PLATE LXVIII. BLACK JACK OAK. 



1. Flowering branch with immature leaves, (s) staminate blossoms, (p) pistillate blossoms, 



fi) immature acorns, x |. 



2. Brancli with mature leaves, immature and mature acorns, x i. , 



3. An acorn cup, x i. 



4. An acorn, x J. 



5. Winter twig with immature acorns, buds, and loaf-scars, x i. 



6. Section of a winter twig, enlarged. 



