94 BETULACEAE. 



late flowers solitary or several together on a terminal 

 peduncle at the end of shoots of the season; calyx 4- 

 lobed, with 4 small petals adnate to the ovary at the 

 sinuses; styles fimbriate, very short. Drupe large, glo- 

 bose or ovoid, the exocarp somewhat fleshy, the endo- 

 carp rugose or sculptured, 2-4-celled at the base. 



1. J. calif ornica Wats. Arborescent shrub growing in clumps, 

 5 m. high, or rarely a tree and attaining a height of 15 m., more or 

 less tomentose, sometimes nearly glabrous; leaves 15-25 cm. long; 

 leaflets 11-17, oblong-lanceolate, serrate, 4-6 crn. long; aments 

 often in pairs, 7-12 cm. long; perianth of staminate flowers 3 mm. 

 long; stamens 30-40; drupe globose, slightly compressed, 1.5-2.5 cm. 

 in diameter; nut shallowly sulcate. 



Confined mostly to the foothills below 3000 feet. Frequent in 

 the Santa Monica Mountains and Puente Hills, less so on the south- 

 ern borders of the San Gabriel, San Bernardino and Santa Ana 

 Mountains. 



Family 20. BETULACEAE. Birch Family. 



Monoecious trees or shrubs, with alternate petloled 

 simple leaves and small flowers In aments. Staminate 

 aments pendulous, with 1-3 flowers In the axils of each 

 bract, consisting of a membranous 2-4-parted calyx or 

 none, and 1-10 stamens. Pistillate aments erect or 

 drooping, splke-like or capitate, their flowers with or 

 without a calyx adnate to the solitary 1-2-celled ovary; 

 style 2-cleft; ovules 1-2 in each cell, pendulous. Fruit 

 a small compound or ovold-globose nut or samara. En- 

 dosperm none; cotyledons fleshy. 



1. ALNUS Gaertn. Alder. 



Shrubs or trees with dentate or serrulate leaves, and 

 both pistillate and staminate flowers In aments; the 

 staminate pendulous; the pistillate erect, clustered. 

 Staminate flowers 3-6 In each axil, consisting of a mostly 

 4-parted perianth, 1-4 stamens and subtended by 2-4 

 minute bractlets; ovary 2-celled; bracts woody, per- 

 sistent, 5-toothed or erose. Nut small, compressed, 

 winged or wingless. 



1. A. rhombifolia Nutt. Tree 7-14 m. high, with a light gray 

 trunk; leaves narrowly or broadly ovate to elliptic, 2.5-10 cm. 

 long, irregularly serrulate, somewhat pubescent beneath; staminate 



