A SEED KEY TO COMMON WEEDS 371 



4. Fruit white and almost globular 



Rhus Toxicodendron L. 53 



4. Not white or globular. 



5. Wafer-like usually with 2 short projections on the 

 margin, often with a narrow wing. 

 6. Style bent towards hilum, usually quite dark.... 



Laportea canadensis (L.) Gaud. 12 



6. Style straight or bent away from hilum 



Ranunculus acris L. 37 



5. Not wafer-like. 



6. Shining whitish, noticeably obliquely truncate at 



base, pappus quite persistent (fig. XXXI) 



Centaurea Cyanus L. 106 



6. Not shining white. 



7. With longitudinal striations noticeable to eye. 

 8. With numerous terminal appendages, top- 

 shaped Ambrosia artemisiifolia L. 87 



8. Without numerous terminal appendages. 

 9. Plano-convex or concavo-convex, striations 

 prominent and often spiny, greenish 



brown (fig. XXX) Baucus Carota L. 61 



9. Not as above. 

 10. Light colored. 

 11. Plano-convex tapering almost equally 



at each end 



Echinocliloa Crus-galli L. Beauv. 3 



11. Tapering unequally at the ends, not 

 plano-convex. 

 12. Surface pitted, short and thick, 

 hilum dark, apex long alternate, 



hard (fig. X) 



Lithospermum arvense L. 67 



12. Surface not pitted, not short and 

 thick, apex not long alternate (fig. 

 XIX) .Cirsium lanceolatum L. Hill 104 

 10. Dark colored. 

 11. With four or five marked striations, 



not mottled, oval, reddish 



Impatiens biflora Walt. 54 



11. Usually mottled without marked stria- 

 tions. 

 12. Angular and mottled in transverse 



lines (fig. IV) . .Arctium minus L. 103 

 12. Not angular and if mottled, mottled 



longitudinally 



Helianthus divaricatus L. 92 



7. Without noticeable longitudinal striations. 

 8. Plano-convex, not turbinate or kidney-shaped. 



