EXPLANATION OF THE PLATES. 
Pratt LXXXIV. Acer PENNSYLVANICUM. 
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. A branch with staminate flowers, natural size. 
. A branch with pistillate flowers, natural size. 
Diagram of a flower. 
. Vertical section of a staminate flower, enlarged. 
. An anther, front and back views, enlarged. 
. Vertical section of a pistillate flower, enlarged. 
Oo PP we 
. Vertical section of an ovary, enlarged. 
. An ovule, much magnified. 
co CO 
. A winter branchlet, natural size. 
Pirate LXXXV. Acer PENNSYLVANICUM. 
1. A fruiting branch, natural size. 
2. Vertical section of a fruit, natural size. 
3. Vertical section of a seed, enlarged. 
4. An embryo, enlarged. 
