The sheaths are much dilated in Alopecurus vaginatus and in a species of Potamochloa, in the latter, an East Indian aquatic grass, serving as floats.
The leaves are occasionally woolly, as in Alopecurus lanatus and one or two Panicums. The blade is often twisted, frequently so much so that the upper and under faces become reversed.
Useful grasses which are increased are Lolium perenne and Alopecurus pratensis, and among those of less value Avena favescens, Dactylis glomerata and Poa pratensis.
Of those with only bisexual flowers, many are strongly protogynous (the stigmas protruding before the anthers are ripe), such as Alopecurus and Anthoxanthum (fig.
Phleum has a cylindrical spike-like inflorescence; P. pratense (timothy) is a valuable fodder grass, as also is Alopecurus pratensis (foxtail).