Periodical Literature. 729 



in the two situations than through the cooHng effects of descend- 

 ing and warming effects of ascending currents. 



The Plant Geography of North Central New Mexico. Botanical 

 Gazette- September, 1912. Pp. 194-217. 



BOTANY AND ZOOLOGY. 



To our small amount of knowledge in re- 

 Anatomy gard to the actual differences in structure 



of of the same species growing in different 



Plants habitats, Miss Starr has made an important 



from contribution. The material of the study 



Different was taken from the sand dunes of Lake 



Sites. Michigan in Indiana and from the flood 



plains of the Des Plaines river. The leaves 

 were compared with respect to thickness, and the relative pro- 

 portion which each of the tissues bears to the entire thickness; 

 the stems with respect to number of vessels in an octant, the 

 average diameter of the larger vessels, the thickness of the walls 

 of the vessels, the thickness of the walls of the fibers, the number 

 of growth rings and the thickness of the cork. Tables of the 

 various species show these points in actual measurement and in 

 percentages. 



The summary of the observations is given below, where X and 

 M refer respectively to the xerophytic and the mesophytic habitat, 

 the numbers preceding the number of species in which the charac- 

 ter occurred. 



Hairs more abundant, 12 X — o M (3 same) 



Surface of epidermal cells greater, 9 X — 5 M (2 same) 



Depth of epidermal cells greater, 5 X — 12 M (4 same) 



Outer wall of epidermis heavier, 18 X — o M (2 same) 



Cuticle ridged, 10 X — 6 M 



Palisade more completely organized, 17 X — o M (i same) 

 Better development of conductive elements, 15 X — 2 M (i same) 



Heavier sclerenchyma, 14 X — i M (i same) 



Heavier collenchyma, 17 X — o M 



