EXPLANATION OF THE PLATE. 



Plate DLXVI. Pinus Chihuahtjana. 



1. A branch with staminate flowers, natural size. 



2. A staminate flower, enlarged. 



3. A bract of a staminate flower, enlarged. 



4. Diagram of the involucre of the staminate flower. 



5. An anther, front view, enlarged. 



6. An anther, side view, enlarged. 



7. End of a branch with pistillate flowers, natural size. 



8. A pistillate flower, enlarged. 



9. A scale of a pistillate flower, upper side, with its ovules, enlarged. 



10. A scale of a pistillate flower, lower side, with its bract, enlarged. 



11. A fruiting branch, natural size. 



12. A cone at the end of its second season, natural size. 



13. A cone with its peduncle, natural size, 



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



15. A cluster of leaves, natural size. 



16. A cluster of young leaves, with its sheath, natural size. 



17. Tip of a leaf, enlarged. 



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



