CORNACEAE 213 



There are about 20 poorly understood species of dogwoods, 

 most of them natives of the north temperate zone. The fol- 

 lowing occur in Illinois. 



Key to the Dogwood Species 



Pubescence on young twigs, inflorescence and leaves woolly and 

 more or less spreading. 

 Leaves rough on upper surface, branchlets brown, fruit 



white C. asperifolia, p. 214 



Leaves not rough to the touch on the upper surface. 



Leaves roundly ovate, with 7 to 9 pairs of veins, branch- 

 lets greenish, fruit blue C. rugosa, p. 213 



Leaves ovate or elliptic, with 4 to 6 pairs of veins. 



Branchlets purplish, fruit blue C. Amomum, p. 214 



Branchlets brown, fruit white C. Baileyi, p. 216 



Pubescence either none or, if present, entirely appressed on the 

 leaves, inflorescence and young twigs. 

 Leaves opposite, fruit white. 



Leaves broadly ovate, branches red C. stolonifera, p. 217 



Leaves lanceolate, branches gray C. foemina, p. 219 



Leaves alternate, fruit blue C alternifolia, p. 219 



CORNUS RUGOSA Lamarck 

 Roundleaf Dogwood 



The Roundleaf Dogw-ood, fig. 56, is an erect shrub 6 to 10 

 feet high, with gray or brownish-green branches and green 

 branchlets which may be nearly smooth, partly pubescent, or 

 even woolly pubescent. The opposite leaves are nearly circular 

 to broadly ovate, and variable in size, being at times 6 inches 

 long. The blade is abruptly narrowed at the tip to a short 

 point and rounded or, rarely, narrowed at the base. It is 

 short-pubescent with appressed hairs above and pale and 

 woolly beneath. The veins are arranged in 7 to 9 pairs, and 

 the petioles are short, commonly about ^4 i"ch in length. 



The flowers appear from late in May until about the middle 

 of June, and the fruit, which matures in autumn, is globose, 

 blue, and contains a globose stone which is rounded at each 

 end, somewhat oblique, and marked with 8 shallow, length- 

 wise furrows. 



Distribution. — The Roundleaf Dogwood, which prefers 

 sandy habitats, ranges from Nova Scotia to Manitoba and south 

 to Virginia and Iowa. In Illinois, it is abundant chiefly on 

 the sands near Lake Michigan, but it has been reliably re- 



