EXPLANATION OF THE PLATE. 



Plate CCCXI. Ulmus Americana. 



1. A flowering branch, natural size. 



2. A flower, enlarged. 



3. Vertical section of a flower, enlarged. 



4. A stamen, front and rear views, enlarged^ 



5. Vertical section of a pistil, enlarged. 



6. An ovule, much magnified. 



7. A fruiting branch, natural size. 



8. Vertical section of a fruit, enlarged- 



9. A seed, enlarged, 



10. Vertical section of a seed, enlarged. 



11. An embryo, enlarged. 



12. A summer branch, natural size. 



13. A winter branch, natural size. 



