116 HOW TO GROW GOOD CLOVER. 



principal of these will be discussed in another chap- 

 ter : we may here, then, for the present leave this 

 difficult subject of how to distinguish cow-grass and 

 broad-leaved or red clover, with the observation that 

 the common red clover is uniformly in flower two or 

 three weeks before the other. 



2. Trifolium medium (see Plate) — Zigzag Trefoil 

 — gets its English name from the peculiar bends in its 

 stem, which being at alternate sides, make up the zig- 

 zag outline. The stems are rounded — not channelled, 

 — mostly of a purple colour, and clothed with short 

 hairs. The leaves are smooth, with elliptical — not 

 emarginate — leaflets, sometimes, but seldom, with the 

 white lunulate spot. The calyx is smooth. The 

 heads of flowers are solitary, on very short footstalks ; 

 they are of a bright pinkish red hue, and not of the 

 lilac colour of the common clover. 



In its wild state the zigzag clover will be found in 

 districts remarkable for the absence of lime, such as 

 the sandstones. In the sandy deposits accompanying 

 the coal in Wales, as also in Staffordshire, this is the 

 prevailing form of clover. Hence, then, this species 

 seemed to recommend itself for sandy lands, in which 

 the common clover does not so well succeed ; and we 

 conceive that, as a consequence, it was brought into 

 cultivation for this capability of " holding on " to such 

 soils, which, if they will not grow the other kind, is 

 considered clover sick. We have reason to think that 

 the T. medium and T. pratense are not distinct 

 species, but that the difference in their usual 

 habitats has determined their difference in form, 

 and we think that the T. pratense perenne of tbe 

 seedsman is a form intermediate between the two : 



