SUMACH FAMILY 551 



cous beneath; panicles 1-2 dm. long, branches usually strongly ascending, rather 

 densely pilose; calyx-lobes 1.5 mm. long; petals yellowish, 3 mm. long; fruits 

 4 mm. wide. R. glabra occidenlalis Torr. R. arguta Greene. R. nitens Greene. 

 Along streams: Ore. — B.C. — Mont. — Utah. Son. My-Jl. 



3. R. Osterhoutii Rydb. Shrub about 1 m. high; leaves trifoliolate; 

 leaflets sessile, 1-2.5 cm. long, cuneate, 3-5-lobed and some of the lobes with 

 rounded teeth, dark green above, pale beneath. Schmaltzia pubescens Osterh. 

 Hills: Colo. Submont. Je. 



4. R. trilobata Nutt. Shrub 1-2 m. high, blooming before the leaves; 

 leaves trifoliolate, with unpleasant odor; leaflets 1-3 cm. long, dark green abovsi 

 paler and minutely pubescent beneath, the lateral ones elliptic or cuneate- 

 obovate, the terminal one cuneate-spatulate, usually more or less 3-lobed and 

 crenate; petals obovate, 2 mm. long; fruit globose, 5-6 mm. thick, more or less 

 densely short-pubescent. Schmaltzia trilobata, S. Bakeri, S. cognata, S. glomerata, 

 S. subpinnala, and S. glabrata Greene. Hills and plains: Sask. — Mo. — Tex. — 

 Calif. — Wash. Plain — Submont. Ajj-Je. 



5. R. oxyacanthoides (Greene) Rydb. Low shrub, about 1 m. high; leaves 

 3-fohoIate; leaflets obovate-cuneate, or the terminal one rhombic-obovate, 

 rather thin, rounded-crenate, the terminal one 2-4 cm. long, and often 3-lobed, 

 the lateral ones 1.5-3 cm. long; fruit bright red, puberulent. Schmaltzia oxy- 

 acanthoides Greene. Hills and canons: w Colo. — Utah— (? Mont.) Submont. 

 Ap-My. 



6. R. utahensis Goodding. A shrub 1-1.5 m. high, diffusely branched; 

 leaves simple, the blades usually suborbicular or reniform, truncate at the base, 

 crenate, or rarely 3-lobed, 1.5-3 cm. long, finely pubescent beneath; inflorescence 

 few-flowered; fruit rather large, 5-8 mm. thick, short-pubescent. R. canadensis 

 simplicifolia Greene. Schmaltzia simplicifolia and S. affinis Greene. Desert 

 regions: Utah — Ariz. — L. CaUf. Son. Ap. 



2. TOXICODENDRON (Tourn.) Mill. Poison Ivy, Poison Oak, 



Poison Sumach. 



Shrubs, trees, or vines, with a resinous sap, poisonous to touch. Leaves 

 alternate, pinnately 3-several-foliolate, with coarsely toothed or entire leaflets. 

 Flowers polygamous, paniculate. Sepals 4-6, persistent. Petals 4-6, imbricate, 

 yellowish or greenish. Disk annular. Stamens 4-6 or 10. Ovary 1-celled; ovules 

 pendulous. Drupe whitish, smooth, shining, glabrous. Stone striately ribbed. 



Leaflets thick, the terminal one decidedly longer than broad, its petiolule usually 1-2 cm. 



long; petals ;i mm. long. 1. T. Rydbergii. 



Leaflets tliin, the terminal one nearly as broad as long, its petiolule 3-4 cm. long; petals 



2.5 mm. long. 2. T. longipcs. 



1. T. Rydbergii (Small) Greene. A single-stemmed shrub, usually less than 

 1 m. high; leaves pinnately 3-foliolate; leaflets 3-10 cm. long, rhombic-ovate, 

 thick, bright green, strongly veined beneath, glabrous, usually coarsely and 

 broadly toothed; flowers in dense axillary panicles; petals whitish yellow, with 

 greenish veins; fruit depressed-globose, 5-6 mm. in diameter. T. hesperinu/n 

 Greene, a large form. Hillsides and open woods: S.D. — Kans. — N.M. — Ariz. — 

 Ore.^B.C. Plain — Submont. Je-Jl. 



2. T. longipes Greene. Erect single-stemmed shrub; leaves pinnately 3- 

 foliolate; leaflets thin, light green, the lateral ones broadly obliquely ovate, 7-10 

 cm. long, the terminal one almost orbicular, abruptly short-acuminate, coarsely 

 toothed; inflorescence racemose, lax, rarely with 1 or 2 branches below; petals 

 reflexed, greenish white, with dark veins. Canons: Utah. Submont. Je. 



Family 78. ACERACEAE. Maple Family. 



Shrubs or trees, with opposite, simple or compound leaves, without stip- 

 ules. Flowers perfect or polygamous, rarely dioecious or monoecious, 

 regular. Sepals 4 or 5, rarely 6-9, imbricate, often colored. Petals of the 



