ANACARDIACE.E. (CASHEW FAMILY.) 49 



1. ACER, Tourn. MAPLE. 



Calyx colored, usually 5-lobed. Petals as many or none. Stamens 3 to 12, 

 usually 8, inserted with the petals upon a lobed disk. Fruit divaricately 

 2-winged above, separable at maturity, each 1-seeded. Flowers in umbel- 

 like corymbs or fascicles. 



1 . A. grandidentatum, Nutt. Leaves cordate or truncate at base, rather 

 deeply 3-lobed, with broad round sinuses ; lobes rather acute, coarsely sinuate- 

 dentate : the umbel-like corymb nearly sessile, few-flowered, the pedicels long 

 and nodding. Utah and northward along the western slopes of the moun- 

 tains. Rarely attains a foot in diameter and 30 to 40 feet in height. 



2. A. glabrum, Torr. Shrub 6 to 10 feet high : leaves subreniform, orbicu- 

 lar in outline, 3-lobed or more usually 3-parted ; segments short and broad, 

 acutely incised and toothed, somewhat 3-lobed, middle one cuneate : the umbel- 

 like corymb pedunculate: sepals about 8. Includes A. tripartitum, Nutt. 

 From New Mexico to Wyoming and westward. Along water-courses among 

 the mountains. 



2. WE GUN DO, Mcench. BOX-ELDER. 



Petals and disk none. Fruit as in Acer. Sterile flowers on clustered 

 capillary pedicels, the fertile in drooping racemes. 



1. N. aceroides, Moench. Leaflets very veiny, ovate, pointed, toothed : 

 fruit smooth, with large rather incurved wings. In the valleys from New 

 Mexico northward. A tree with light green twigs and delicate drooping 

 clusters of greenish flowers a little earlier than the leaves. 



ORDER 24. ANACARDIACE^. (CASHEW FAMILY.) 



Shrubs or trees with a resinous juice, alternate leaves without stipules, 

 and small regular flowers commonly polygamous or dioecious. Stamens 

 as many or twice as many as the petals. The free ovary 1-celled and 

 1-ovuled, but the styles often 3. Fruit a dry drupe. 



1. RHTJS, L. SUMACH.^ 



Sepals and petals usually 5. Stamens inserted under the edge of a disk 

 lining the base of the calyx. Leaves simple or pinnate. 



* Leaflets 11 to 31 : flowers in a terminal thyrsoid panicle. 



1. R glabra, L. Shrub 2 to 12 feet high: leaflets whitened beneath, 

 lanceolate-oblong, pointed, serrate : fruit globular, clothed with acid crimson 

 hairs ; the stone smooth. Colorado, Utah, Idaho, and eastward across the 

 continent. Not poisonous. 



* * Leaflets 3. 



2. R. Toxicodendron, L. Climbing by rootlets over rocks or ascending 

 trees: leaflets rhombic-ovate, rather downy beneath, variously notched, sinu- 

 ate, or cut-lobed : flowers in loose and slender axillary panicles : fruit globular, 

 glabrous, whitish or dun-colored ; the stone striate. Colorado, Utah, Wyo- 

 ming, and eastward. Poisonous to the touch. 



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