=A.= Twigs downy; rachis wing-margined; leaflets entire or nearly so 3. =A.= Twigs smooth. (=B.=) =B.= Rachis of leaf broadly winged; leaflets serrate 5. =B.= Rachis not winged. (=C.=) =C.= Leaflets 11 to 31, serrate; fruit hairy 2. =C.= Leaflets 7 to 13, entire; fruit smooth; poisonous 4. * Leaves twice-pinnate; variety under 2. [Illustration: R. týphina.] 1. =Rhús týphina=, L. (STAG-HORN SUMAC.) Leaflets 11 to 31, oblong-lanceolate, pointed, serrate (rarely laciniate), pale beneath. Branches and footstalks densely hairy. Fruit globular, in large, dense, erect panicles, covered with crimson hairs. Shrub or tree, 10 to 30 ft. high. It is very common along fences and on hillsides. The wood is orange-colored and brittle. [Illustration: R. glàbra.] 2. =Rhús glàbra=, L. (SMOOTH SUMAC.) Leaflets 11 to 31, lanceolate-oblong, pointed, serrate, smooth, glaucous white beneath. Branches not hairy. Fruit globular, in a rather open, spreading cluster, covered densely with crimson hairs. A shrubby plant, 2 to 12 ft. high, found quite abundantly in rocky or barren soil throughout. [Illustration: R. laciniàta.] Var. _laciniata_ is frequently planted for ornament. It has very irregularly twice-pinnate leaves drooping gracefully from the branches. [Illustration: R. copallìna.] 3. =Rhús copallìna=, L. (DWARF MOUNTAIN SUMAC.) Branches and stalks downy; leafstalk wing-margined between the 9 to 21 oblong-lanceolate, usually entire leaflets, which are oblique at base and smooth and shining above. Wild in rocky hills throughout; often cultivated. North, a beautiful shrub; south, a tree. 2 to 25 ft. high. [Illustration: R. venenàta.] 4. =Rhús venenàta=, DC. (POISON-SUMAC. POISON-DOGWOOD. POISON-ELDER.) Leaflets 7 to 13, obovate-oblong, entire, abruptly pointed, smooth or nearly so. Fruit small, globular, smooth, dun-colored, in loose axillary panicles hanging on late in winter; the stone striate. This is a very poisonous species (to the touch), 6 to 18 ft. high, growing in swamps. Rarely at all tree-like. [Illustration: R. Osbéckii.] 5. =Rhús Osbéckii=, DC. (CHINESE SUMAC.) Leaves very large, pinnate, assuming in autumn a rich reddish-fawn or orange color; the leafstalk broadly winged between the leaflets; leaflets serrate. A small ornamental tree, 10 to 25 ft. high; cultivated; from China; quite hardy in the Northern States. [Illustration: R. Cótinus.]