTH; iso K)."

Etymology: From its occurrence on basaltic lithologies.

Illustration: Hill 1996, fig. 27.

Historical notes: Cycas basaltica was described in 1923 by Western Australain Government Botanist Charles A. Gardener on the basis of notes he made and specimens he collected on the government-sponsored Kimberley Eploration Expedition in 1921. Schuster (1932) regarded it as a variety of C. media, and de Laubenfels and Adema (1998) included it in the synonymy of C. normanbyaba. Most Australian treatments have been more rational in recognising it as the distinct species that it is (Maconochie, Kennealey).

Distinguishing features: Distinguished by the flat leaves with perpendicular, broad, white-tomentose but non-glaucous leaflets with slightly recurved margins.

Distribution and habitat: A widespread species in the northern Kimberley region of Western Australia, from offshore islands west of Port Warrender to around Kalumburu. All known occurrences are on skeletal red or grey clays on stony basalt slopes. Populations on the southern parts of the Mitchell Plateau are intergradational with C. lane-poolei.

Conservation status: Not considered to be at risk.


Stems arborescent, to 2(-4) m tall, 15-23 cm diam. at narrowest point.

Leaves grey-green to deep green, semiglossy (when mature), 80-125 cm long, flat (not keeled) in section (opposing leaflets inserted at 180° on rachis), with 140-210 leaflets, with white tomentum persistent below; rachis consistently terminated by paired leaflets. Petiole 8-20 cm long, pubescent, spinescent for 5-50% of length (often only 2-3 distal spines). Basal leaflets gradually reducing to spines, 1 mm long.

Median leaflets simple, strongly discolorous, 90-180 mm long, 5.5-9.5 mm wide, inserted at 70-80° to rachis, decurrent for 1.5-5 mm, narrowed to 4-6.5 mm at base (to 65-75% of maximum width), 6-13 mm apart on rachis; median leaflets section flat; margins flat, or slightly recurved; apex acute, spinescent; midrib flat above, raised below.

Cataphylls linear, soft, pilose, 70-130 mm long, persistent.

Pollen cones narrowly ovoid, orange to brown, 18-24 cm long, 7-9 cm diam.; microsporophyll lamina firm, not dorsiventrally thickened, 25-35 mm long, 11-15 mm wide, fertile zone 20-24 mm long, sterile apex 7-13 mm long, deflexed, apical spine prominent, sharply upturned, 5-11 mm long.

Megasporophylls 17-24 cm long, brown-tomentose; ovules 2-6, glabrous; lamina lanceolate, 50-90 mm long, 14-19 mm wide, regularly dentate, with 6-20 soft lateral spines 2-4 mm long, 2-3 mm wide, apical spine distinct from lateral spines, 20-35 mm long.

Seeds flattened-ovoid, 27-31 mm long, 26-30 mm wide; sarcotesta orange-brown, strongly pruinose, 2-3 mm thick; fibrous layer absent; sclerotesta smooth. Spongy endocarp absent.

The Cycad Pages

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Written and maintained by Ken Hill 1998-2010
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