IOWAACATI'V )F SCIENCE 



'.-. >r::~T single ti:-:::l; :r.e 

 :;:•:- :-:"; liris ler.r:l; ::' 

 ttened and orer 1.3 

 mm. kmg 1 ; :iiiun rudt 



- r. :t longitudinal groove. 

 1. Dne end sharply poir" 



in appearance, usually with an 

 a: : : z: ; .- r. y : r. £ = i-ale 

 13. Us . - Fei 1 . mm. long, pointed 



each end P'^'.eum pratens? L - 



13. Usually under L2 mm. long, 

 pointed at one end, scar less 

 than one-fonrth length of seed 



Agrostis alba Schrad. 7 



12. Ends not sharp pointed, appearance 

 z:~ ::~.y LrT«: 



B rfaee rery finely pir.ei 

 1 - Lig I :>red, often with 



. adjacent flattened areas. . . 



Beyrich 65 



1- ■ . - :ri :- as 



'.' Erreg olarly flattened, -;me- 

 Sg. XXXIX 

 . . . .Baroarea vulgaris R. Br. 42 

 15 ■ markedly flattened, dn 



thai. U :ng. .. . 



Brassica nigra L. Koch. 40 



- -face not finely 



- race granular. 

 I r notch near the scar, 



■ : 



Cuzcuta GronovH Willd. 63 



la Light red, often with 



flatten e ; a res.-, clearly 



ma: ar.g".es 



. . . ' Beyrich 85 



14. Surface not granular, usually 

 a notch near the - 

 : " Witl a shorl -;.--..-.--. ; -! ; : 

 ::'.: - --■- r " 



rnal outline 



on the 



end, nsually 



: " | flg. 



■;:::: 



Mea'icago lupuHna L. 51 



