158 ANACARDIACEAE 



the flowers, which appear in June or July, are greenish yellow. 

 The fruit matures from late August into October, and is 

 slightly flattened, asymmetrically globose, bright red, densely 

 covered with short, sticky hairs, and sour. The smooth seeds 

 are small, ash colored or light brown, and somewhat wider 

 than long. 



Distribution. — The Smooth Sumac grows in dry, sandy or 

 gravelly soil and ranges from Nova Scotia west to North Da- 

 kota and south to Florida and Louisiana. It often grows in 

 colonies in open places, on sandy or gravelly ridges, along the 

 borders of woods, and on fence rows. It is distributed through- 

 out the state of Illinois. 



RHUS VERNIX Linnaeus 

 Poison Sumac Swamp Sumac Poison Elder 



The Poison Sumac, fig. 37, is an erect shrub, or sometimes a 

 small tree, with a widely spreading crown of smooth branches 

 and branchlets bearing compound leaves 6 to 14 inches long. 

 The leaf rachis is smooth or nearly so, and the leaflets, of which 

 there are 7 to 13, vary greatly in shape and size on the same 

 leaf, being obovate-oblong to oval, and \]/2 to 4]/2 inches long by 

 ^ to 2 inches wide. They taper abruptly to a blunt point and 

 also taper to the petiole. They may be nearly sessile or stand 

 on short stalks, the terminal leaflets being longer stalked, as a 

 rule, than the others. The margins are entire or somewhat 

 undulating, and at maturity the leaves are dark green and 

 smooth above ; when young they are pubescent but soon become 

 smooth or nearly so beneath. 



The inflorescence takes the form of an axillary panicle. The 

 flowers open in June and are greenish yellow. The fruit, which 

 matures in August and September, is pale green to almost color- 

 less and slightly flattened to somewhat asymmetrically globose. 

 The flat, depressed seeds are deeply grooved along the sides and 

 have about 4 ridges on a side. 



Distribution. — The Poison Sumac is a shrub that grows on 

 low ground about lakes and tamarack bogs. In such situations 

 it ranges from northern New England to Minnesota and south 

 to Florida and Texas. In Illinois, it is known only in the 

 tamarack bogs of Lake County. 



Poison Sumac is the most poisonous shrub in Illinois. Its 



