SUMACH FAMILY 551 



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

 densely pilose; calj^x-Iobes 1.5 mm. long; petals yellowish, 3 mm. long; fruits 

 4 mm. wide. R, glabra occidentalis Torr. R, arguta Greene. R. niiens Greene 

 Along streams : Ore.— B.C.— :\Iont.— Utah. Son, My-JL 



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

 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 above, 

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

 obovate, the terminal one cuneate-spatulate, usually more or less 3-Iobed 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. subpinnata, and S, glabrata Greene. Hills and plains: Sask.— Mo,— Tex.— 

 Cahf. — Wash. Plain — Submont. Ap-Je. 



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



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



rather thin, roimded-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 

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

 regions: Utah— Ariz.— L. Cahf. 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-ceIled; 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 3 mm. long. 1. r. kydbergii. 



l^eaflets thin, 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. hesperinum 

 Greene, a large form. Hillsides and open woods: S.D. — Ivans. — 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. SubmonL Je. 



Family 78. ACERACEAE. Maple Family. 



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

 ules. Flowers perfect or polj'gamous, rarely dioecious or monoecious, 

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



