grandis (L.) = large, tall, full grown. Refers to the large growthform.
WCM Protologue Reference:
H.P.Linder, S. African J. Bot. 77: 418 (2011)
Vegetative parts: plants tufted, 2-5 m tall, basal diameter 0.3-1.5 m, crown diameter 1-3 m, with rhizomes. Rhizome spreading, unbranched or sparsely branched, culms evenly spaced, 10-20 mm in diam., culms 5-40 mm apart. Fertile culms sparingly branched or branching, round (not compressed) or compressed, distinctly hollow, smooth or finely rugulose, green or olivaceous, 2-5 m tall, diameter at base 12-20 mm, diameter at apex 1.8-3.2 mm. Clusters of sterile branches at the nodes of the fertile branches present. Sterile branches present while flowering. Sheaths closely convoluted, 10-92 mm long, brown, upper 1/3 in colour and texture similar to the lower 2/3 or abruptly different from the base, and soon decaying, apical margins coriaceous, like the rest of the body, hyaline shoulders absent, apex, excluding the membranous lobes, acuminate or acute or obtuse. Sheath-mucro penicellate, straight and erect, 4-10 mm long. Males: male inflorescence with 101-500 spikelets, paniculate, 80-500 mm long, 30-150 mm wide. Male inflorescence spathes caducous, taller than spikelets, coriaceous or cartilaginous. Male flowers in spikelets. Male spikelets erect on stiff pedicels or sessile, oblong or ovate or elliptical, apex obtuse or acute, 5-12 mm, 3-6 mm, with 15-30 flowers, pedicels shorter than the spikelets or as long as the spikelets, terete or angular or flattened. Male bracts as tall as flowers or taller than flowers, 2-3.5 mm long, ovate, obtuse or acute or acuminate, chartaceous or cartilaginous, bract upper margin membranous, thinner texture than the body, bract awn minute or absent or less than half as long as the bract body, copper-coloured and shiny. Male flower 2-2.5 mm long. Male tepals sepals and petals the same rigidity or sepals more rigid than petals, membranous, petals membranous, oblong (elliptical), inner and outer tepals the same length. Male outer lateral tepals conduplicate, glabrous. Anthers 1-2 mm long, exserted from the flowers. Females: female inflorescence with 1 spikelet. Female spathes shorter than the spikelets, persistent, bony or coriaceous. Female spathellae inconspicuous or absent. Female spikelet sessile, oblong or elliptical or ovate, apex acute, 15-40 mm long, with 1-2 flowers, with 6-12 sterile bracts. Female bracts taller than flowers, 10-28 mm long, oblong or ovate, acute or acuminate, bony or coriaceous, apical margin membranous, same as body of bract, awn minute or absent or less than half as long as the bract body. Female flower with a fleshy pedicel. Female tepals membranous, glabrous and smooth, at least as tall as nut, wrapped around it and obscuring the surface or smaller than nut and not obscuring the nut surface, midrib flush with the tepal body, apices rounded, inner and outer whorls the same length. Female outer lateral tepals like other tepals, 9.8-15.3 mm long. Female odd outer tepal oblong, 9.8-15.3 mm long. Female inner tepals oblong, 9.8-15.3 mm long. Staminodes absent. Styles plumose, white, 2. Style bases free. Ovary with 1 locule, indehiscent. Fruit: indehiscent fruits with a hard woody ovary wall. Perianth presence on fruits persistent, membranous, as tall as nuts. Nut apex smooth, without a distinct cap, wall smooth, 11-16 mm long, 7-9 mm diam., shape in side view elliptical or obovate, shape in top view planoconvex in cross section, black. Elaiosome present, white, 0.2-1.1 mm long, less than half as long as nut.