CLASSIFICATIOX OF ANGIOSPERMS. 



253 



ing 



Quercus infectoria of the Mediterranean, which yields the 

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

 Rohiir. which is sometimes divided into 0. pubescens and Q. pe- 

 dnnculata, yields a European gall; the live oak (0. 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. 135. White oak {Quercus alba): A, characteristic, lobed leaf; B, young branch 

 showing pistillate (p) and staminate (s) flowers; C. hairy bracts of a staminate flower; D. 

 group of hairs from bract; E, stamen; F. pollen grains; G, cluster of pistillate flowers; H, 

 acorn with cupule; I, starch grains from acorn, which vary from lo to 25 ij. long; J, trans- 

 verse section of bark showing cork (k). stone cells (st), bast fibers (b). crystal fibers (ca), 

 medullary rays (m). parenchyma (p) ; K, longitudinal section of bark showing end of bast 

 fiber (b) crystal fibers (ca) and parenchyma cells (t) containing tannin. 



ciiiea and Q. imbricaria. Several species of oak are used in the 

 tanning industry, as that of white oak {Quercus alba), red oak 

 (Q. rubra), Spanish oak (O. digifata), and black oak (0. 

 velutina), all of North America: Q. pednnculata and sessilifiora 

 of Germany, and Q. dentata of Japan. 



