ANACARDIACEAE 159 



poisonous principle is the same as that carried by Poison Ivy, 

 but the effect is reputed to be much more severe. 



RHUS AROMATICA Alton 

 Fragrant Sumac 



The Fragrant Sumac, fig. 38, is a low, spreading shrub about 

 3 feet high or, rarely, an erect shrub up to 12 feet high, with 

 smooth or pubescent branchlets, compound leaves 2 to 5 inches 

 long, and petioles from 1/^ to 1]4 inches long. There are 3 

 ovate to rhombic leaflets per leaf, the lateral 2 sessile, the 

 terminal on a short stalk. The terminal leaflet is l]/^ to 3^ 

 inches long and about ^^ to 2l/^ inches wide, and the lateral 

 leaflets are about three-fourths as large. The blades are acute 

 or rounded at the apex, the terminal one narrowed at the base 

 and the lateral ones either narrowed or rounded and asym- 

 metrical at the base. The margin is closely crenate-dentate, 

 and the surface is pubescent both above and beneath, or some- 

 times glabrous. 



The inflorescences are in the form of short, crowded, axillary 

 spikes borne on year-old branchlets. The greenish-yellow flowers 

 open, as a rule, before the leaves appear. The fruit, which 

 matures from July on into September, is red, densely hairy, 

 globose, and small, and contains a light brown, slightly flat- 

 tened, asymmetrical seed. 



Distribution. — The Fragrant Sumac prefers ridges and 

 rocky bluffs along streams and ravines, w^here open situations 

 favor its growth. In such habitats, it is distributed from 

 western Vermont to Minnesota and south to Florida and 

 Louisiana. It grows in suitable situations throughout Illinois. 

 When erect and with leaflets rounded to obtuse at the apex, 

 more densely pubescent beneath than above, and provided with 

 fewer, rounded teeth, shrubs of this species are segregated as 

 var. illinoensis (Greene) Rehder. 



RHUS RADICANS Linnaeus 



Poison ivy Three-Leaved Ivy Poison Oak 



Poison Ivy, fig. 38, is a trailing shrub or climbing vine which 

 trails by underground stems or climbs by aerial rootlets. Its 

 branches are more or less striate and pubescent. The com- 



