FAGACEAE (BEECH FAMILY) 141 



branches during the winter, opening in the spring before the leaves develop: 

 fertile aments erect, their scales becoming woody, persistent for a timfe after 

 the small, compressed, scarcely winged nuts have fallen. — The common Alder 

 on all the streams of this region. 



30. FAGACEAE Drude. Beech Family 



Shrubs or trees, with deciduous or evergreen alternate petioled leaves. 

 Flowers monoecious; the staminate in aments; the pistillate sohtary or few in 

 a cluster, subtended by an involucre (of more or less united bracts), which 

 becomes a bur or cup. Petals none. Staminate flowers with a 4-7-lobed 

 perianth and 4-20 stamens on slender filaments; the pistillate with an vu'n- 

 shaped perianth adnate to the few-celled ovary; ovules 1-2 in each cell, only 

 1 maturing; styles linear, as many as the cells in the ovary. Fruit a 1-seeded 

 nut, with coriaceous or bony exooarp. 



1. QUERCUS L. Oak 



Shrubs or trees. Leaves in ours mostly deciduous. Flowers small, green or 

 yellowish; the staminate numerous, in slender drooping aments; the pistillate 

 solitary, in many-bracted involucres. Staminate flowers subtended by 

 caducous bracts, consisting of a mostly 6-lobed perianth and 5-12 stamens. 

 Pistillate flowers with an urn-shaped calyx adnate to a 3-celled ovary. Fruit 

 consisting of the imbricated and imited bracts of the involucre (cup), sub- 

 tending or nearly inclosing the coriaceous nut (acorn). 



Upper scales of the cup with caudate prolongations . . . . 1. Q. macrocarpa. 

 Upper scales of the cup not prolonged. 

 Leaves deciduous, lobed or divided. 



Densely and softly short-villous beneath 2. Q. utahensis. 



Glabrate or pubescent (especially on the veins) benea^. 



Cup shallow, covering less than one fourth of the nut . , 3, Q. Vreelandii. 

 Cup deeper, covering more than one fourth of the nut. 



Leaves thin and almost glabrous . . '. , . , 4. Q. leptophylla. 

 Leaves firm, puberulent beneath. 



Nut obtuse 5. Q. Guiinisonii. 



Nut acute 6. Q. Gambellii; 



Leaves persistent, from nearly entire to undulate toothed . . 7. Q. undulata. 



1. Quercus_ macrocarpa Michx. Hist. Chens Am. No. 2. 1801. Becoming 

 a large tree with gray flaky bark: leaves variable, obovate or oblorig-bbovate, 

 irregularly lobed, or pinnatifid, or deeply undulate, at maturity green and 

 shining above, grayish-white tomentulose below, 8-16 cm. long: styles short: 

 fruit subsessile; cup subglobose or hemispheric, 14-20 mm. in diameter; its 

 bracts floccose, hard, thick, the upper subulate-tipped forming a fringe around 

 the ovoid acorn, which is from half to almost wholly immersed in the cup. 

 Bub Oak or Mossy^ctjp. — ^This valuable tree comes into our range in the 

 Black Hills of South Dakota and Wyoming, where it usually attains fair size, 

 though occasionally scarcely more than a shrub. 



2. Quercus utahensis (DC.) Rydb. Bull. N, Y. Bot. Card. 2: 202, 1901.* 

 A small tree often 10 m. high or more or sometimes only a shrub: bark of 

 young branches light brown and pubescent, bark of the older branches brown 

 or gray; bark of the trunk rough and furrowed: bud-scales thin, brown, some- 

 what hairy and puberulent: petioles about 1 cm. long, puberulent; leaf -blade 

 6-10 cm. long, broadly obovate, deeply divided, often to near the midrib; 

 lobes oblong, roxmded at the apex, the larger usjually again lobed or imdulate; 

 upper siu'face sparingly stellate, in age glabrate, dark green and glossy; lower 



* In his pai)er, " The Oaks of the Continental Divide," north of Mexico, Rydberg has 

 ^ven the species most exhaustive treatment. Indebtedness to his descriptions is gratefully 

 •cknowledeed. 



