510 



BETULACEAE 



10-12 mm. long; fruit globose, 20-30 mm. in diameter, witli a thin dark brown soft 

 pubescent husk ; nut globose, slightly compressed, with a few remote shallow grooves, thin-walled. 



In canons, especially on north slopes, Upper Sonoran Zone; coast mountains of Ventura County to the 

 Santa Ana and San Bernardino Mountains, California. Type locality: not indicated. 



Juglans californica hindsii Jepson, Fl. Calif. 1: 365. 1909. Tree 15-25 m. high with a trunk 3-15 dm. in 

 diameter; leaflets mostly lanceolate and acuminate occasionally oblong-lanceolate, 5-7 cm. long ;_ fruit 3-5 

 cm. in diameter. As pointed out by Jepson these northern trees are found about ancient Indian village 

 sites and were probably introduced' from the southern part of the state. Walnut and Lafayette Creeks, 

 Contra Costa County ; near Walnut Grove, and on the east slope of the Napa Range near Wooden 

 Valley. Often planted as a shade tree, and used as a stock for the English walnut. 



Family 28. BETULACEAE. 



Birch Family. 



Trees and shrubs without terminal buds, the branches prolonged by one of the 

 upper naked axillary buds. Leaves deciduous, alternate, simple and usually deeply 

 serrate. Flowers monoecious, both kinds in aments, usually appearing before the 

 leaves. Staminate aments pendulous, with 1-3 flowers in the axils of each bract. 

 Calyx membranous, 2-4-parted or none, stamens 1-10. Pistillate aments erect or 

 drooping, spike-like or capitate. Calyx when present adnate to the 1-2-celled ovary. 

 Style 2-cleft. Ovules 1 or 2 in each cell, pendulous. Fruit a small 1-seeded winged 

 nutlet in spike-like clusters, or the nut larger, enclosed by an involucre formed by 

 the enlarged bracts, and solitary or few in a cluster. Endosperm none ; cotyledons 

 fleshy. 



Six genera confined to the northern hemisphere. 



Fruit a nut enclosed in an involucre; staminate flowers solitary in the axils of the ament scales. 1. Corylits. 

 Fruit a winged nutlet in the axils of the ament scales; staminate flowers usually three in the axils of the 

 ament scales. 



Pistillate aments solitary, their scales thin, 3-lohed, deciduoxis. 2. tsetula. 



Pistillate aments racemose, their scales erose, persistent, becoming thick and woody. 3. Abuts. 



1. CORYLUS [Tourn.] L. Sp. PL 998. 1753. 



Shrubs with thin double-toothed leaves folded lengthwise in the bud, flowering in early 

 spring before the leaves. Staminate flowers in drooping ainents at the ends of the branches 

 of the preceding year ; the flowers solitary in the axils of the bracts, of about 4 stamens and 

 2 bractlets. Calyx none. Pistillate flowers several in a rounded scaly bud terminating the 

 branchlet, 2 to each bract, with 2 bractlets. Calyx adherent to the ovary; style short; 

 stigmas 2, elongated, bright red. Fruit a smooth nut enclosed by an involucre formed by 

 the enlarged and united bractlets. [Name Greek, from the helmet-like involucre.] 



About 12 species distributed over the cooler parts of the north temperate zone. Besides the following 

 2 others occur in eastern North America. Type species, Coryitis arellana L. 



I. Corylus californica (A. DC.) Rose. California Hazelnut. Fig. 1240. 



Corvlus rostrata californica A. DC. Prod. 16-: 133. 

 i864. 



Corylus californica Rose, Card. & Forest, 8: 263. 

 1895. 



A loose spreading shrub, 2-3.5 m. high, 

 with smooth bark, and glandular-pubescent 

 branchlets becoming glabrous the second 

 year. Leaves rounded to obovate, 3.5-8 cm. 

 long, obtuse or abruptly acute, doubly ser- 

 rate, sometimes obscurely 3-lobed, glandu- 

 lar-hairy, pale beneath ; anthers with a 

 sparse tuft of hairs at the apex ; involucre 

 hispid, prolonged above the nut into a 

 lacinate tube, 15-25 mm. long; nut ovoid, 

 12-15 mm. long. 



Moist cafion slopes or along streams. Transi- 

 tion Zone; British Columbia to the southern Sierra 

 Nevada and the Santa Cruz Mountains, California. 

 Type locality: Santa Cruz, California. 



