240 Aceraceae 



5. R. trilobata Nutt. Low branching deciduous aromatic 

 shrub, more or less pubescent when young ; leaves 3-foliate ; the 

 terminal leaflet 2.5-5 cm. long, 3-lobed and coarsely toothed 

 above the middle; the lateral pair 1-1.5 cm. long, round-ovate, 

 scarcely lobed, crenate; flowers yellowish, appearing before the 

 leaves in short spike-like clusters ; drupes viscid-hirsute. 



Frequent in the foothills and mountains throughout our range. March. 



Family 51. ACERACEAE. MAPLE FAMILY. . 



Trees or shrubs with watery often saccharine sap, 

 opposite simple and palmately lobed or pinnate leaves, 

 and axillary or terminal cymose or racemose regular polyg- 

 amous or dioecious flowers. Calyx generally 5-parted, 

 the segments imbricated. Petals of the same number or 

 none. Disk thick, annular, lobed, sometimes obsolete. 

 Stamens 4-12, often 8 ; filaments filiform. 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 ; cotyle- 

 dons thin, folded. 



1. ACER L. MAPLE. 



Characters of the family. 



1. A. macrophyUum 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 polyg- 

 amous, in many-flowered drooping racemes ; sepals and petals 

 rather broad, nearly equal; filaments pubescent at the base, in- 

 serted above the disk ; anthers sagittate ; carpels covered with stiff 

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



Occasional in all our mountains in canyons between 3000 and 6000 feet. 



Family 52. RHAMNACEAE. BUCKTHORN FAMILY. 



Erect or climbing shrubs or small trees, often thorny. 

 Leaves simple, stipulate, generally alternate. Stipules 



