Family: Poaceae |
Plants annual or perennial (rhizomatous, stoloniferous, cespitose, or decumbent), primarily herbaceous, sometimes reed-like, polygamous or monecious or dioecious. Culm intemodes usually solid, less commonly hollow. Leaves distichous; sheaths usually nonauriculate; abaxial ligules usually absent, occasionally present as a line of hairs; adaxial ligules a fringed or unfringed membrane or a fringe of hairs, rarely absent; blades broadly ovate to narrow and linear, sometimes pseudopetiolate, sometimes tessellate. Inflorescences paniculate, racemose or spicate, or complex combinations of these, sometimes bracts present outside the spikelets present (Andropogoneae). Spikelets bisexual or unisexual (if unisexual, plants unisexual or bisexual), solitary or often paired or in triads, usually dorsally compresed with glumes 2, sterile lemma 1 and female fertile floret 1 and dorsally compressed or laterally compressedn with glumes 2 and ( 1-) 2 to many female fertile florets with reduction either above or below the fertile florets; disarticulation below the glumes, above the glumes in Arundinelleae and Tristachyideae, above the glumes and between the florets, or the inflorescence axes breaking apart; lemmas indurate or membranous, lacking uncinate macrohairs, if awned, the awns usually single; paleas well developed or reduced to absent; lodicules 2 or sometimes absent, cuneate,free, fleshy; stamens (1 or 2) 3; ovaries usually glabrous, apical appendage absent, haustorial synergids absent; styles usually 2, usually free, or rarely fused; stigmas 2 (rarely 1 or 3). Caryopses with the hilum basal and punctate or sometimes linear; endosperm hard, without lipids, usually with simple or, less commonly, compound starch grains; embryos usually large, sometimes small, formula P-PP but sometimes P+PP (mesocotyl elongated, epiblast absent or sometimes present, scutellar cleft present, margins of the first leaf overlapping). Basic chromosome numbers x = 5, (7), 9, 10, 12, (14). Foliar micromorphology-Stomata with triangular or dome-shaped subsidiary cells; bicellular microhairs present, panicoid-type, rarely absent; papillae absent or present (mostly present in Andropogoneae). Photosynthetic pathway-C3, C4 (PCK, NAD-ME, and NADP-ME), and some C/C4 intermediates. The Panicoideae includes nearly 220 genera and approximately 3300 species. It is distributed virtually worldwide but has its highest diversity in tropical and subtropical regions.
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