The grass genera of the world
Habit, vegetative morphology. Sympodial, juncoid perennial; caespitose (the first internode of the primary culm disproportionately elongate, the upper nodes condensed). The flowering culms leafless (but after burning, small secondary culms arise by tillering from the stumps). Culms woody and persistent; unbranched above. Culm leaf sheaths absent. Culm internodes hollow (but partitioned by numerous thin septa of pith). Pluricaespitose. Rhizomes pachymorph. Plants unarmed. Leaves auriculate (the auricles weakly developed), or non-auriculate; without auricular setae. Leaf blades lanceolate (acuminate); broad; about 10 mm wide; pseudopetiolate; cross veined; disarticulating from the sheaths; rolled in bud.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence determinate; falsely paniculate (to 1 m long, never terminal to a culm); open (effusely branched, the main axis often trigonous); spatheate (with bracts and prophylls); a complex of partial inflorescences and intervening foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; not in distinct long-and-short combinations.
Female-fertile spikelets. Spikelets to 24 mm long (maximum); lanceolate; compressed laterally to not noticeably compressed; disarticulating above the glumes; disarticulating between the florets; with a distinctly elongated rachilla internode above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret; hairless. Hairy callus absent.
Glumes two; very unequal; shorter than the adjacent lemmas; hairless; glabrous; awnless (somewhat apiculate); non-carinate; similar. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets, or both distal and proximal to the female-fertile florets. The distal incomplete florets merely underdeveloped. The proximal incomplete florets 0, or 1; male, or sterile. The proximal lemmas awnless; exceeded by the female-fertile lemmas; similar in texture to the female-fertile lemmas.
Female-fertile florets (1–)2, or 3. Lemmas not becoming indurated; entire; pointed, or blunt; awnless, or mucronate (?); hairless; glabrous; non-carinate. Palea present; relatively long; not convolute; apically notched; awnless, without apical setae; 2-keeled (dorsally sulcate, the keels ciliate). Lodicules present; 3; free; membranous; glabrous; not toothed; heavily vascularized. Stamens 3. Anthers not penicillate; without an apically prolonged connective. Ovary apically glabrous; without a conspicuous apical appendage. Styles fused. Stigmas 2.
Transverse section of leaf blade, physiology. Mesophyll without fusoids.
Special diagnostic feature. Rush-like, with reduced leaf blades (but the juncoid primary culms sprouting typical bamboo twigs from their bases after burning).
Classification. Watson & Dallwitz (1994): Bambusoideae; Bambusodae; Bambuseae. Soreng et al. (2015): Bambusoideae; Bambusodae; Bambuseae; Arthrostylidiinae. 1 species (G. mirabile).
Distribution, phytogeography, ecology. Brazil.
Special comments. Fruit data wanting. Anatomical data wanting. Illustrations. • G. mirabile: McClure, New World Bamboos (1973). • G. mirabile: Camus,1913 (with Microcalamus, a panicoid grass). • Abbreviations for Camus (1913) figures
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classifications. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., Macfarlane, T.D., and Dallwitz, M.J. 1992 onwards. The grass genera of the world: descriptions, illustrations, identification, and information retrieval; including synonyms, morphology, anatomy, physiology, phytochemistry, cytology, classification, pathogens, world and local distribution, and references. Version: 11th December 2017. delta-intkey.com/grass’.