ACERACEAE. 227 



1. Acer glabrum Torr. In canons, on hillsides and along streams, from 

 W. Neb. and Wyo. to N. M. and Utah. Alt. 4000-9000 ft. Headwaters of 

 Clear Creek; Hinsdale Co.; Pike's Peak; near Pagosa Peak; near La Plata 

 Post Office ; Idaho Springs ; foot-hills west of Ft. Collins ; South Cheyenne 

 Canon ; Colorado Springs ; Wahatoya Canon ; Ute Pass ; southeast of Ouray ; 

 along Uncompahgre River near Ouray; Rist Canon; Dillon Canon; gulch 

 west of Pennock's ; hills northwest of Soldier Canon ; Howe's Gulch ; Baxter's 

 ranch ; Big Narrows on Poudre ; Ft. Collins ; Dolores ; North Poudre River ; 

 Campton's ranch ; Horsetooth Gulch ; gulch west of Dixon Canon ; Redstone ; 

 mountains between Sunshine and Ward; Eldora to Baltimore. 



2. Acer grandidentatum Nutt. In wooded valleys and canons from Mont, 

 to Tex. and Ariz. Pike's Peak. 



2. RULAC Adans. BOX-ELDER, ASH-LEAVED MAPLE. 



Twigs and petioles essentially glabrous ; leaflets thin, coarsely toothed. 



i. R. Negundo. 

 Twigs and petioles copiously pubescent ; leaflets thick, lobed. 2. R. texana. 



1. Rulac Negundo (L.) Hitchc. (Acer Negundo L. ; Negundo aceroides 

 Moench. ) In low ground and along streams from Vt. and Ida. to Fla. and 

 Tex. Alt. 4000-7000 ft. South Cheyenne Canon ; Colorado Springs. 



2. Rulac texanum (Pax.) Small. (Acer texanum Pax.) Along rivers from 

 Sask. and Mont, to Mo. and Ariz. Alt. 5000-8500 ft. Southeast of Ouray ; 

 Cucharas Valley, near La Veta ; Ft. Collins ; Walsenburg ; Cache la Poudre ; 

 foot-hills near Boulder. 



Order 32. RHAMNALES. 



Sepals manifest ; petals involute ; fruit capsular or drupaceous ; ours shrubs or 



trees. 84. FRANGULACEAE. 



Sepals minute or obsolete ; petals valvate ; fruit a berry ; ours vines with tendrils. 



85. VITACEAE. 



Family 84. FRANGULACEAE DC. BUCKTHORN FAMILY. 



Fruit pulpy; petals small, clawless or wanting ; stigmas usually 2. 



i. I^HAMNUS. 

 Fruit dry ; petals hooded and long-clawed ; stigmas 3. 2. CEANOTHUS. 



i. RHAMNUS L. BUCKTHORN. 



Leaves broadly elliptic or ovate ; flowers solitary in the axils ; carpels 3 or 4. 



i. R. cathartica. 

 Leaves lanceolate ; flowers 2 or 3 in each axil ; carpels 2. 2. R. Smithii. 



1. Rhamnus cathartica L. Cultivated for hedges and escaped; native of 

 Europe. Ft. Collins. 



2. Rhamnus Smithii Greene. Along streams in Colo, and N. Mex. Alt. 

 about 7000 ft. Pagosa Springs. 



2. CEANOTHUS L. NEW JERSEY TEA. 



Leaf-blades rounded-oval, often cordate at the base, very shining above ; closely 



glandular-dentate. i. C. velutinus. 



Leaf-blades oblong to elliptic or ovate, glandular-serrate or sub-entire. 



