VACCINIACEAE 231 



There are more than 150 species in this genus, which has 

 a very wide geographic distribution. Between 15 and 20 of 

 them occur in North America. The following are the shrubby 

 species occurring in Illinois. 



Key to the Blueberry Species 



Stems more or less upright, at least not creeping or trailing; 

 fruit blue or black. 

 Shrubs usually 3 feet or more tall; leaves glossy above; fruit 



black V, arboreum, p. 231 



Shrubs commonly less than 3 feet high; leaves not conspicu- 

 ously glossy; fruit blue or blue black. 

 Leaves glabrous beneath at maturity. 



Lower surface of leaves green, margin serrulate 



V. angustifolium, p. 232 



Leaves glaucous beneath, the margin entire 



V. vacillans, p. 232 



Leaves pubescent beneath at maturity V. canadense, p. 233 



Stems trailing or creeping; fruit reddish. 



Bracts placed above the middle of the pedicel, green 



V. macrocarpum, p. 235 



Bracts generally placed below the middle of the pedicel, 



mostly colored V. Oxycoccus, p. 236 



VACCINIUM ARBOREUM Marshall 

 Farkleberry 



The Farkleberry, fig. 60, is a shrub up to 10 feet high with 

 straggling stems as much as 2 inches in diameter, which are 

 covered with scaly, gray bark and bear green branchlets, which 

 become gray or brown but remain more or less pubescent. 

 The leaves stand on very short petioles and are obovate to 

 nearly circular and up to 21/^ inches long by 11/ inches wide. 

 The margins are revolute and entire and usually bear large, 

 sessile glands. The blade is acute or rounded, mucronate 

 tipped at the apex and narrowed at the base, glabrous and 

 shiny above and pale and more or less pubescent beneath. 

 There often are sessile glands on the midrib and veins be- 

 neath. 



The white flowers, which appear from late in May until 

 mid June, are borne in axillary or, frequently, in terminal 

 p racemes composed of many flowers. Fruit matures in October 

 or later as a black, globose, shiny, dry and inedible berry, 

 which contains many seeds covered on the surface with shal- 

 low pits. 



