ANACARDIACEAE 



Staghorn Sumac 

 Rhus typhina Torner 



HABIT. A shrub or small tree to 40 feet high and I foot in 

 diameter; commonly in broad thickets. 



LEAVES. Alternate; deciduous; pinnately compound with 

 11-31 oblong, glabrous, serrate, dark green leaflets each 2-5 

 inches long. 



FLOWERS. Regular; dioecious or polygamous; small; green- 

 white; in dense, hairy panicles 6-12 inches long; after the leaves. 



FRUIT. Compact, conelike clusters of red, hairy drupes, 

 each V4 inch. 



TWIGS. Thick; velvety-hairy; milky juice; thick pith. Win- 

 ter buds: terminal absent, lateral K inch long, conical, brown, 

 silky hairy. 



BARK. Thin; dark brown; smooth, becoming scaly with age. 



WOOD. Unimportant; soft and weak; ring-porous; orange- 

 colored. 



SILVICAL CHARACTERS. Intolerant; fast-growing; short- 

 lived. 



About 17 species are native to North America with 9 rarely reaching 

 tree size and keyed out below. Two species, poisonous to the touch, are 

 placed either in the genus Rhus or Toxicodendron; these are poison- 

 sumac, T. vernix (L.) Ktze. and poison ivy or oak, T. radicans (L.) Ktze. 

 1. Leaves simple or rarely 3-foliolate, leathery, evergreen. 



2. Leaves broadly ovate, entire; flowers in dense spikes; fruit red; 



California and Arizona R. ovata S. Wats., Sugar Sumac 



2. Leaves oval to ovate, rounded at apex. 



3. Fruit white in branched panicles; southern California 



R. laurina Xutt., Laurel Sumac 



3. Fruit red. 



4. Leaves toothed or entire; southern coastal California 



R. integrifolia (Nutt.) B. & H., Mahogany Sumac 



4. Leaves entire; Yuma County, Arizona 



R. kearneyi Bark., Kearney Sumac 



1 . Leaves pinnately compound, deciduous. 



5. Flowers in dense, terminal panicles; friut red, hairy. 



6. Twigs and petioles velvety-hairy 



R. typhina Torn., Staghorn Sumac 



6. Twigs and petioles glabrous or hairy. 



7. Rachis terete; twigs glabrous and glaucous; leaves serrate; 



most of North America R. glabra L., Smooth Sumac 



7. Rachis winged; twigs pubescent; leaves nearly entire. 



8. Leaflets ovate-lanceolate; New Hampshire to Michigan 



and Kansas, south to Georgia and Texas 



R. copallina L., Shining Sumac 



8. Leaflets narrow-lanceolate, often falcate; south Oklahoma 



to Texas and New ISIexico 



R. lanceolata Britt., Prairie Shining Sumac 



5. Flowers not numerous in terminal or axillary panicles. 



9. Fruit red ; rachis winged; leaves less than 1 inch long; west Texas 



to Arizona R. microphylla Engelm., Littleleaf Sumac 



9. Fruit white; rachis terete; leaves H-2 H inches long; Quebec 



to Minnesota, south to Gulf 



R. (or r.) vernix (L.) Ktze., Poison Sumac 



[289] 



