﻿360 Tlie New York State College of Forestrij 



Numbered among these are some of onr best timber trees, pro- 

 ducing hard and strong woods excellent for structural purposes, 

 furniture, interior finish, tight cooperage, etc. A number of 

 natural hybrids have been described. 



Leaves alternate, simple, deciduous or persistent, entire, pinuately lobed 

 or variously toothed, often very variable on the same tree; stipules scarious, 

 caducous or occasionally pesistent. Floxvers monoecious, appearing with or 

 before the leaves; staminate flowers in clustered, drooping, interrupted aments 

 arising from the axils of the leaves of the previous year, the axils of the 

 inner scales of the terminal bud, or of the leaves of the year; calyx yellowish 

 green, campanulate, 4-7 lobed or divided; stamens 4-12 with filiform exserted 

 filaments and yellow anthers; pistillate flowers solitary or in few-flowered 

 spikes from the axils of leaves of the year, each flower subtended by a bract 

 and two bracteoles; calyx urn-shaped, adnata to the ovary, with short cam- 

 panulate 6-lobed limb ; pistU consisting of an incomplete, mostly 3-celled ovary 

 which is nearly enclosed in an accrescent involucre of imbricated scales, sur- 

 mounted by 3 short or elongated styles. Fruit an ovoid-oblong or subglobose 

 1-seeded nut (acorn) maturing in 1-2 years, subtended at the base and more 

 or less enveloped in a woody cup (involucre) of imbricated, partly united 

 scales; cotyledons fleshy, plano-convex and entire. 



KEY TO THE SPECIES page 



1. Acorns maturing at the end of the first'season; shell of acorn g'abrous on the 

 inner surface ; leaves and their lobes obtuse (rarely with teeth and then 



never bristle tipped) , bark pale, often scaly (White Oaks) 2 



1. Acorns maturing at the end of the second season; shell of acorn tomentose 

 on the iimer surface; leaves with bristle-tipped lobes or entire; bark dark, 



furrowed (Black Oaks) 7 



2. Leaves pinnately lobed or lyrate-pinnatified 3 



2. Leaves coarsely sinuate-toothed 5 



3. Mature leaves glabrous beneath Q. alba 175 



3. Mature leaves pubescent or tomentose beneath 4 



4. Mature leaves pubescent beneath; upper scales of the acorn-cup not 



awned Q. stellata 177 



4. Mature leaves white tomentose beneath; upper scales of the acorn-cup 



long-awned Q. macrocarpa 179 



5. Mature leaves hoary tomentose beneath; fruit long-stalked, the peduncle 



longer than the petioles Q. bicolor 181 



5. Mature leaves pubescent beneath; fruit sessile or short-stalked 6 



6. Leaves with acut« or pointed teeth; mature bark ashy-gray, shallowly 



fissured Q. JNIuhlenbergii 183 



6. Leaves with somewhat rounded teeth; mature bark dark brown to black, 



deeply fissured Q. Prinus 185 



7. Leaves pinnately lobed or pinnatifid S 



7. Leaves entire or 3-5 lobed at the summit 12 



8. Longest lobes of the leaf about equaling the breadth of the middle portion 



of leaf 9 



8. Longest lobes of^the leaf 2^or more times the breadth of the middle portion 



of the leaf ' 10 



9. Cup saucer-shaped Q. rubra 187 



9. Cup turbinate Q. rubra, \ ar. ambigua 193 



10. Cup saucer-shaped Q. palustris 189 



10. Cup turbinate 11 



11. Scales of the cup hoary, the upper loosely imbricated Q. velutina 195 



11. Scales of the cup puberulous, the upper closely imbricated Q. coccinea 191 



12. Mature leaves rusty-pubescent beneath; cup turbinate. ..Q. marilandica 197 

 12. Mature leaves glabrous beneath; cup saucer-shaped Q. phellos 199 



