372 IOWA ACADEMY OF SCIENCE 



9. With fine transverse striations 



Setaria glauca L. Beauv. 4 



9. Surface shining without transverse stria- 

 tions Echinochloa Crus-galli L. Beauv. 3 



8. Not plano-convex. 



9. Somewhat turbinate, not at all kidney- 

 shaped, hilum dark, surface light spotted 



with dark (fig. X) 



Lithospermum arvense L. 67 



'9. Not at all turbinate, somewhat kidney- 

 shaped. 



10. Surface shallow-pitted, dark 



Datura Stramonium L. 73 



10. Surface smooth, not pitted. 



11. Usually over 3.2 mm. long, notch at 



hilum very deep (fig. XXXVIII) 



Abutilon Theophrasti Medic. 55 



11. Usually under 3.2 mm. long, notch at 



hilum not very deep 



Maiva moschata L. 57 



I. 2 to 3 mm. long. 



II. At least twice as long as broad. 



1. Appearing white or nearly so, streaked with dark gray. 



2. Flattened Achillea millefolium L. 96 



2. Not flattened (fig. XXVIII) 



Chrysanthemum Leueanthem urn L. 99 



1. Not white or gray. 

 2. Black or nearly so. 



3. Boat-shaped or aUantoid in cross section, shining 



(fig. XV) Plantago lanceolata L. 79 



3. Not boat-shaped or allantoid in cross section. 

 4. More than .6 mm. broad. 



5. Shaped like a quarter of a cylinder, very regularly 



angled, crowned with short gray hairs 



Leonurus Cardiaca L. 72 



5. Irregularly angled, surface not reticulated, angles 



distinct Plantago Rugelii Dene. 78 



5. Broad spindle-shaped, blunt at base, flattened on 



one side Digitaria sanguinalis (L.) Scop. 1 



4. Less than .6 mm. broad. 



5. Base drawn out into a long acute point, not jet black. 



6. Over 2.8 mm. long, dark green-brown 



Eupatorium purpureum L. 81 



6. Less than 2.8 mm. long, dark gray-brown 



Eupatorium perfoliatum L. 82 



5. Base not drawn out into acute base, jet black. 

 6. Nearly square in cross section, 20 to 30 longi- 

 tudinal lines Rudbeckia hirta L. 91 



