A SEED KEY TO COMMON WEEDS 339 



to dark brownish red. S., broadly oval and slightly flattened 

 with each end slightly pointed; very finely netted with dark 

 lines. 0., common in waste land. See Beal. Fig. 15. Intro- 

 duced from Europe. 



9. Poa pratcnsis L. June Grass, Spear Grass, Kentucky 

 Blue Grass. Length of floret 3.0 — 4.4 mm., of the seed 1.1 — 

 1.5 mm. Width of seed .4 — .8 mm. C, light brown. S., equal- 

 ly three-sided in cross section with a shallow groove on one 

 side ; surface finely hairy at the angles ; angles quite distinct ; 

 quite long and attenuate at the apex. Introduced from 

 Europe. 



9a. Poa compressa L. Canada Blue Grass. This grass very 

 closel} T resembles Poa pratensis L. and is used as an adulterant 

 of the same. According to Hillman and Brown, Bull. 84, IT. 

 S. D. A., Bureau of Plant Industry, it differs principally in that 

 the intermediate veins of the glumes are distinct in Poa praten- 

 sis L. and indistinct in Poa compressa L. 



10. Glyceria nervata (Willd) Trin. Fowl Meadow Grass, 

 Beard Grass. L. .6 — 1. mm. W. .4 — .5 mm. C, black with 

 silvery reticulations. Very broadly elliptic or spindle-shaped 

 with a short acutely tipped apex ; base with a short blunt tip ; 

 surface irregularly wrinkled. 0., common in marshy regions; 

 found in seeds of alsike clover. Introduced from Europe. 



11. Bromus secah'nus L. Chess, Cheat. L. 5.8 — 7.2 mm. 

 W. 2.2 — 2.9 mm. C, dark brown or flesh colored. S., oval, 

 at least in general outline, very deeply heart-shaped in cross 

 section or spindle-shaped with a broad very deep groove up 

 one side: ''floral glume rounded on the back and obscurely 

 seven nerved; palea with a single row of stiff hairs; club- 

 shaped rachilla distinguishes it from the cultivated grasses." 

 Hillman. 0., common in seeds of cereals and large seeded 

 grasses especially in orchard grass; sometimes found in the 

 clovers. See Beal, fig. 7. Introduced from Europe. 



12. Laportea canadensis (L) Gaud. "Wood Nettle. L. 2.8 — 

 3.8 mm. W. 2.5 — 3. mm. C, dark brown to black. S., almost 

 circular but with two short projections on the edge rather 

 near each other but diverging, pronouncedly flattened. O., 

 not a bad weed in crops but common in lowlands. Native. 



13. Rumex crispus L. Narrow-leaved or Curled Dock. L. 

 1.2 — 2.2 mm. W. .7 — 1.4 mm. C, dark brown to reddish 



