440 
Clover-Seed and its Impurities. 
Fig. 9. Papaver 
Mhmas, Linn. 
Poppy. 
Fig. 10. TMaspi arvense, Lion. 
Penny Cress. 
pletely destroyed by it. The field, in places where the parasite 
occurred, was left almost bare of vegetation. 
In further considering the impurities in samples of clover 
seed, it will be seen that they do not belong to a large number 
of families ; and as the seeds of each family agree generally in 
form and other characters, it will be better to consider them in 
their systematic order. 
Sometimes the little beaked fruits (achenes) of the Acrid 
Buttercup (Ranunculus acris, Linn.) are met with, 
and also the small pitted seeds of the common 
field Poppy (Papaver Rhceas, Linn., Fig. 9). 
Amongst the few cruciferous plants mixed with 
clover-seed the most frequent are the seeds of 
the Penny Cress (Thlaspi arvense, Linn., Fig. 10). These 
seeds are dark, oblong, ridged, and punc- 
tate. The plant is a weed in fields, an 
annual, with a small tapering root, a 
slender stem, from one to two feet high, 
and white flowers, followed by a round, 
notched, and winged pod, containing 
about twelve seeds. 
The ovate seeds of the Pansy or Heart' s- 
ease (Viola tricolor, Linn., Fig. 11) are occasionally present in 
• samples of clover. This annual, well known in pas- 
tures and banks, has small fibrous roots. It flowers 
all the summer through, producing its seeds in tri- 
• angular capsules, the valves of which are elastic, and 
spring right back when they are ripe. 
The kidney-shaped seeds of several caryophylla- 
ceous plants are common ingredients in clover. The 
most frequent are the small, pale, yellowish brown seeds of the 
Mouse-eared Chickweed (Cerastium triviale, Link, Fig. 12). 
They are rough, with elevated points on the outer 
edges. This plant is a small 
annual with a long, slender 
branched, fibrous root. It is in 
flower from April to August, and 
produces a large number of very 
small seeds. The seeds of the 
common Chickweed (Stellaria me- 
dia, Linn., Fig. 13), are not in- 
frequent. They are dark, dull brown, and rough, with lines 
of elevated points. The root of the plant is small and some- 
what tapering. The seeds of Spurrey (Spergula arvensis, Linn., 
Fig. 14) also occur. They are small and round, but somewhat 
compressed like a doubly convex lens, smooth or tubercled, and 
Fig. 11. Viola 
tricolor, Linn. 
Pansy. 
f 
Fig. 12. Cerastium 
trivial?., Link. 
Mouse-eared 
Chickweed. 
Fig. 13. Stellaria media, 
Linn. Chickweed. 
