Jones: Flora of Illinois, 42. Fagaceae 109 



5. Leaves brownish sfellate-tomentulose beneath; buds conical-fusiform, 



8-10 mm. long; acorn-cups turbinate, 1.5-2 cm. m diameter, enclos- 

 ing half the acorn; upland woods, not common. Black Jack Oak 

 Q. marilandica Muench. 



4. Leaves pinnately 5-9-Iobed or cleft. 



6. Leaves grayish-tomentulose beneath; lobes often falcate; acorn glo- 



bose; cup saucer-shaped; woods, s. III., not common. [Q. pagodae- 



folia Ashe; Q. falcata Michx.] Spanish Oak Q. rubra L. 



6. Leaves glabrous or nearly so, not grayish tomentulose beneath, but 

 often with tufts of hairs in the axils of the principal veins. 



7. Leaves lobed about halfway to the midvein; acorn cup shallow, 

 saucer-shaped; winter-buds nearly glabrous; inner bark gray or 

 reddish; woods, common. [Q. rubra sensu DuRoi, non L.; Q. 



borealis var. maxima (Marsh.) Ashe}. Red Oak 



Q. borealis Michx. f. 



7. Leaves usually cleft more than half-way to the midvein. 



8. Acorn-cup shallow, saucer-shaped, enclosing not more than one- 

 third of the acorn; inner bark gray or reddish; winter buds 

 glabrous or sparsely pubescent. 



9. Acorn-cup 1-1.5 cm. in diameter, the rim only 3-4 mm. high; 



acorn 1-1.5 cm. long; woods along streams. Pin Oak 



Q. palustris Muench. 



9. Acorn-cup 16-22 mm. in diam-eter, the rim 5 mm. or more 



high; acorn 1.8-2.5 cm. long; woods near streams, s. III. 



[Q. schneck't Britt.] Q. shumardii Buckl. 



8. Acorn-cup hemispherical or turbinate enclosing about one-half 

 of the mature acorn. 



10. Scales of the acorn-cup closely appressed; winter buds coni- 



cal, sparsely pubescent to glabrous. 



11. Acorn-cup 15-25 mm. in diameter, the scales glabrate, 

 glossy; acorn ovoid; inner bark reddish or gray; upland 



woods, s. 111. Scarlet Oak Q. coccinea Wang. 



11. Acorn-cup 10-15 mm. in diameter, the scales puberulent; 

 acorn ellipsoid; inner bark yellowish; upland woods, n. 

 III. Northern Pin Oak. Hill's Oak. Discovered near 

 Chicago in 1891, by the pioneer Illinois botanist, E. J. 



Hill Q. ellipsotdalts E. J. Hill 



10. Scales of the acorn-cup pubescent, loosely imbricated, the 

 upper forming a fringed border; cup 18-25 mm. in diam- 

 eter; winter-buds large, angular, densely grayish pubescent; 

 inner bark yellowish or orange; upland woods, common. 



Black Oak Q. yelutina Lam. 



3. Leaf-lobes not bristle-tipped; acorns maturing in the autumn of the first 

 year. 

 12. Leaves irregularly deeply lobed, often somewhat lyrate. (White 

 Oaks.) 



