116 



7. Quercus macrocarpa Michaux. BUR OAK. Plate 46. Large 

 trees; branchlets of young trees generally develop corky wings which are 

 usually absent on mature trees; leaves on petioles 1-2 cm. long, obovate 

 in outline, generally 1-2.5 dm. long, the margins more or less deeply 

 cut so that there are usually 7 lobes, sometimes only 5, or as many as 

 9 or 11, sometimes the sinuses extend to the midrib, giving the leaf a 

 "skeleton" appearance, the lobes are very irregular in shape and various- 

 ly arranged, but often appear as if in pairs, lobes rounded and ascend- 

 ing, the larger lobes are sometimes somewhat lobed, the three terminal 

 lobes are usually the largest and considered as a whole would equal in 

 size one half or more of the entire leaf area, the base of the leaf is wedge- 

 shape or narrowly rounded; leaves at maturity are dark green and 

 smooth above, or somewhat pubescent along the midrib, a gray-green 

 and woolly pubescent beneath; acorns usually solitary, sometimes in 

 pairs or clusters of three, sessile or on short stalks, sometimes on 

 stalks as long as 2.5 cm.; nuts very variable in size and shape, ovoid to 

 oblong, often very much depressed at the apex, 2-3 cm. long, enclosed 

 from ^ to almost then- entire length in the cup which is fringed at 

 the top; cups thick and large, sometimes 4.5 cm. in diameter: scales 

 tomentose on the back and somewhat tuberculate, blunt near the base 

 of the cup, but at and near the top of the cup they become long attenu- 

 ate and on some trees appear almost bristle like; kernel sweet. 



Distribution. Nova Scotia to Manitoba, south to Georgia and 

 west to Texas and Wyoming. Found in all parts of Indiana, although 

 we have no reports from the knob area where no doubt it is only local. 

 It is a tree of wet woods, low borders of streams, etc.. except among the 

 hills of southern Indiana, it is an occasional tree of the slopes. In 

 favorable habitats it was a frequent to a common tree. Its most 

 constant associates are white elm, swamp white and red oak, linn, 

 green and black ash, shellbark hickory, etc. It is sometimes called 

 mossy-cup oak. 



Remarks. Wood and uses similar to that of white oak. In point 

 of number, size and value it ranks as one of the most valuable trees of 

 the State. Michaux 1 says: "A tree three miles from Troy. Ohio, was 

 measured that was fourteen feet and nine inches in diameter six feet 

 above the ground. The trunk rises about fifty feet without limbs, and 

 with scarcely a perceptible diminution in size." 



7a. Quercus macrocarpa var. olivacformis (Michaux filius) 

 Gray. This variet y is distinguished from the typical form by its shallow 

 cup, and the long oval nut which is often 3 cm. long. The cup is semi- 

 hemispheric, and encloses the nut for about one-half its length. 



iMichaux: Xorth American SUra. J. J. Smith's Trans. Vol. 1:37:1871. 



