80 



Species Hybrids of. Digitalis 



that each follows the maternal type. The upper surfaces of the leaves 

 show similar peculiarities. 



That the above differences are due not merely to degree of pro- 

 minence of the veins but also to a dissimilar system of venation may 

 be seen from text-figs. 22 — 25. 



25 

 DQxDP 



Figs. 22—25. 



These are camera lucida dravs^ings of leaves bleached in Mayer's 

 solution, stained in safranin and afterwards cleared and mounted in 

 Canada balsam. In D.P. there is a network system of large veins, 

 whilst very fine veins fill up the meshes of this network. In D.G., on 

 the other hand, the only large veins are the midrib and a few longi- 

 tudinally running laterals (which are much smaller than the large veins 

 of D.P.) — the rest of the system consisting entirely of veins all of much 



