Muir, J., a physician at Riversdale, who made a comprehensive survey of the vegetation of the Riversdale area in 1929, in addition to other researches in natural history. He collected many new species in this area.
Vegetative parts: plants tufted (With relatively few, tall culms), 0.5-2 m tall, basal diameter 0.05-0.1 m, crown diameter 0.1-0.5 m, compact, without spreading rhizomes or stolons. Fertile culms branching, smooth, olivaceous, 1-2 m tall, diameter at base 1.5-3.5 mm, diameter at apex 0.5-1.2 mm. Sheaths loosely convoluted or flat and standing free from culm, 10-30 mm long, brown, speckled, with the apical part eventually decaying, apical margins coriaceous, like the rest of the body, hyaline shoulders absent, apex, excluding the membranous lobes, acute. Sheath-mucro absent or penicellate or awl- or needleshaped, straight and erect, 0-3 mm long, the margins and apical part of the sheath are thinner-textured than the body, and these will eventually decay. Males: male inflorescence with 2-5 spikelets or 6-10 spikelets or 11-20 spikelets, paniculate (forming a rather dense, obconical inflorescence), 25-60 mm long, 15-30 mm wide. Male inflorescence spathes persistent, shorter than spikelets, chartaceous or cartilaginous (with the apical portions eventually decaying). Male flowers in spikelets. Male spikelets erect on stiff pedicels or sessile, linear or oblong, apex acute (when in bud) or rounded (when fully flowered), 15-25 mm, 4-5 mm, with 15-25 flowers, pedicels absent ie spikelets sessile or shorter than the spikelets, terete or angular. Male bracts taller than flowers, 3.5-4.5 mm long, oblong or ovate, acute or apiculate, cartilaginous, bract upper margin like body of bract, bract awn minute or absent, much shorter than the spikelet. Male flower 2.4-2.6 mm long. Male tepals sepals and petals the same rigidity, chartaceous, linear or oblong, inner tepals shorter than outer tepals. Male outer lateral tepals conduplicate, keel sparsely villous. Anthers 1.2-1.8 mm long, exserted from the flowers. Pistillode present. Females: female inflorescence paniculate (Distinctly obconical, and rather dense), 30-100 mm long, 10-30 mm wide, with 11-20 spikelets or 21-50 spikelets. Female spathes shorter than the spikelets or as long as the spikelets or longer than the spikelets, not obscuring spikelet, persistent, coriaceous. Female spikelet pedicel sparsely branching or pedicel much branched, oblong or elliptical, apex acute, 7-12 mm long, with 2-4 flowers, with 0-1 sterile bracts. Female bracts taller than flowers, 4-6 mm long, oblong or ovate, acute or apiculate, cartilaginous, apical margin like rest of bract, same as body of bract, awn minute or absent. Female flower 3.3-4 mm long, without a fleshy pedicel. Female tepals chartaceous, keels of lateral sepals sparsely villous, at least as tall as nut, wrapped around it and obscuring the surface, midrib flush with the tepal body, apices rounded, inner whorl longer than outer or inner whorl shorter than outer. Female outer lateral tepals conduplicate, 3-4 mm long. Female odd outer tepal oblong, 2-2.5 mm long. Female inner tepals obovate, 3-3.5 mm long. Staminodes present. Styles feathery, 3. Ovary with 1 locule, indehiscent.