36 



THE SEEDS OF THE BLUEGKASSES. 



Rumex crispus L. 



CURLED DOCK. 



Seeds (akenes) I5-2I mm. long, triangular with equal faces and broadly ovate- 

 lanceolate; color dark reddish brown; surface smooth, polished; apex acute; base 

 obtuse, contracted, and narrowly truncate at the scar; edges narrowly margined; 



faces longitudinally concave in poorly developed 

 seeds; true seed coat thin; embryo cylindrical, rest- 

 ing in the center of one face of the endosperm; 

 caulicle pointing to the base of the akene. (Fig. 28. ) 

 Found occasionally, especially in Kentucky blue- 

 grass and in Canada bluegrass seeds; small, imper- 

 fectly developed seed more commonly found than 

 large, heavy seed. Their sharply three-angled, 

 beechnut-like form distinguishes them from other 

 impurities, except one or two other kinds of dock. The docks are destructive weeds, 

 and care should be taken to prevent the sowing of their seeds. 



Rumex acetosella L. 

 sheep's sorrel, sorrel. 





Fig. 28.— Seeds of curled dock (Kh- 

 mex crispus): a. broad and narrow 

 forms; h, natural .size of seeds. 



Fig. 29.— Seeds of sorrel (Rumex acetosella): a, b, and c, 

 seed enveloped by the perianth; d, seed with perianth 

 removed; e, natural size of seeds. 



Seeds (fruits) acutely oval, three-angled, with equal faces, 1-lj mm. long; repre- 

 sented in commercial seed by the seed-like akene only or by the akene covered by 

 the thin, closely fitting perianth segments, which are six in number, three broad 

 ones covering the sides of the 



akene and three small ones cover- ^^^ v^Jk /^fe. .^tk. • 



ing the angles at the base; covered 

 by the perianth, the seeds are 

 finely roughened, dull, and red- 

 dish brown ; venation of the three 

 broad segments evident; small 

 segments at the basal angles often 

 broken away; akenes but slightly 

 smaller than when covered by the perianth, bluntly three-angled; surface smooth, 

 somewhat polished, reddish brown or wine colored, often semitranslucent; angles 

 dark at the apex; internal structure essentially the same as in Mnmex crispus. 



(Fig. 29.) 



One of the commonest impurities in commercial 

 seed, found in all seed of the cultivated bluegrasses. 



Veronica arvensis L. 



CORN SPEEDWELL. 



Seeds 5-f mm. long, flattened and thin, more or 

 less regularly oval, jjlane or sometimes curved face- 

 wise; center of the inner face marked by the relatively 

 large, raised chalaza, which is united by a narrow 

 ridge (the raphe) to the scar on the edge of the 

 smaller extremity of the seed; external face slightly ridged longitudinally, indicat- 

 ing the position of the embryo, which is surrounded by the endosperm; surface dull, 

 finely roughened by somewhat radially-disposed ridges, and reddish yellow. (Fig. 

 30.) 



Fig. 30. — Seeds of corn speedwell 

 ( Veronica arvensis): a and 6, front 

 views, c, back view; d, natural 

 size of seeds. 



