ACERACEAE. 
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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. 
1. 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. 
1. Rhamnus. 
Fruit dry; petals hooded and long-clawed; stigmas 3. 2. Ceanothus. 
1. RHAMNUS L. Buckthorn. 
Leaves broadly elliptic or ovate ; flowers solitary in the axils ; carpels 3 or 4. 
1. 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. 1. C. velutinus. 
Leaf-blades oblong to elliptic or ovate, glandular-serrate or sub-entire. 
