107 



fluent with the midvein before branching off. After leaving it 

 they branch upward in the manner described, though they some- 

 times fork (Fig. 8). 



Besides the larger secondaries described above, there also 

 extend from the midrib a number of smaller ones that may be 

 classed with the tertiaries, as they usually connect with them. 



Figure 8. Leaf showing forked secondary. 



It often happens, though, especially when there is a particularly 

 large gap between any secondary and the one next succeeding 

 it, that one of these smaller veins is so strongly developed that 

 it takes the place of a larger one. They may, however, be easily 

 distinguished from the others by the fact that they do not extend 

 out far enough to form a part of the regular secondary system. 

 Connecting the secondaries with each other is a series of ter- 

 tiaries which are much smaller than the veins just considered and 

 which tend to form oblong or quadrangular areolae. Usually, 

 they are rather uniform in size, but they often vary, particularly 



