WOOTON AND STANDLEY FLORA OF NEW MEXICO. 163 



large rounded top 12 to 15 meters high. Its leaflets are broadly lanceolate, 6 to 9 

 cm. long, not revolute-margined but serrate. The nut is 20 to 25 mm. in diameter. 



This species has been confused with a Californian one (/. californwa S. Wats.) from 

 which it is said, by those who know both, to be distinct. The Californian plant is 

 found in the Sacramento Valley. 



Our native walnuts, this species in particular, are often known by the native name 

 of "nogal." 



Order 19. FAGALES. 



KEY TO THE FAMILIES. 



Staminate and pistillate flowers in aments; fruit never 



with a bur or cup 32. BETULACEAE (p. 163). 



Staminate flowers in aments. the pistillate often soli- 

 tary; fruit with a bur or cup 33. FAGACEAE (p. 164). 



32. BETULACEAE. Birch Family. 



Monoecious or rarely dioecious trees or slirubs with alternate simple leaves and 

 deciduous stipules; sterile flowers in catkins; fertile flowers clustered, spicate, or in 

 scaly catkins; fruit a 1-celled and 1-seeded nut with or without a foliaceous involucre. 



KEY TO THE GENERA. 



Ovary inclosed in a bladdery bag 1. Ostrya (p. 163 1. 



Ovary not inclosed in a bladdery bag. 



Stamens 2; bracts of the mature pistillate aments membra- 

 nous, usually 3-lobed, deciduous with the nut 2. Betula (p. 163). 



Stamens usually 4; bracts of the mature pistillate amenta 



thickened and woody, erose or toothed, persistent 3. Axnus (p. 164 1. 



1. OSTRYA Scop. Hop hornbeam. 



A small tree; sterile flowers consisting of several stamens in the axil of each bract; 

 fertile flowers a pair to each deciduous bract, inclosed in a bractlet, this in fruit 

 becoming a bladdery bag, the involucres forming a kind of strobile resembling t hat 

 of the hop. 



1. Ostrya baileyi Rose, Contr. U. S. Nat. Herb. 8: 293. L905. 

 Type locality: Guadalupe Mountains, Texas. 



Range: Known only from the type locality. 



The type was collected only two miles from the Now Mexico lino, and the Bp< 

 with but little doubt, occurs at the north end of the range in New Mexico, 



2. BETULA L. Birch. 



Small tree or large shrub with slender stems; Bterile flowers 3 to each shield-shaped 

 scale of the calkin; fertile flowers 2 or 3 to each 3-lobed bract, the bracts thin, decidu- 

 ous; fertile catkins ovoid tocylindric. 



1. Betula fontinalis Sarg. Bot. Gaz. 31: 239. 1901. 



Betula micropkylla fontinalis Janes, Contr. West. Bot. 12:77. 1908. 



Type locality: "On the Sweetwater, one of the branches of the Pis 



Hanoi:: British America to Colorado and New Mexico. 



New Mexico: San Juan Valley; Tunitcha Mountains; Paquate. Along streams, 

 in the Upper Sonoran and Transition Bones. 



