Etymology: Greek, platy-, broad, and rhachis, leaf axis above the petiole, from the strongly flattened rachis. Historical notes: Bailey originally used the spelling "platyrhachis", later amending this to "platyrachis". Both spellings are legitimate, and Johnson (1959) recommended that the later spelling of "platyrachis" be used. Distinguishing features: Distinguished by the short, spirally twisted leaves with short, broad petioles and very broad leaflets. Distribution and habitat: Central Queensland, the Blackdown Tableland and Expedition Range area. Scattered and locally abundant in dry sclerophyll forest on flat plateau country on sandstone. Conservation status: Not considered to be at risk, well conserved in Blackdown Tableland National Park (IUCN Red List category LR,lc; ROTAP category 2Rcat). Gazetted as a Rare or Threatened Plant under Queensland Nature Conservation legislation. 1997 IUCN Red List of Threatened Plants category E.
Description:
Plants acaulescent, stem 25-60 cm diam. Leaves 2-8 in crown, bright green, highly glossy to semiglossy, 45-80 cm long, moderately keeled, with 36-60 leaflets; rachis not spirally twisted, straight, stiff or recurved, arching stiffly downwards; petiole 15-25 cm long, straight or recurved, unarmed, 13-18 mm wide at lowest leaflets; basal leaflets not reducing to spines. Leaflets simple, strongly discolorous; margins flat; apex dentate, not spinescent; median leaflets 250-400 mm long, 12-20 mm wide. Pollen cones narrowly ovoid, 15-20 cm long, 4-4.5 cm diam.; microsporophyll lamina 18-21 mm long, 16-19 mm wide; apical spine 0-8 mm long. Seed cones ovoid, 12-17 cm long, 8-9 cm diam.; megasporophyll with an expanded peltate apex 40-50 mm wide, 20-30 mm high; apical spine 1-13 mm long. Seeds ovoid, 25-30 mm long, 20-25 mm wide; sarcotesta red.
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