266 BOTANICAL GAZETTE [octob 



the coast, the ecological factors, and the plant associations. It was 

 his intention to enter into an investigation of the anatomical rela- 

 tions of the plants described, but other work prevented. In the 

 fall of 1908 he suggested that I undertake the study, and it has been 

 under his direction that the work has been carried on. I wish to 



him and to all the members 



me with criticism 



those who aided me 



HOLTZMAN 



access to his paper. 



my 



from the vicinitv of Miller 



from the Indiana dunes, chiefly 



p Part nr\c\ Fiirnessville. The 



mesophytic forms came mainly from the flood plains of the 

 Desplaines River at Riverside; some were collected in other meso- 



came from 



Mississipp 



formalin 



microtome. The leaves that made 



most successful permanent preparations were killed with corrosive 

 sublimate dissolved in 95 per cent alcohol, used hot. These were 

 easily sectioned in paraffin. I found 8 /x the most satisfactory 

 thickness. Free-hand sections were also made. Safranin and 



in stammer, lhe names 



Gray's Manual and differ therefore at times 



from those 



made 



half in reproduction. 



magnified 



Ecological factors in the dunes 



Light and heat.— There is direct illumination, increased by 

 ection from the sand. Because of the scanty vegetation and the 

 at exposure, the temperature of the air is higher in summer and 



s. Owing to the 



than 



high conductivity of sand, the same great diverj 

 extremes is present in the temperature of the soil. 



Wind.— Cowles considers this the most potent factor in 

 determining the character of the dune vegetation. The winds 



