This and _A. vulgaris_, With. with shorter ligules, and, possibly, _A. canina_, L. with finer leaves, are varieties of _A. alba_, L. Only the variety _A. stolonifera_ is of moderate value for pasture, especially on poor soils, as it lasts late into autumn: the others are weeds, like couch-grass. _Agrostis_ is full of difficulties for the beginner. The weed-forms often spring up after wheat has been cut, and count as “twitch,” like _Agropyrum_. All the ordinary forms--_A. stolonifera_, _A. vulgaris_, and _A. canina_--may be included in _A. alba_ (Linn.). On dry hills a close tufted grass, with setaceous leaves, and in rich soils creeping and luxuriant with broad leaves. It is one of the few grasses that thrive in wet soils. The chief points in the flat-leafed forms are the thin, dry leaves, rough on both sides and on the margins, with distinct raised ridges, and the base of the leaf narrowing suddenly into its insertion with the sheath, with no auricle, but with a long membranous ligule. The sheath not coloured, and the blade convolute. Again, _A. stolonifera_ has a long, serrated, acute ligule, while _A. vulgaris_ has a much shorter, entire and truncate one, and narrower leaves. _Agropyrum_ is the grass most likely to lead to confusion. Its ears, lower ridges, very short or obsolete ligule, and pubescence (sometimes glabrous) distinguish it. _Cynosurus_ sometimes gives trouble (see p. 50) with _Alopecurus pratensis_: the sheaths, ligule and flattened ridges should suffice for distinction. _Alopecurus geniculatus_ is even more like _Agrostis_, but its ridges are more prominent and sharp, and its aquatic habit and bent “knees” distinguish it. _Alopecurus agrestis_, in dry corn-fields, has a thickened ligule, sometimes coloured, and is annual or biennial, but otherwise very like _Agrostis_. _Alopecurus pratensis_, L. (Meadow Foxtail). Large grass with stolons; very early, and much prized as pasture and hay, but soon dies out on light poor soils. Especially good for stiff soils. Sheaths long, ridged, brown or nearly black at the base as they age. Ligule distinct and obtuse, entire. Leaves numerous. Blades long, dark green, succulent and scabrous: ridges numerous and flat above, but distinct (Fig. 9). _A. agrestis_, L. in S. England has shorter leaves, and ridges not flattened; it is a troublesome pest of arable land, but does not usually invade pasture. _A. geniculatus_, L. is semi-aquatic, and like the last. It is easily recognised by its sharply bent “knees,” and is of little value (Fig. 3). _Alopecurus_ shows resemblances to _Lolium_ (see p. 49), _Festuca_ (see p. 50), and _Agrostis_ (see p. 52). If well grown its ridged sheath and leaves, the former brown or black at the base, aid in distinguishing it. (2) Blades either devoid of ridges or with very inconspicuous ones.