MYRICACEAE. 119 



or dioecious; perianth none; stamens 2-16; ovary 1-celled, 1- 

 ovuled; fruit a drupe-like nut. 



146. MYRICA. Bayberry. 



Shrubs or small trees with dentate or serrate leaves ; fruit coated 

 with wax. 



Leaves deciduous, obtuse, serrate at apex. M. gale. 



Leaves evergreen, acute, serrate from near the base. M. California!. 



Myrica gale L. Sweet Gale. Dioecious low shrub, 1-2 m. high; leaves 

 oblanceolate, 2-6 cm. long, obtuse, serrate only at the apex, deciduous, ap- 

 pearing after the aments; staminate aments in clusters; pistillate aments 

 subglobose in fruit, the nutlets resinous- waxy, each bearing two winglike bracts 

 that are adnate at the base. 



Common along lake margins. 



Myrica californica Cham. Monoecious evergreen shrub or small tree, 

 1-10 m. high; leaves oblanceolate, acute, serrate; aments bearing both stami- 

 nate and pistillate flowers, the latter near the apex; nutlet purplish, papillose, 

 with 2 minute bractlets at base. 



Only along the ocean coast. 



Family 27. BETULACEAE. Birch Family. 



Trees or shrubs; leaves alternate, petioled, simple, with de- 

 ciduous stipules; flowers small, monoecious, in linear-cylindric, 

 oblong or subglobose aments; staminate aments pendulous; 

 pistillate aments erect, spreading or drooping, spike-like or 

 capitate; staminate flowers 1-3 in the axil of each bract, with a 

 membranous 2-4-parted calyx, or calyx none, and 2-10 hypogy- 

 nous stamens ; pistillate flowers with or without a calyx adnate to 

 the solitary 1-2-celled ovary; ovules 1-2 in each cavity; fruit a 

 small compressed or ovoid-globose mostly 1-celled and 1 -seeded 

 nut or samara ; endosperm none. 



Fruit a nut enclosed in a leafy involucre. 148. Corylus, 120. 

 Fruit cone-like, without an involucre. 



Cone scales thin, deciduous; stamens 2. 147. Betula, 119. 



Cone scales thick, persistent; stamens 4. 149. Alnus, 120. 



147. BETULA. Birch. 



Trees and shrubs; leaves dentate or serrate; buds scaly; 

 flowers all in aments, expanding before and with the leaves; 

 pistillate aments erect or spreading; staminate flowers about 3 

 in the axil of each bract, with a membranous usually 4-toothed 

 perianth and 2 stamens, and subtended by 2 bractlets; pistillate 

 flowers 2 or 3 (rarely 1) in the axil of each bract; perianth none; 



