EXPLANATION OF THE PLATE. 



Plate DXLIX. Pinus quadrifolia. 



1. A branch with staminate flowers, natural size. 



2. A staminate flower, enlarged. 



3. Diagram of the involucre of the staminate flower. 



4. Bract of a staminate flower, enlarged. 



5. An anther, side view, enlarged. 



6. An anther, front view, enlarged. 



7. A branch with pistillate flowers, natural size. 



8. A pistillate flower, enlarged. 



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



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



11. A fruiting branch, natural size. 



12. A cone-scale, upper side, natural size. 



13. A seed, natural size. 



14. Vertical section of a seed, enlarged. 



15. An embryo, enlarged. 



16. Tip of a leaf, enlarged. 



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



18. A seedling plant, natural size. 



