38 THE NATURAL HISTORY OF BRITISH GRASSES. 
rhizome, however, occasionally renders it of value in keeping 
up river-banks; but it is oftener injurious, as spreading 
into watercourses, and thus vitiating a system of drainage 
by arresting the equable flow in the main or trunk chan- 
nels. 
tt Flowers paniculate, more or less lax. 
Agrostis—glumes of two unequal valves longer than 
the glwmel, the inner valve of which is sometimes 
absent, the outer either awned or awnless. 
Agricultural forms.—Fine bent :— 
1. A. vulgarvis—head of flowers spreading, exceedingly 
light and elegant; stolons more or less creeping, whole plant 
smooth, Hab., upland meadows and pastures.—P. 
2. A. vulgaris var. alba—imarsh-bent—head of flowers 
larger and more compact; culms rooting at the lower nodes, 
and sending out stolons ; whole plant more or less rough, 
and stouter than the preceding. Hab., ditches and wet 
places.—P. 
3. A. vulgaris, var. stolonifera —agrarian bent—head of 
flowers much congested; stolons above, rhizomes creeping 
below, the ground. Hab., stony places; mostly an accom- 
paniment of agrarian conditions,—P. 
These three forms are proved to belong to the same 
species, as from cultivation we have obtained the following 
results :— 
A plot of A. vulgaris, sown in 1855, presents the usual 
delicate form of this grass, with a tolerable admixture of 
both stolonifera and alba. 
A plot of A. stolonifera. The general plant is A. vulgaris, 
having a few stolonifera intermixed, which latter present 
more of the true alba form than the congested flowers and 
stolon growth of its proper type. These experiments, 
though they tend to confirm their specific identity, by no 
means confound the different agricultural value of the three 
forms; and indeed, agriculturally, varieties themselves are 
of equal value with true species. 
