The grass genera of the world
Habit, vegetative morphology. Perennial (with dimorphic culms). The flowering culms leafless. Culms 50–80 cm high. Plants unarmed. Leaves not basally aggregated; auriculate; with auricular setae. Leaf blades lanceolate, or ovate-lanceolate, or ovate; broad; 15–55 mm wide (6.5–27 cm long); pseudopetiolate; cross veined; rolled in bud. Ligule a fringed membrane (minute).
Reproductive organization. Plants monoecious with all the fertile spikelets unisexual; without hermaphrodite florets. The spikelets of sexually distinct forms on the same plant; female-only and male-only. The male and female-fertile spikelets segregated, in different parts of the same inflorescence branch (female spikelets above, male below). The spikelets overtly heteromorphic (males smaller).
Inflorescence. Inflorescence narrowly paniculate; espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-sterile spikelets. Male spikelets 2.7–4.4 mm long. The male spikelets without glumes (or these vestigial); without proximal incomplete florets; 1 floreted. Male florets 1; 2–3 staminate. The staminal filaments joined (monadelphous).
Female-fertile spikelets. Spikelets 4–9 mm long; not noticeably compressed to compressed dorsiventrally; disarticulating above the glumes. Rachilla terminated by a female-fertile floret. Hairy callus present. Callus short (minute, shortly bearded).
Glumes present; two (leathery); shorter than the adjacent lemmas (about half as long); not pointed (blunt); awnless. Lower glume 3–9 nerved. Upper glume 3–6 nerved. Spikelets with female-fertile florets only.
Female-fertile florets 1. Lemmas decidedly firmer than the glumes (leathery); not becoming indurated (or only slightly so); awned. Awns 1; median; apical; non-geniculate; about as long as the body of the lemma to much longer than the body of the lemma. Lemmas hairy (with appressed hairs); non-carinate; 5 nerved, or 7 nerved. Palea present (hairy); relatively long; convolute around the flower; awnless, without apical setae; 2-nerved. Lodicules present; 3; membranous (pointed); heavily vascularized. Stamens 0 (3 staminodes). Ovary apically glabrous. Styles fused. Stigmas 2.
Fruit, embryo and seedling. Hilum long-linear.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present; mostly intercostal. Intercostal papillae over-arching the stomata; several per cell (large, thick walled, clustered in rosettes around the stomata). Intercostal zones with typical long-cells (seemingly, the outlines obscured by papillae). Mid-intercostal long-cells having markedly sinuous walls. Microhairs present; elongated; panicoid-type. Stomata common (obscured by papillae). Subsidiaries non-papillate. Intercostal short-cells not observable. Costal short-cells conspicuously in long rows, or predominantly paired, or neither distinctly grouped into long rows nor predominantly paired (the disposition varying from place to place). Costal silica bodies absent to poorly developed (in material seen, but with panicoid type and saddle shaped silica cells).
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade; with arm cells; without fusoids. Leaf blade adaxially flat. Midrib seemingly not readily distinguishable (material seen poor). Bulliforms present in discrete, regular adaxial groups; in simple fans (these large). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming figures (in the main bundles). Sclerenchyma not all bundle-associated. The extra sclerenchyma in abaxial groups and in adaxial groups; abaxial-hypodermal, the groups isolated (opposite the bulliforms), or adaxial-hypodermal, contiguous with the bulliforms.
Classification. Watson & Dallwitz (1994): Bambusoideae; Oryzodae; Olyreae (Buergersiochloeae). Soreng et al. (2015): Bambusoideae; Bambusodae; Olyreae; Buergersiochloinae. 1 species.
Distribution, phytogeography, ecology. New Guinea.
References, etc. Morphological/taxonomic: Blake 1946; Fitjen 1975. Leaf anatomical: this project.
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: 13th November 2017. delta-intkey.com/grass’.