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The Cycad Pages
Cycas angulata

Cycas angulata R. Br., Prodr. 1: 348 (1810).
"TYPE: Australia, ""New Holland, North Coast""R. Brown s.n. (holo BM; iso K)."


Photo Ken Hill
Etymology: From Latin angulatus, angled, referring to the insertion of the leaflets on the rachis.

Literature: Gaudichaud 1829, Stearn 1976

Illustrations: Miquel 1842 Hill 1992, fig. 17.

Historical notes: The type specimens bear no original label, and are numbered 3106 in Bennett's series (p.p. - Bennett gave all Brown Cycas collections this number, including the type of C. media, below). Brown cited it only as `(T.) v.v.', `T.' (`littus intra Tropicum') representing tropical Australia between the Endeavour River and Arnhem Bay. Probably collected on 3-4 Dec 1802 from Bountiful Island, near Mornington Island in the Gulf of Carpentaria (Groves & Moore 1989).

Distinguishing features: Distinguished from other Australian species by the very robust habit, the abundant, long, strongly pungent, thinly sericose cataphylls, the keeled leaves with long, narrow, greyish leaflets arranged at a relatively low angle to the rachis, the large, subglobular male cone, and the long megasporophylls with large numbers of large seeds and a relatively short, finely toothed lamina.

Distribution and habitat: A distinctive localised species, known from the lower reaches of the Wearyan, Foelsche and Robinson Rivers near Borroloola, and from the Bountiful Island group further east in the Gulf of Carpentaria. In both areas it occurs in open grassy woodland or grassland on flat country on sandy alluvium.

This species forms local cycad-dominated woodlands in parts of the Northern Territory, but is less abundant in Queensland, where it is known at present only from offshore islands.

Conservation status: Not considered to be at risk.
Photo Ken Hill
Photo Ken Hill

Description:

Stems arborescent, to 5(-12) m tall, 15-25 cm diam. at narrowest point.

Leaves grey-green (bluish when new), semiglossy, 110-170 cm long, moderately keeled (opposing leaflets inserted at 90-135° on rachis), with 180-320 leaflets, with brown tomentum shedding as leaf expands; rachis usually terminated by paired leaflets. Petiole 28-52 cm long, glabrous or pubescent, spinescent for 30-90% of length. Basal leaflets not gradually reducing to spines.

Median leaflets simple, weakly discolorous, 140-230 mm long, 4.5-6.5 mm wide, inserted at 40-60° to rachis, decurrent for 2-4 mm, narrowed to 3-5 mm at base (to 70-80% of maximum width), 6-9 mm apart on rachis; median leaflets section slightly keeled; margins recurved; apex aristate, spinescent; midrib flat above, raised below.

Cataphylls linear, pungent, pilose, 130 mm long, persistent.

Pollen cones globose, orange, 20-25 cm long, 12-15 cm diam.; microsporophyll lamina firm, not dorsiventrally thickened, 45-60 mm long, 15-20 mm wide, fertile zone 30-40 mm long, sterile apex 15-20 mm long, level, apical spine prominent, sharply upturned, 20-30 mm long.

Megasporophylls 25-50 cm long, grey-tomentose and brown-tomentose; ovules 6-12, glabrous; lamina lanceolate, 50-105 mm long, 25-35 mm wide, regularly dentate, with 34-50 pungent lateral spines 0.5-2 mm long, 1 mm wide, apical spine distinct from lateral spines, 12-38 mm long.

Seeds ovoid, 45-60 mm long, 40-50 mm wide; sarcotesta orange-brown, not pruinose or slightly pruinose, 3-4 mm thick; fibrous layer absent; sclerotesta smooth. Spongy endocarp absent.
Photo Ken Hill


The Cycad Pages

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Written and maintained by Ken Hill 1998-2010
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