CLASSIFICATION OF ANGIOSPERMS. 



253 



ing: Qiiercus infectoria of the Mediterranean, which yields the 

 Turkish or Aleppo galls which are official (p. 646) ; Quercus 

 Robur, which is sometimes divided into Q. pubescens and Q. pe- 

 duncidata, yields a European gall; the live oak (Q. virginiana) 

 of Texas ; and Q. lobata of California. Various oaks of the South- 

 ern States also produce " ink balls " or " ink galls," as Q. coc- 



FiG. 13S. White oak (Quercus alba): A, branch with staminate flowers; 

 B, branch showing the characteristic lobed leaves. 



cinea and Q. imbricaria. Because of the high tannin content the 

 barks of several species of oak are used in the tanning industry, 

 as that of white oak (Quercus alba), red oak (Q. rubra), Spanish 

 oak (Q. digitata), and black oak (Q. velutina) all of North Amer- 

 ica; Q. pedunculata and sessiMora of. Germany, and Q. den- 

 tata of Japan. 



