Poaceae subfam. Arundinoideae
Plants usually perennial; cespitose or not, sometimes rhizomatous, sometimes stoloniferous. Culms 15-1000 cm, annual, herbaceous to somewhat woody, internodes usually hollow. Leaves usually mostly cauline, often conspicuously distichous; sheaths usually open; auricles usually absent; abaxial ligules usually absent (of hairs in Hakonechloa); adaxial ligules membranous or of hairs, if membranous, often ciliate; blades without pseudopetioles, sometimes deciduous at maturity; mesophyll usually non-radiate (radiate in Amnio); adaxial palisade layer absent; fusoid cells absent; arm cells usually absent (present in Phragmites); Kranz anatomy absent; midribs simple; adaxial bulliform cells present; stomatal subsidiary cells low dome-shaped or triangular; bicellular microhairs usually present, usually with long, narrow terminal cells; papillae usually absent. Inflorescences usually terminal, ebracteate, usually paniculate, occasionally spicate or racemose. Spikelets laterally compressed, with 1-several bisexual florets or all florets unisexual and the species dioecious; florets 1-several, terete or laterally compressed, distal florets often reduced; disarticulation above the glumes. Glumes 2, from shorter than the adjacent lemmas to exceeding the distal florets; lemmas (3)5-7-veined, lanceolate to elliptic, acute to acuminate, sometimes awned; awns 1 or 3, if 3 not fused into a single basal column; paleas subequal to the lemmas; lodicules 2, usually free, occasionally joined at the base, fleshy, usually glabrous, not, scarcely, or heavily vascularized; anthers (1)2-3; ovaries glabrous; styles 2, usually free, bases close together. Caryopses usually punctate (long-linear in Molinia); endosperm hard, without lipid; starch grains compound; haustorial synergids absent; embryos usually large compared to the caryopses, waisted or not; epiblasts absent; scutellar cleft present; mesocotyl internode elongate; embryonic leaf margins usually meeting (overlapping in Hakonechloa). x = 6,9, 10, 12.
The Arundinoideae are interpreted here as including only one tribe, the Arundineae. The tribe used to be interpreted more broadly (e.g., Watson et al. 1985; Clayton and Renvoize 1986; Kellogg and Campbell 1987), but the broader interpretation was generally acknowledged to be somewhat artificial. Hsiao et al. (1998) showed support for inclusion of the Danthonieae, Aristideae, and Amndineae in a more broadly interpreted Arundinoideae, but other studies (e.g., Hilu et al. 1990; Barker et al. 1995, 1998; Grass Phylogeny Working Group 2001) have failed to support such a treatment.
Barker, N.P., H.P. Linder, and E.H. Harley. 1998. Sequences of the grass-specific insert in the chloroplast rpoC2 gene elucidate generic relationships of the Arundinoideae (Poaceae). Syst. Bot. 23:327-350
Conert, H.J. 1987. Current concepts in the systematics of the Arundinoideae. Pp. 239-250 in T.R. Soderstrom, K.W Hilu, C.S. Campbell, and M.E. Barkworth (eds.). Grass Systematics and Evolution. Smithsonian Institution Press, Washington, D.C., U.S.A. 473 pp.
Grass Phylogeny Working Group. 2000. A phylogeny of the grass family (Poaceae), as inferred from eight character sets. Pp. 3-7 in S.W.L. Jacobs and J. Everett (eds.). Grasses: Systematics and Evolution. International Symposium on Grass Systematics and Evolution (3rd:1998). CSIRO Publishing, Collingwood, Victoria, Australia. 408 pp.
Kellogg, E.A. and C.S. Campbell. 1987. Phylogenetic analyses of the Gramineae. Pp. 310-322 in T.R. Soderstrom, K.W. Hilu, C.S. Campbell and M.E. Barkworth (eds.) Grass Systematics and Evolution. Smithsonian Institution Press, Washington, D.C., U.S.A. 473 pp.