34 



THE SEEDS OF THE BLUEGRASSE8. 



in the more expensive kinds of bluegrass seed indicates the probable use of Canada 

 bluegrass seed as an adulterant. These prickles have been found, however, in rough- 

 stalked meadow grass seed in which no trace of Canada bluegrass seed appeared. 

 Owing to the troublesome nature of Canada thistle, care should be taken not to 

 introduce its seeds with those of the bluegrasses. 



Taraxacum taraxacum (L. ) Karst. 



DANDELION. 



Seeds (akenes) 3-4 mm. long, including the per- 

 sistent base of the beak, which forms the pointed 

 apex of the seed, lance -shaped or broadly so, 

 straight or curved, flattened or slightly four- 

 angled with similar faces, barbed in the upper, 

 broader half; teeth directed toward the apex, 

 prominent on the edges and arranged in about 

 five rows on each face, which has two slender 

 grooves with three rows of teeth between them; surface dull; color light brown or 

 dark brown. (Fig. 22.) 



Occurring occasionally in both American and European seed, these seeds have 

 appeared most frequently in Kentucky bluegrass and rough-stalked meadow grass 

 seeds. 



Matricaria inodora L. 



Fig. 22.— Seeds of dandelion ( Taraxa 

 cum taraxacum): a, side views; b, nat 

 ural size of seeds. 



SCENTLESS CAMOMILE. 



% 

 ^ 



H 



h 



Seeds (akenes) 1^-2 mm. long, slender or 

 robust, oblong with obtuse extremities, taper- 

 ing somewhat from the truncate apex to the 

 base, slightly flattened; faces dissimilar, one 

 having three prominent, longitudinal ribs 

 joined at the apex, the lateral ribs and a partial 

 one joined to them at the apex appearing on 

 the opposite face, which also presents two small cavities separated by the partial 

 ridge; surface between the ridges transversely roughened, dark brown or black and 

 darker than the brown or yellowish ridges. (Fig. 23. ) 



Found only in foreign-grown seed, chiefly in rough- 

 stalked meadow grass and wood meadow grass seeds. 



Fig. 23.— Seeds of sfentless camomile 

 {Matricaria inodora): a, back, front, and 

 edge views; b, natural size of seeds. 



F 



1 



Hieracium sp. 



HAWKWEED. 



Seeds (akenes) 1-3 mm. long, cylindrical, pointed at 

 the base; apex truncate, bearing a small tuft of short, 

 whitish, marginal bristles (the remnants of the pappus 

 bristles); surface lightly ten-ridged lengthwise; color 

 brown or black, reddish in immature seeds. (Fig. 24. ) 

 Found most frequently in wood meadow grass seed. 

 The seeds of several species of hawkweed, occurring in both America and Europe, 

 are practically indistinguishable. Specific determinations can not be made by exam- 

 ination with a lens. The troublesome character of rrrange hawkweed {Hieracium 

 aurantiacum), whose seeds are IJ-lf mm. long, justifies care in the use of seed 

 containing seeds of any species of hawkweed. 



Fig. 24. — Seeds of hawkweed 

 {Hieraciumsp.): a, side views; 

 b, natural size of seeds. 



