A SEED KEY TO COMMON WEEDS 375 



6. With a narrow wing and two projections, the 



style bent towards hilum 



Laportea canadensis L. Gaud. 12 



4. Not black or blackish. 



5. Margin rounded Polygonum Persicaria L. 17 



5. Margin acute Ranunculus acris L. 37 



2. Not thin and wafer-like. 

 3. Surface shining. 

 4. Flattened. 



5. Round Chenopodium hybridum L. 21 



5. Not round. 



6. Black, broadly spindle formed 



Polygonum Persicaria L. 17 



6. Not black, shield shaped. .. .Trifolium pratense L. 46 

 4. Not flattened. 

 5. With a small white appendage at base (fig. XXV) 



Prunella vulgaris L. 71 



5. Dark disk at base, turbinate. .Lithos per mum arvense 67 

 3. Surface not shining. 



4. Diameter from end to end nearly uniform, somewhat 

 4-angled. 



5. Dark brown and comparatively thick 



Verbena urticaefolium L. 68 



5. Light brown and comparatively slender 



Verbena hastata L. 69 



4. Diameter not uniform from end to end. 

 5. Black or nearly so. 



6. Covered with bristling gray hairs (fruit) 



Malva moschata L. 57 



6. Not covered with gray hairs. 

 7. More than 2.5 mm. long. .Agrostemma Githago L. 31 



7. Less than 2.5 mm. long 



Saponaria officinalis L. 34 



5. Not black or nearly so. 



6. Pointed at least at one end. 

 7. Plano-convex or concavo-convex with longitudi- 

 nal striations, oval (fig. XXX) 



Daucus Carota L. 61 



7. Not plano-convex or concavo-convex. 

 8. Distinctly red-brown. 



9. Coat closely fitting, irregularly or regu- 

 larly triangular in cross section, reddish 



brown (fig. XXX) Daucus Carota L. 61 



9. Coat loosely fitting, angles slightly winged 



Oenothera biennis L. 59 



8. Not red-brown. 



9. Broadest at apex, light straw-colored with 

 about 9 longitudinal lines (fig. XXVI).. 

 Anthemis arvensis L. 98 



