376 IOWA ACADEMY OF SCIENCE 



9. Broadest toward base, turbinate, base very 



dark (fig. X) . . . . Lithospermum arvensc L. 67 

 6. Not pointed at either end. 

 7. With longitudinal striations or sharp angles. 



8. Dark brick-red Oenothera biennis L. 59 



8. Not dark brick-red. 



9. Plano-convex or concavo-convex, greenish 



brown (fig. XXX) Daucus Carota L. 61 



9. Not plano-convex or concavo-convex, light 

 straw-colored, blunt at the ends (fig. 



XXVI) Anthemis arvensis L. 98 



7. Without longitudinal striations. 

 8. Flattened or concave on two sides. 



9. Covered with short hairs (fruit) 



Malva moschata L. 57 



9. Not covered with short hairs. 



10. With a narrow wing, almost round, thin 



at edges Ranunculus abortivus L. 36 



10. Without a narrow wing, thick at one 

 edge, thinner at the other. 

 11. No angles, edges rounded, faces con- 

 cave with outer coat on 



Malva moschata L. 57 



11. Faces plane with outer coat on, darker 

 than next preceding. .Malva rotundifolia L. 56 

 8. Not flattened or concave, faces slightly convex. 

 9. With a short distinct elevation near scar 

 reaching beyond the normal outline of the 

 seed (fig. XXXIII) . . .Medicago lupulina L. 51 

 9. Without. a short distinct elevation at scar 

 extending beyond normal outline of seed. 

 10. Kidney shaped or angular usually with 

 deep concavity near scar (fig. XXXII) 



Medicago sativa L. 50 



10. Almost uniformly oval. 

 11. Usually over 2 mm. long, notch near 



one end Melilotus alba Desr. 49 



11. Usually under 2 mm. long, notch near 



the center of one side 



Trifolium pratense L. 46 



I. 1 to 2 mm. long. 



II. At least twice as long as broad. 

 1. Black or nearly so. 



2. Rounded alike at both ends, bisymmetric when cut trans- 

 versely; surface appearing granular but composed of 



rectangular markings Hypericum perforatum L. 58 



2. Not rounded at both ends or bisymmetric when cut trans- 

 versely. 

 3. Quite pronouncedly square in cross section. 



