32 THE SEEDS OF THE BLUEGRASSES. 
WEED SEEDS COMMONLY FOUND WITH COMMERCIAL BLUE- 
GRASS SEEDS. 
The following weed seeds are those most frequently found with the 
various kinds of bluegrass seed. 
Bursa bursa-pastoris (L.) Britton. 
SHEPHERD’S-PURSE. 
Seeds 3-1 mm. long, oval-oblong, one extremity often pointed by the whitish tissue 
of the scar, flattened with rounded edges; faces similar and usually presenting two shal- 
low grooves; color yellowish or reddish brown, 
usually darker near the scar; surface nearly 
smooth; endosperm absent; embryo curved 
upon itself, the cotyledons incumbent; seeds 
Cc developing a coat of transparent mucilage 
when placed in water. (Fig. 16.) 
Seldom found abundantly, but occurring 
frequently in all of the commercial bluegrass 
Fig. 16.—Seeds of shepherd’s-purse (Bursa 
bursa-pastoris): a, side view; b, edge view; 
c, Natural size of seeds. seeds. 
Lepidium virginicum L. 
PEPPERGRASS. 
Seeds 14 mm. long, much flattened, ovate with one edge straight and thicker than 
the other, the curved edge narrowly margined, the mar- 
gin usually hyaline and broadest at the broad end of the eons 
seed; faces similar, each nearly crossed lengthwise by a Ree 
curved groove; scar at the small extremity, marked by eee 
a small, whitish tissue; surface smooth, dull, and red- Cig 
dish yellow; endosperm wanting; embryo curved upon eee 
itself, the cotyledons accumbent; seeds developing a i 
copious coat of transparent mucilage when placed in view; b, edge view; ¢, natural 
water. (Fig. 17.) size of seeds. 
Frequently found in home-grown seed and sometimes very abundant, especially in 
poorly cleaned seed. 
Cerastium vulgatum L. 
MOUSE-EAR CHICKWEED. 
Seeds about 4 mm. long, flattened but not thin, rounded or triangular, the broad 
edge rounded, the narrow edge notched; surface roughened by small tubercles 
or very short ridges, dull, and reddish- 
0, @ brown; embryo cylindrical, curved about 
o ee the endosperm, its extremities nearly 
5 meeting at the notch in the seed coat. 
(Fig. 18.) 
Fig. 18.—Seeds of mouse-ear chickweed (Ce- Found irequently; sometimes abundant in 
rastium vulgatum): a, side views; 6, natural poorly cleaned seed. 
size of seeds. 
Alsine media L. 
COMMON CHICKWEED. 
Seeds circular-ovate, about 1 mm. in diameter with little variation in size, flattened 
with plane faces and flattened edges; scar in a small notch in the edge; surface dull, 
slightly tubercled, the tubercles in rows on the edges and in more or less evidently 
