Plants perennial; cespitose, rhizomatous, rhizomes short, slender. Culms slender, often compressed. Sheaths usually keeled; ligules minute, membranous, often erose or ciliate; blades exhibiting Kranz anatomy, with few organelles in the external sheath and 5-7 isodiametric mesophyll cells between the vascular bundles. Inflorescences terminal, open to contracted panicles; primary branches few, slender; pedicels short, to 1 mm. Spikelets ellipsoid or lanceolate, initially somewhat compressed, ultimately expanding greatly. Glumes glabrous; lower glumes 1/3-1/2 as long as the spikelets, usually 3(5)-veined, acute; upper glumes and lower lemmas subequal, 3-5(7)-veined; lower florets sterile or staminate, often standing apart from the upper florets at maturity; lower paleas longer than the lower lemmas, greatly inflated at maturity, indurate; upper florets ovoid or ellipsoid; upper lemmas usually dull-colored, minutely papillose, papillae in longitudinal rows, apices acute. x = 9 or 10. Name from the Greek steinos, narrow, and chasma, yawning, presumably alluding to the gaping glumes and somewhat narrow spikelet when compared to Panicum (Clifford 1996).
Steinchisma is a genus of 5-6 species that grow in moist or wet, usually open, sandy areas in warm-temperate and tropical regions of the Western Hemisphere. A single species is native the Flora region. It is sometimes included in Panicum, but recent studies support its recognition as a separate genus. Photosynthesis in Steinchisma is intermediate between C3 and C4 plants.
SELECTED REFERENCESClifford, H.T.1996. Etymological Dictionary of Grasses, Version 1.0 (CD-ROM). Expert Center for Taxonomic Identification, Amsterdam, The Netherlands; Zuloaga, F.O., O. Morrone, A.S. Vega, and L.M. Giussani. 1998. Revisión y análisis cladístico de Steinchisma (Poaceae: Panicoideae: Paniceae). Ann. Missouri Bot. Gard. 85:631-656.
