Centothecoideae

Belongs within: Poaceae.

The Centothecoideae is a smaller assemblage of grasses with uncertain support, though members may be united by the presence of an epiblast and fused styles (Grass Phylogeny Working Group 2001).

Characters (from Grass Phylogeny Working Group 2001): Plants annual or perennial (rhizomatous or stoloniferous), herbaceous or reedlike, of warm temperate woodlands and tropical forests. Culms solid or hollow. Leaves distichous; abaxial ligule absent or present as a line of hairs (Calderonella, Thysanolaena); adaxial ligule membranous or ciliate, or membranous with ciliate margins; blades relatively broad to narrow, often pseudopetiolate, venation parallel; sheaths sometimes auriculate. Inflorescences racemose or paniculate, bracts outside of the spikelets absent. Spikelets bisexual or unisexual, (1 to)2- to many-flowered with reduction either above or below the fertile florets, often compressed laterally; lemma lacking uncinate macrohairs, if awned, the awn single; palea usually well developed, sometimes relatively short; lodicules 2 or absent, ± cuneate, many-nerved or less commonly not or scarcely vascularized; stamens (1 to)2 or 3; ovary glabrous, apical appendage absent, haustorial synergids presumed absent, styles 2, free or fused, close, stigmas 2. Caryopsis with the hilum basal, punctiform; endosperm hard, without lipid, containing simple or compound starch grains; embryo small or large, the epiblast present, scutellar cleft present, mesocotyl internode present, embryonic leaf margins overlapping. Basic chromosome number: x = 12 (x = 11 or 12? in Thysanolaena). Foliar anatomy. Mesophyll nonradiate, often with an adaxial palisade layer, fusoid-like cells frequently present as extensions of the outer parenchyma bundle sheath, arm cells absent; Kranz anatomy absent; midrib simple; adaxial bulliform cells large. Foliar micromorphology. Stomata with dome-shaped and/or triangular subsidiary cells; bicellular microhairs present, panicoid-type; papillae absent. Photosynthetic pathway. C₃.

<==Centothecoideae [Centostecoideae]
    |  i. s.: Centotheca [Centotheceae]GPWG01
    |           `--C. lappaceaGPWG01
    |                |--C. l. var. lappaceaB78
    |                `--C. l. var. bifloraB78
    |         Cyperochloa Lazarides & Watson 1987GPWG01
    |         CalderonellaGPWG01
    |         SpartochloaGPWG01
    |--ChasmanthiumGPWG01
    |    |--C. latifoliumGPWG01
    |    `--C. laxumGPWG01
    `--+--Thysanolaena [Thysanolaeneae]GPWG01
       |    `--T. maximaGPWG01
       `--ZeugitesGPWG01
            |--Z. americanaJ87
            |    |--Z. a. var. americanaJ87
            |    `--Z. a. var. haitiensisJ87
            `--Z. pittieriGPWG01

*Type species of generic name indicated

References

[B78] Bentham, G. 1878. Flora Australiensis: A description of the plants of the Australian Territory vol. 7. Roxburghiaceae to Filices. L. Reeve & Co.: London.

[GPWG01] Grass Phylogeny Working Group. 2001. Phylogeny and subfamilial classification of the grasses (Poaceae). Annals of the Missouri Botanical Garden 88 (3): 373–457.

[J87] Judd, W. S. 1987. Floristic study of Morne La Visite and Pic Macaya National Parks, Haiti. Bulletin of the Florida State Museum—Biological Sciences 32 (1): 1–136.