EXPLANATION OF THE PLATE. 



Plate DCVI. Tsuga Mektensiana. 



1. A branch with staminate flowers, natural size. 



2. A staminate flower, enlarged. 



3. An anther, front view, enlarged. 



4. An anther, side view, enlarged. 



5. A branch with pistillate flowers, natural size. 



6. A pistillate flower, enlarged. 



i 



7. A scale of a pistillate flower, upper side, with its bract and ovules, enlarged. 



8. A fruiting branch, natural size. 



9. Portion of a top of a tree from BaranofB Island with erect cones, natural size. 



10. A cone from the Coeur d'Alene Mountains, Idaho. 



11. A cone-scale, upper side, with its seeds, natural size. 



12. A cone-scale, lower side, with its bract, natural size. 



13. A scale of a small C(Bur d'AIene cone, upper side, with its seeds, natural size. 



14. A scale of a small Cceur d'Alene cone, lower side, with its bract, natural size. 



15. A seed, enlarged. 



16. Vertical section of a seed, enlarged. 



17. An embryo, enlarged. 



18. Cross section of a leaf, magnified fifteen diameters. 



