438 
Clover-Seed and its Impurities. 
Fig. 5. Uedicago lupulina, Linn. 
Black Medick. 
its value. Thus it is very rare to procure one variety of culti- 
vated clover without a certain admixture of one or more, and 
perhaps all, of the other cultivated species. The seeds of 
white clover are most frequently met with in other clover-seeds 
and in the largest quantity. But it is obviously a difficult 
matter to keep a field free from all but one species or variety, 
though careful seed-growers should en- 
deavour to secure this. 
Besides the seeds of other clovers, 
the seeds and sometimes the small black 
reticulated and single-seeded pods of 
Medicago lupulina, Linn., Black Me- 
dick, or Black Grass (Fig. 5), are found 
mixed with clover. This is a native 
British plant common in fields and 
waste places. It has a tapering fibrous 
root, a much-branched stem, clover-like 
leaves, and small yellow flowers in ovoid 
heads. It is an annual plant which 
flowers and fruits freely throughout the summer months. 
Along with the clovers, as a harmless ingredient in some 
samples, may be placed the small oval seeds of 
Phleum pratense, Linn., or Timothy-grass (Fig. 6), 
which is a well-known excellent fodder-grass, an 
ingredient in all good permanent pasture. 
The two weeds which are justly most dreaded 
by agriculturists are the two parasites which live 
on the vital juices of the clover. The one, the 
Dodder, pushes its suckers into the stems of the plant; 
while the other, the Broom-rape, attacks the root, and there obtains 
its prepared food. The Dodder ( Cuscuta Trifolii, Bab.) (Fig. 7) 
is an annual plant, flowering in July and August. 
In germinating it pushes its small root-fibre into 
'wP "°° the soil, and sends up its wiry, leafless stem to lay 
hold of the clover. As soon as it has secured 
connection with the foster plant it withdraws from 
its connection with the ground, and maintains its 
whole life at the expense of the clover. Its slender reddish 
stem grows with wonderful rapidity, and often forms, at the 
expense of the clover, immense masses like small hay-cocks. 
The small white or pinkish flowers are produced in spherical 
heads at intervals along the stem. Its two seeds are con- 
tained in a small, roundish capsule. The seeds are small and 
flat, and of a pale-brown colour. They are so small that a 
careful sifting of the clover-seed easily separates them com- 
pletely, so that there is no excuse for their presence in any 
Fig 6. Phleum, 
pratense, Linn. 
Timothy-grass. 
Fig. 1. Cuscuta 
Trifolii, Bab. 
Dodder. 
