Handbook of Tre.es of the Noetiieen States and Canada. 431 



With broad rounded sinuses; inner barli reddisii Q. coceinea. 



Witli narrow sinuses Q. borealis. 



e' Scales larger, loosely imbricated and fiee at margin of cup ; leaves obovate with 



narrower sinuses ; inner bark yellowish Q. vellutina. 



c' Leaves whitish tomentose beneath and mostly with 



d Short broad lobes ; leaves mostly obovate Q. nana. 



d^ Elongated and more or less falcate lobes ; leaves 



Rounded or obtuse at base, obovate to oblong with 3-5 mostly linear or triangular 



lobes " Q. digitata. 



Cuneate, ovate or oblong with 5-11 mostly falcate lobes. ... Q. pagodaifolia. 

 b^ Leaves ;-!-.5-lobed near the apex or entire, obovate or spatulate 



Wide-obovate, cuneate, rusty pubescent beneath Q. Marilandica. 



Spatulate-obovate, glabrous Q. nigra. 



b' Leaves usually entire and lanceolate to oblong, involute in the bud and 



Linear-oblong, acute at both ends, glabrous Q. Phellos. 



Oblanceolate to oblong, shining dark green above, paler and glabrous beneath. 



Q. laurifolia. 



Oblong-lanceolate to oblong or ovate, pubescent beneath Q. imbricaria. 



a= Acorns maturing in the autumn of the first year ; shells glabrous inside ; abortive ovules 

 basal; stamens 6-8; styles short (White Oaks). 

 b Leaves pinnately lobed or lyrate-pinatifid with lobes rounded at apex (not bristle-tipped) 

 deciduous 

 c Glabrous beneath, obliquely 3-0-Iobed and conduplicate in the bud ; cup shallow. 



Q. alba. 

 c' Pubescent beneath and stellate pubescent above, usually 5-lobed, convolute in the bud. 



Q. minor, 

 c' White tomentose beneath 



Lyrate-pinnatifid ; cup fringed with free ends of scales Q. macrocarpa. 



Deeply 5-9-lobed ; cup not fringed and nearly inclosing the nut Q. lyrata. 

 V Leaves coarsely crenate-toothed 



o Fruit with peduncles much longer than petioles Q. platanoides. 



o Fruit with peduncles shorter than or about equal to the petiole; leaves whitish 

 tomentose beneath 



Bark scaly whitish Q. Michauxli. 



Bark firmly ridged, grayish brown Q. Prinns. 



b' Lea ves coarsely repand-serrate, lanceolate to obovate ; 



Tall trees Q. acuminata. 



Shrubs or very small trees Q. prinoides. 



b' Leaves mostly entire, thick and evergreen Q. Virginiana. 



For species see pp. 138-181 and the foUowing: 



Bear Oak, Bakren Oak or Scrub Oak, Q. nana Sarg. (Syn. Q. ilicifolia Wang., Q. 

 pumila Sudw.). This is an intricately branched shrub ranging from Maine to Virginia, 

 chiefly coastwise, occupying sandy barrens and hillsides and sometimes forming vast and 

 almost impenetrable thickets. Mr. Wm. T. Davis has found it on the Pine Barrens of New 

 Jersey assuming the habit of a small wide-topped tree 18 or 20 ft. in height with trunk 5 or & 

 in. in diameter. It is characterized as follows : Leaves mostly obovate. 2-.5 in. long with 

 3-7 (usually .5) short spreading bristle-tipped lobes, cuneate, more or less pubescent at first, 

 at maturity thick firm lustrous dark green above, whitish pubescent beneath ; petioles short. 

 Flowers staminate aments hairy, often persisting late into the summer; pistillate flowers with 

 red recurved stigmas. Fruit borne in great abundance, mostly solitary or in pairs, sessile or 

 nearly so ; acorns globose-ovoid, about Va in. long and half invested by the usually turbinate- 

 cup of small closely imbricated scales. 



ScRt'B Chestnut Oak. Q. prinoides Willd. A shrubby oak distributed from Maine to 

 North Carolina and westward into Nebraska, Kansas and Texas, occupying rocky slopes and 

 drv sandv nidands and is usuallv only a stolaniferoiis shi'nb fi'om 2-.^ feet in height. West 

 of the Mississippi River it sometimes assumes a tree-like habit of growth but only attaining a 

 height of 10 or 15 ft. with trunk 4 or 5 in. in diameter. In botanical characters it closely 

 resembles Q. acuminata, but with smaller and more remotely lobed leaves and shorter petioles, 

 and acorns with deeper cups and more turgid scales. 



Gray Oak. Q. borealis Michx. f. (also Q. ambigua Michx. f. ). A large tree, occasionally 

 found from Ontario and Quebec to the mountains of North Carolina, bearing leaves like- 

 Q. rubra and fruit like Q. coceinea. It is considered by some a distinct species and by others, 

 and probably more correctly, only an aberrant form of Q. rubra. 



Many natural hybrids are found among the Oaks, some of which have been named and 

 described by early botanists as d'otinet species. The-'r raritv and local distribution, however, 

 and occurrence only in localities where certain other Oaks whose characters they more or less 

 share in common occur seem conclusive evidence of hybridization. The following ca,ses have 

 been noted : 



Q. Rudkini Britton ^= Q. Marilandica X Q. Phellos. 



Q. Brittoni W. T. Davis = Q. Marilandica X Q. nana. 



Q. heterophylla Michx. = Q. Phellos X Q. rubra. 



Q. Leana Nutt. = Q. imbricaria X (?. vclutina. 



Q. trulentata Engelm. = O. imb'-icaria X Q. Marilandica. 



Other hybrids have been found which have not been named. 



