PLATE LVII. BUR OAK. 



1. Flowering brancli with immature leaves, (s) staminate blossoms, (p) pistillate blossoiiis, s S. 



2. Branch with mature leaves and mature acorns, x i, 



3. An acorn cup. x h. 



4. An acorn, x h. 



5. A winter branch showing buds, leaf-scars, and raised corky ridges, x s. 



6. Terminal section of winter branch showing bud with overlapping scales and leaf scar with 



bundle-scars, enlarged. 



7. Basal bud-scale with hairy margin, enlarged. 



«• Apical bud-scale with hairy serrate margin, enlarged. 



