34 THE SEEDS OF THE BLUEGRASSES. 
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. 
2 
Taraxacum taraxacum (L.) Karst. 
DANDELION. 
% # Seeds (akenes) 3-4 mm. long, including the per- 
sistent base of the beak, which forms the pointed 
- F ge apex of the seed, lance-shaped or broadly so, 
b straight or curved, flattened or slightly four- 
angled with similar faces, barbed in the upper, 
Fic. 22.—Seeds of dandelion (Tarara- broader half; teeth directed toward the apex, 
cum taraxacum): a, side views; >, nat- prominent on the edges and arranged in about 
ural size of seeds. P 9 
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. 
SCENTLESS CAMOMILE. 
Seeds (akenes) 14-2 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 FiG. 23.—Seeds of scentless camomile 
joined at the apex, the lateral ribs and a partial eee GAM a ie a mm! 
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. 
J i Hieracium sp. 
a HAWKWEED. 
— Seeds (akenes) 1-3 mm. long, cylindrical, pointed at 
b the base; apex truncate, bearing a small tuft of short, 
whitish, marginal bristles (the remnants of the pappus 
Fic. 24.—Seeds of hawkweed bristles); surface lightly ten-ridged lengthwise; color 
(Mieraciumsp.): a, side views; brown or black, reddish in immature seeds. (Fig. 24.) 
Ummaturalisize ohsceds. 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 orange hawkweed (Hieracium 
aurantiacum), whose seeds are 14-1? mm. long, justifies care in the use of seed 
containing seeds of any species of hawkweed. 
