144 Trans. Acad. Sci. of St. Louis. 



Plate 1. 



Explanation. — Figs. 1, 2, 3, 4, 5, 6, leaf forms from trees over 20 ft. 

 liigh. 



Plate 2. 



Explanation. — Figs. 7, 8, 9, 10, 11, 12, leaf forms from shrubs under 

 10 ft. high. 



Plate 3. 



Explanation. — Fig. 13, stipules various forms, natural size, the first 

 three, upper line from the same tree, the one at right of second line from a 

 shrub collected at Washington, D. C. ; Figs. 14 and 15, twigs with winter 

 buds, natural size, the former most usual in the arborescent form; Figs. 1& 

 and 17, pistillate catkins, natural size; Fig. 18, stamens partly aduate X 3; 

 Figs. 19, 20, 21, three forms of pistil X 3, with stigmas X 6. 



