RHAMNACEAE. 221 



Ovary 2-lobed, 2-celled; styles 2, inserted between the 

 lobes. Fruit of 2 long-winged samaras, joined at the 

 base and 1-seeded or rarely 2-seeded. Seeds compressed, 

 ascending; cotyledons thin, folded. 



1. ACER L. Maple. 

 Characters of the family. 



1. A. macrophyllum Pursh. Becoming a tall tree with thick 

 rough and furrowed bark; leaves large, deeply 3-5-parted, the lobes 

 irregular, coarsely toothed, soft pubescent when young, becoming 

 glabrate above and minutely puberulent below; flowers polygamous, 

 in many-flowered drooping racemes; sepals and petals rather broad, 

 nearly equal; filaments pubescent at the base, inserted above the 

 disk; anthers sagittate; carpels covered with stiff tawny hairs; 

 wings 2.5-4 cm. long, diverging at an acute angle. 



Mountain canyons between 3000 and 6000 feet. 



Family 60. RHAMNACEAE. Buckthorn Family. 



Erect or climbing shrubs or small trees, often thorny. 

 Leaves simple, stipulate, generally alternate. Stipules 

 small, deciduous. Inflorescence commonly of axillary or 

 terminal cymes or panicles. Flowers small, regular, per- 

 fect or polygamous. Calyx-tube obconic or cylindric, 

 the limb 4-5-toothed. Petals 4-5, inserted on the calyx, 

 sometimes wanting. Stamens 4-5, inserted with the 

 petals and opposite them; anthers short, versatile. Disk 

 fleshy. Ovary sessile, free from or immersed in the disk, 

 2-5-celled; ovules 1 in each cell, anatropous, ascending. 

 Fruit a drupe or capsule, often 3-celled. Endosperm 

 fleshy, rarely none; embryo large; cotyledons flat. 



Petals clawless or wanting. 1. Rhamnus. 



Petals long-clawed. 2. Ceanothus. 



1. RHAMNUS L. Buckthorn. 



Shrubs or small trees with alternate pinnately veined 

 (in ours) evergreen leaves, and small axillary cymose 

 perfect or polygamous flowers. Calyx-tube urceolate, 

 its limb 4-5-toothed. Petals 4-5, nearly sessile, some- 

 what emarginate and hooded, or none. Disk free from 



