Etymology:
From the Greek mega-, large, and karpos, fruit,
referring to the distinctive large seeds.
Illustration: Hill 1992, fig. 5. Historical notes: C. megacarpa has been cultivated in Australia under the name C. kennedyana, but the type of the latter name belongs to C. media (which see). Distinguishing features: Distinguished from other Australian species by the keeled, grey to green leaves with broad leaflets, and the large non-glaucous or weakly pruinose seeds. Cataphylls are short and soft, with pilose to floccose orange-brown indumentum. Adult leaves are generally smaller and more green, the trunk is more slender, and seeds are larger than those of the similar C. ophiolitica. Distribution and habitat: Scattered and localised on clay-loam soils over various substrates, usually on sloping country in wet eucalypt forests or rainforests. This species ranges from near Mount Morgan south to near Goomeri in Queensland, occurring in locally more mesic microhabitats, becoming quite sporadic and occurring further inland in the south of the range. Populations near Mt Morgan show extensive intergradation with C. ophiolitica, but also have larger seeds than more southerly occurring plants. Conservation status: Although locally abundant, the eucalypt forest habitat of this species is not well conserved, and there is considerable risk of habitat removal for forestry and pastoral activity. 1997 IUCN Red List of Threatened Plants category V. ROTAP category 3VC.
Description:
Stems arborescent, to 3(-6) m tall, 8-14 cm diam. at narrowest point. Leaves bright green, highly glossy or semiglossy, 70-110 cm long, moderately keeled (opposing leaflets inserted at 90-135° on rachis), with 120-170 leaflets, with orange tomentum shedding as leaf expands; terminated by paired leaflets or a spine. Petiole 20-36 cm long, glabrous or pubescent, spinescent for 20-100% of length. Basal leaflets not gradually reducing to spines. Median leaflets simple, strongly discolorous, 120-200 mm long, 5-7.5 mm wide, inserted at 40-70° to rachis, decurrent for 2-3 mm, narrowed to 2.5-4 mm at base (to 40-60% of maximum width), 5-12 mm apart on rachis; median leaflets section flat, or slightly keeled; margins slightly recurved; apex aristate, not spinescent; midrib flat above, raised below. Cataphylls linear, pungent, pilose, 70 mm long, persistent. Pollen cones ovoid, orange, 18 cm long, 7 cm diam.; microsporophyll lamina firm, not dorsiventrally thickened, 32 mm long, 11 mm wide, fertile zone 25 mm long, sterile apex 7 mm long, deflexed, apical spine prominent, sharply upturned, 5-8 mm long. Megasporophylls 14-25 cm long, grey-tomentose or brown-tomentose; ovules 2-4, glabrous; lamina lanceolate, 40-70 mm long, 15-32 mm wide, regularly dentate, with 18-26 pungent lateral spines 3-6 mm long, 1-2 mm wide, apical spine distinct from lateral spines, 8-20 mm long. Seeds flattened-ovoid, 38-50 mm long, 35-45 mm wide; sarcotesta orange-brown, not pruinose or slightly pruinose, 3.5-5 mm thick; fibrous layer absent; sclerotesta smooth. Spongy endocarp absent.
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