218 IIORTUS GRAMINEUS WOBURNENSIS. 



TRIFOLIUM medium. Marl Clover, Cow-grass. 



Specific character : Spikes loose, stems flexuose, branched ; 

 corollas nearly equal ; stipules sublate, linear. E. Bot. t. 190 ; 

 Wither. Arr. 



Obs. — The common broad-leaved red clover is distinguished 

 from the present plant by the spike, which is loose and rather 

 oblong, while that of the broad-leaved clover is globular and 

 compact. The root of the marl-grass is creeping, that of the 

 broad-leaved clover spindle-shaped and fibrous. The stem 

 of the perennial sort is more constantly zig-zag. The leaves 

 are also smoother and longer. There are three varieties of 

 the broad-leaved clover {Tri/'olium pratense), mentioned by 

 botanical writers, one of which is said to be perennial and the 

 true marl or cow-grass ; but all the seeds and plants I have 

 had for this (except that from Messrs. Gibbs and Co., which 

 proved to be the present plant) have turned out only two-year- 

 lived plants, or never exceeding three, though cultivated on 

 various soils. Since the above remarks were first printed, I 

 have found the true Trifoliutn pratense pererine in the rich 

 grazing lands in the vale of Aylesbury, and also in the rich 

 grazing lands in Lincolnshire — a figure of which is presented 

 to the reader in the following pages. The plants of marl 

 clover upon which the following experiments were made, 

 were taken from a rich ancient pasture, which was so closely 

 cropped at the time, that the plant was only three inches 

 high, though in flower. This plant is also frequent on cold 

 tenacious clayey soils, where it is of smaller stature, more 

 woody, and darker coloured ; but when transplanted to a 

 richer soil its appearance is nmch altered. The distinctions 

 of the perennial and the biennial root are the most certain, 

 and of the most importance to the Agriculturist in choosing 

 between two plants of nearly equal value for the purpose of 

 permanent pasture. To avoid any chance of mistake, there- 

 fore, I here present a figure of the marl clover or cow-grass, 

 which I have brought from a rich ancient pasture that had 

 never been under the plough, according to the oldest recol- 

 lection. 



Experiments. — At the time of flowering, the produce from a rich 

 black loam is — 



