32 



THE SEEDS OF THE BLUEGRASSES. 



WEED SEEDS COMMONLY FOUND WITH COMMERCIAL BLTJE- 



GBASS 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 f-1 mm. long, oval-oblong, one extremity of ten pointed by the whitish tissue 

 of the scar, flattened with rounded edges; faces similar and usually presenting two shal- 

 low grooves; color yellowish orreddish brown, 

 usually darker near the scar; surface nearly 

 smooth; endosperm absent; embryo curved 

 upon itself, the cotyledons incumbent; seeds 

 developing a coat of transparent mucilage 

 when placed in water. (Fig. 16.) 



Seldom found abundantly, but occurring 

 frequently in all of the commercial bluegrasa 

 seeds. 



Fig. 16.— Seeds of shepherd's-purse (Bursa 

 bursa-pastoris): a, side view; b, edge view; 

 c, natural size of seeds. 





L 



■Seeds of peppergrass 

 (Lepidium virijinicum): a, side 

 view; b, edge view; c, natural 

 size of seeds. 



a 



Fig. 1' 



Lepidium virginicum L. 



PEPPERGRASS. 



Seeds 1 J 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 

 seed; faces similar, each nearly crossed lengthwise by a 

 curved groove; scar at the small extremity, marked by 

 a small, whitish tissue; surface smooth, dull, and red- 

 dish yellow; endosperm wanting; embryo curved upon 

 itself, the cotyledons accumbent; seeds developing a 

 copious coat of transparent mucilage when placed in 

 water. (Fig. 17.) 



Frequently found in home-grown seed and sometimes very abundant, especially in 



poorly cleaned seed. 



Cerastium vulg-atum L. 



MOUSE-EAR CHICKWEED. 



Seeds about \ 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- 

 brown; embryo cylindrical, curved about 

 the endosperm, its extremities nearly 

 meeting at the notch in ttie seed coat. 

 (Fig. 18.) 



Found frequently; sometimes abundant in 

 poorly cleaned seed. 



-TA/y. 



a 



Fig. 18. — Seeds of mouse-ear chickweed ( Ce- 

 rastium vulgatum): a, side views; b, natural 

 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 '\^ rftprei or less evidently 



