MICHIGAN ACADP^INIY OF SCIENCE. 



2t0 



EXPLANATION OF PLATES. 



Plate VII. Figure a, typical seed of Gradus. 



Figure b, Gradus Rabbit-Ear rogue seed. 



(The baclj ground in both figures is ruled into 1 cm. squares.) 



Plate VIII. Upper part of mature type plant of Gradus. 

 (Four-tenths natural size.) 



Plate IX. Upper part of mature Rabbit-Bar rogue of Gradus. 

 (Four-tenths natural size.) 



Plate X. Figure a. Seedling of typical Gradus, three weeks old. 



Figure b. Seedling of typical Gradus Rabbit-Ear rogue, three weelcs ohl. 

 (Figs, a and bare two-thirds natural size.) 



Plate XI. Figures a, l^, c, are of Type-like, intermediate, and Rogue-like seedlings. 



respectively, from the Fi generation of the cross Gradus type 

 X Gradus Rabbit-Ear rogue. Figures a and c are from the 

 same cross. All the seedlings were tliree weeks old when 

 collected. (Figures a, b, c are two-thirds natural size.) 



Plate XII. a. Young plant of typical Gradus about five weeks old, collected one 

 week before the stipule measurements were made, 

 b. Young plant of Gradus Rabbit-Ear rogue of same age as type plant 

 shown in Plate Xlla. (One-fourth natural size.) 



Plate XIII. Young plant of cross Gradus type X Gradus Rabbit-Ear rogue in the Fi 

 generation. Age of type plant shown in Plate Xlla. (Four- 

 tonths natural size.) 



