110 American Midland Naturalist Monograph No. 2 



13. Mature leaves usually glabrous and glaucous beneath; winter-buds 

 nearly or quite glabrous; acorns 1.5-2 cm. long, 3-4 times the 

 length of the shallow cup; upland woods, common. White Oak 



Q. alba L. 



13. Mature leaves pubescent beneath; acorn-cup one-half to one-third 

 the length of the acorn; buds ovoid, pubescent. 

 14. Young twigs pubescent; lower surface of leaves grayish or 

 brownish stellate-pubescent; mature acorns ovoid, 1-2 cm. 

 long, about 1 cm. in diameter; cup one-third to one-half as 

 long as the acorn, nearly sessile; upland woods, more com- 

 mon in the s. part of the state, but extending northw. to 



Adams, Mason, Coles, and Clark counties. Post Oak 



Q. stellata Wang. 



14. Young twigs glabrous or nearly so; lower surface of leaves 

 whitish tomentulose; mature acorns 2-3.5 cm. long, the cup 

 2-5 cm. in diameter, short-peduncled. 

 15. Upper scales of acorn-cup caudate-acuminate, forming a 

 fringe around the acorn, which is half immersed in the 

 cup; leaf-buds acutish, the terminal 5-8 mm. long; vigor- 

 ous 1 -year-old twigs sometimes with corky ridges; upland 

 woods, common. Bur Oak Q. macrocarpa Michx. 



15. Scales broad, not caudate-acuminate; acorn nearly or quite 

 immersed in the cup; buds obtuse the terminal 2-4 mm. 

 long; swamps and bottomland woods in the s. third of 

 the state. Overcup Oak Q. lyrata Walt. 



12. Leaves angularly dentate, coarsely toothed or merely undulate, but 

 not at all or only slightly lobed. (Chestnut Oaks.) 



16. Leaves elliptical or lanceolate, glossy dark green above, more or 

 less whitish stellate-tomentulose beneath, with 8-13 pairs of 

 lateral veins, each vein ending in an acutish, mucronate, often 

 incurved tooth; acorns nearly sessile, or short-peduncled, 10-18 

 mm. long; hillsides and wooded bluffs, common. [Q. acuminata 



(Michx.) Houba} Chinquapin Oak 



Q. muhlenbergii Engeim. 



16. Leaves obovate, cuneate toward the base, angularly shallowly 



coarsely dentate; acorns 2-3 cm. long. 



17. Leaves regularly obtusely dentate; lateral veins 9-12 pairs; fruit 



sessile or short-peduncled, the peduncles less than 1 cm. 



long; bottomlands and borders of streams, chiefly s. 111. [Q. 



michauxii Nutt.} Q. prinm L. 



17. Leaves undulate-crenate or coarsely sinuate. 



18. Lateral veins 10-16 pairs; fruit sessile or nearly so; hillsides 

 and crests of ridges. Union Co. [Q prinus sensu auth., 

 not L.] Chestnut Oak Q. montana Willd. 



18. Lateral veins 4-8 pairs; fruit on peduncles 2-6 cm. long- 

 alluvial soil, throughout III., except the n.w. part. [Q. 



