64S 



WEED FLORA OP IOWA 



Fig. 421. Microscopic structures of seeds of some leguminous weeds. 

 I. and V. Yellow Sweet Clover (MeZiJottts officinalis). II. White Sweet 



Clover (Melilotus alba). III. Blaclt Medick (.Medicaffo liipulviia). IV. 



Bur Clover (Medicago dentioulata). 

 m=malplghlan cells. ll=light line of the same. o=osteosclerid. em=embryo 



t=testa. en=endosperm. p^parencliyma. n=nucellus. 

 (Drawings by L. H. Pammel.) 



