Note:--In collecting leaf specimens of oaks for identification it should be borne in mind that the foliage is quite variable. The leaves of seedlings, coppice shoots and of vigorous shoots of old trees sometimes vary considerably in size, form and leaf-margins. Also leaves of old trees that grow in the shade usually have the margins more nearly entire than the typical leaves. For example leaves may be found on the lower and interior branches of a pin oak which are not lobed to beyond the middle, which throws them into the red oak group. Bark gray, (except in No. 5) more or less scaly; mature leaves never with bristle tips; fruit maturing the first year. Mature leaves smooth beneath. 1 Q. alba. Mature leaves pubescent beneath. Primary veins beneath show regular pinnate venation. Some of the primary veins beneath end in a sinus. 2 Q. bicolor. All primary veins beneath end in teeth of the margin. Tips of leaves of fruiting branches sharp-pointed, usually forming an acute angle; fruit sessile or nearly so. 3 Q. Muhlenbergii. Tips of leaves of fruiting branches rounded or if sharp-pointed, it rarely forms an acute angle; fruit peduncled. Petioles green and woolly pubescent beneath (rarely almost glabrous); under surface of leaves velvety to the touch; bark gray, scaly, of the white oak type; trees of low ground. 4 Q. Michauxii. Petioles yellowish and smooth beneath, or rarely somewhat pubescent; under surface of leaves not velvety to the touch; bark dark, and tight, of the red oak type; trees of high ground (in Indiana confined to the "knobstone" area). 5 Q. Prinus. Primary veins beneath show irregular venation. Last year's growth pubescent; acorns generally less than 12 mm. in diameter. 6 Q. stellata. Last year's growth glabrous or nearly so; acorns more than 12 mm. in diameter. Leaves sinuate dentate, sometimes lobed near the base, velvety to the touch beneath; peduncles of fruit longer than the petioles. 2 Q. bicolor. Leaves irregularly lobed, harsh or rarely velvety or smooth to the touch beneath; peduncles of fruit shorter than the petioles. Cup of fruit fringed; apex of lobes of leaves generally rounded; trees of lowland. 7 Q. macrocarpa.