200 FAGACEAE 



Scales of the cups decidedly corky-thickened on the back. 



Leaves decidedly crisp, sinuately lobed; lobes distinctly spinulose-tipped. 



Leaves flat, sinuate-dentate or entire; teeth mucronate, or sometimes' slio-htlv 



spmulose-tipped. ° ^ 



Acorns &-7 mm thick; cup shallow, enclosing about one-third of the acorn; 



lea ves usually smuate-dentate. 13. Q. undulata. 



Acorns about 1 cm. thick or more; cup deeper, enclosing about half of the 



acorn. 



Leaves usually entire, except those of the young shoots. 



Leaves lobed, with few (5-7) lobes. lo' Q vanciloba 



Scales of the cups thin, only slightly thickened on the back; leaves glabrate and 

 shining above in age. - 16 n Wilcoxii 



Cup more or less turbinate; acorns elongated-ovoid. 17." q'. turbinella. 



1. Q. macrocarpa Michx. A tree 10-50 m. high; leaf-blades obovate, 

 irregularly round-lobed, usually pinnately divided below the middle, bright green 

 and shining abover grayish tomentulose beneath, 1-2 dm. long; fruit short- 

 peduncled; cup hemispheric, 1-2.5 cm. in diameter; scales floccose, thick, ovate 

 or lanceolate, the upper subulate-tipped; acorns 1.5-2.5 cm. long, ovoid. Bur 

 O.^K. Mossy-cup Oak. Rich soil: N.S.-^Pa.— Tex.— (? Wyo.)— S.D.— Sask. 

 Flmn — Submont. My-Je. 



2. Q, submollis Rydb. Shrub or small tree; leaf-blades obovate in outhne, 

 deeply pmnatifid at least two-thirds to the midrib, with oblong segments, rounded 

 at the apex, glabrous and shining above, densely and softly pubescent beneath; 

 fnut sessile; cup depressed-hemispheric, about 15 mm. broad; acorn obtuse, 12- 

 15 mm. long. Mountain sides: Ariz.— s Utah— N.M. Son.— Submont. 



3. Q. utahensis (A. DC.) Rydb. A small tree, sometimes 10 m. high, or 

 more often only a shrub; leaf-blades &-10 cm. long, broadly obovate, deeply 

 divided, often to near the midrib ; lobes oblong, rounded at the apex, the larger 

 usually again lobed or undulate; upper surface sparingly steUate, in age glabrate, 

 dark green and glossy; fruit subsessile; cup hemispheric, 12-15 mm. in diameter; 

 scales pubescent, ovate; acorn 15-20 mm. long, light brown. Utah Oak. Hills 

 and mountains: Utah— Colo.— N.M.— Ariz. Submont.— -Mont. My. 



4. Q. Vreelandii Rydb. A small shrub 1-1.5 m. high; young branches 

 brown, puberulent; leaf-blades 5-7 cm. long, obovate, deeply lobed about two- 

 thirds to the midrib, thick, firm; lobes rounded, "the larger often lobed or sinuate; 

 upper surface soon glabrate, bright green and rather dull ; lower surface slightly 

 paler; fruit subsessile; scales ovate and very corky on the back; acorn about 15 

 mm. long, hght brown. Hills and bench-lands: Colo.— N.M. Submont. My. 



6. Q. leptophylla Rydb. A tree 10-15 m. high; young twigs brownish or 

 purplish, slightly pubescent at first; leaf-blades broadly obovate, very^thin, 

 pmnately 5-9-lobed scarcely more than half way to the midrib; lobes rounded; 

 upper surface soon glabrate, bright green, but not very glossy;, lower surface 

 paler; fruit subsessile; cup hemispheric, about 15 mm. wide; scales ovate-lanceo- 

 late, obtuse, only slightly thickened on the back. Along mountain streams: 

 Colo. — N.M. Submont. — Mont. My, 



6. Q. Gunnisonii (Torr.) Rydb. A low shrub 1-3 m. high, forming 

 chapparels; leaf-blades with rounded lobes, usuallv directed forward, very thick, 

 pale and bluish green above, soon glabrate, scarcely paler beneath; fruit sub- 

 sessile; cup rather deep, 12-15 mm. in diameter, hemispheric; scales ovate, corky- 

 thickened on the back; acorns barrel-shaped, obtuse. Dry hillsides and table- 

 lands: Colo.— N.M.— Ariz.— Utah. Submont. My. 



7. Q. Gambellii Nutt. A shrub 3-5 m. high; young twigs light brown and 

 puberulent; leaf-blades broadly obovate in outUne, thinner than in the preced- 

 mg; upper surface glabrate, green, lower surface only slightly paler, lobes rounded; 

 fruit subsessile; cup hemispheric or somewhat turbinate; acorn ovoid, acute or 

 obtuse, about 15 mm. long. Q. nitescens Rydb. Hills and table-lands: Wyo — 

 N.M. — Utah. Submont. —Mont. My-Je. 



1- i.®V^* iiovoJ^exicana (A. DC.) Rydb. A shrub 3-5 m. high; young branches 

 light bro^Ti, or grayish, sparingly puberulent or glabrous; leaf-blades obovate in 

 outline, deeply divided about three-fourths the di.^ftannft t,n thr^ mJrlrSK vorv 



