. Bulletin. 1901-13. Agriculture; Agriculture. 9 * I Seeds (akenes) 1J-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 i
. Bulletin. 1901-13. Agriculture; Agriculture. 9 * I Seeds (akenes) 1J-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 scentless camomile (Matricaria inodora): a, back, front, and edge views; b, natural size of Hieracium sp. IIAWKWKKD. 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. L»4.) 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 witli a lens. The troublesome character of orange hawkweed {Hieracium aurantiacum), whose seeds are 11 l| nun. long, justifies care in the use of seed containing seeds of any species of hawkweed. FlQ. 24.—Seed- of liawkwcrd Hieracium sp, i: a, side views; b, natural sizr of Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States. Bureau of Plant Industry, Soils, and Agricultural Engineering. Washington Govt. Print. Off
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