Australian Tropical Rainforest Plants - Online edition
Archontophoenix maxima Dowe
Dowe, J.L. & Hodel, D.R. (1994) Austrobaileya 4(2): 235, fig. 1 A1-A3. Type: Queensland. Cook District: Cultivated [ex Walsh River, Feb 1975 Irvine 1168 (QRS)], property of A.K. Irvine, Atherton, 4 May 1993, Dowe 106 (holo: BRI).
Walsh River Palm
Palm up to 22 m tall. Trunk up to 30 cm DBH with prominent leaf scars, becoming fissured with age and expands to 50 cm at the base, stepped in the basal portion.
Leaves 8-11, up to 5 m long, ascending, held straight with only a moderate lateral twist, with up to 85 pairs of pinnae per side. Crownshaft 74-145 cm long, mid green with sparse black persistent scales, thickly textured and heavily fibrous, only slightly bulged at the base. Petiole 0-20 x 9 cm, glabrous, flat to shallowly concave above. Rachis to 340 cm long, ridged above becoming sharp in the front portion. Pinnae to 90 x 7 cm, dark green adaxially, silvery on the abaxial surface. Midrib prominent on both surfaces, brittle, thick, yellow/green; up to 9 secondary ribs prominent on the abaxial surface; pinnae always rigid.
Inflorescence 80-140 x 100 cm, smooth, axes cream/green initially turning green. Prophyll up to 105 cm long, winged with a beak at the apex and thickly textured; peduncular bract up to 80 cm long and strongly beaked at the apex, with a papery texture. Peduncle 16 x 6.8-12 x 2.8-4 cm, curved downward when fruit mature and with prominent lateral 'horns' in the lower portion. Rachis with 18-23 main branches, angular with the basal branches up to 8 x 2 cm. Rachillae up to 40 cm long and stiffly pendulous becoming only mildly zig-zagged in the front part. Triads widely spaced with the paired staminate flowers in the front part. Floral bracts low and rounded. Staminate flowers 5-6 x 10-11. Petals 5-6 x 2-2.5 mm, fleshy, falcate and pointed. Stamens 11-16, ca. as long as petals. Filaments curved with the connective very short. Pistillode ca. as long as the stamens, apex shallowly lobed.
Fruit conic-ovoid, 11-15 x 7-12 mm and red at maturity; stigmatic remains moderately protrusive. Epicarp smooth, waxy and glossy. Mesocarp fibres moderately thick, to 1 mm wide, flat and sparingly branched. Endocarp brittle. Mesocarp fibres not imbedded in endocarp. Seed globose, up to 6 mm diameter Raphe fibres deeply imbedded and strongly adherent. Endosperm deeply ruminate.
Features not available.
Occurs in NEQ on the Atherton Tableland. Altitudinal range 800-1200 m. Grows along drainage lines in rainforest and riparian rainforest, wet sclerophyll forest and Casuarina-dominated forest on basalt soils.
Distinguished by: undersurface of pinnae with silver-grey scales, ramenta (large irregular scales on midrib) lacking; perianth white-cream or light green, fruit conic-ovoid, 11-15 mm; mesocarp fruit fibres to 1 mm, flat, sparingly branched.