382 IOWA ACADEMY OF SCIENCE 



7. Equally flattened or convex, margin rounded, 

 no groove but a slight notch present (fig. VII) 

 Chenopodium hybridum L. 21 



6. Calyx not markedly persistent, seeds strongly con- 



vex on both faces. 

 7. Seeds almost perfectly round in outline, rarely 



over 1.2 mm. long. . . . Amaranthus graecizans L. 26 

 7. Seeds not perfectly round in outline, broadly 

 ovate. 

 8. Angle at margin very marked, usually larger 



than next following species 



Amaranthus hybridus L. 25 



8. Angle at margin indistinct, usually smaller 



(fig. XLI) Amaranthus retroflexus L. 24 



4. Not shining, dull. 



5. Not at all round, angles quite distinct. 



7. Surface with fine reticulations. .Plantago major L. 77 

 6. Surface granular, not reticulate 



Plantago Rugelii Dene. 78 



5. Round or nearly so. 



6. Surface covered with concentric rows of small 

 tubercle-like projections giving a granular ap- 

 pearance, somewhat kidney-shaped 



Saponaria officinalis L. 34 



6. Surface quite smooth. 



7. Broadly notched at one side, not lens-shaped.. 



Trifolium hybridum L. 48 



7. Notch slight, somewhat lens-shape. 

 8. With calyx present, lines of calyx run trans- 

 versely entirely across the seed; with calyx 

 off a "groove runs from the side to the 



notch" Atriplex patula L. 23 



8. With calyx present, lines of the calyx run 

 radially; with calyx off, a groove runs from 

 notch to center of the face of the seed .... 



Chenopodium album L. 22 



2. Not black or nearly so. 

 3. Shining surface. 



5. Over 1.8 mm. long. 



5. Pronouncedly compressed, broad oval or kidney- 

 shaped. 



6. Black Polygonum Persicaria L. 17 



6. Not black Trifolium pratense L. 46 



5. Not pronouncedly compressed. 



6. Usually with a whitish appendage at base, not 



flattened on one side (fig. XXV) 



Prunella vulgaris L. 71 



6. Flattened slightly on one side, without appendage 



Setaria viridis L. Beauv. 5 



