Illustration: Elliot & Jones 1984, Maconochie 1978, fig. 1. Hill 1996, fig. 24. Historical notes: Although strikingly distinctive and occurring immediately beside the main (and only) north-south highway in the Northern Territory, this species was only first recognised as recently as 1978 by Australian botanist John Maconochie. in 1978. Distinguishing features: Distinguished by the flat leaves with very large numbers of very narrow leaflets with recurved margins that are persistently tomentose below, and the slender, greyish male cones. Distribution and habitat: Abundant around the Daly River basin and north along the Finniss Range, from Katherine in the south-east to the north of Litchfield Park and near the Daly River Police station, with a somewhat disjunct population in the Spirit Hills on Bullo River station near the Weastern Australian border. Although originally described from limestone and named accordingly, this species occurs on various often non-calcareous substrates such as sandstones, sandy alluvium and aluminous schists. Conservation status: Widespread, not considered to be at risk.
Description:
Stems arborescent, to 2(-5) m tall, 16-22 cm diam. at narrowest point. Leaves deep green, semiglossy, 60-130 cm long, flat (not keeled) in section (opposing leaflets inserted at 180° on rachis), with 210-410 leaflets, with white tomentum persistent below to persistent above and below; rachis usually terminated by a spine. Petiole 18-30 cm long, pubescent, spinescent for 10-50% of length. Basal leaflets gradually reducing to spines. Median leaflets simple, strongly discolorous, 50-120 mm long, 2-4 mm wide, inserted at 70-90° to rachis, decurrent for 0-1.5 mm, narrowed to 2.5-4 mm at base (to 90-100% of maximum width), 4-6 mm apart on rachis; median leaflets section flat; margins revolute; apex acute, spinescent; midrib flat above, raised below. Cataphylls linear, soft, pilose, persistent. Pollen cones narrowly ovoid to fusiform, orange or green, 25-30 cm long, 5-7 cm diam.; microsporophyll lamina firm, not dorsiventrally thickened, 25-30 mm long, 8-10 mm wide, fertile zone 18-20 mm long, sterile apex 8-10 mm long, level, apical spine prominent, sharply upturned, 7-10 mm long. Megasporophylls 12-18 cm long, grey-tomentose and brown-tomentose; ovules 4-6, glabrous; lamina lanceolate to ovate, 20-25 mm long, 15-20 mm wide, regularly dentate, with 26-36 pungent lateral spines 2-4 mm long, 1 mm wide, apical spine distinct from lateral spines, 6-10 mm long. Seeds flattened-ovoid, 25-31 mm long, 23-30 mm wide; sarcotesta orange-brown, strongly pruinose, 2.5-3 mm thick; fibrous layer absent; sclerotesta smooth. Spongy endocarp absent.
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