Vol. X 
APRIL, 
192, 
3 
No. 4 
mmmm ^ 
AMERICAN 
OF BOTANY 
OFFICIAL PUBLICATION OF THE 
BOTANICAL SOCIETY OF AMERICA 
& 
CONTENTS 
Pectinase in the spores of Rhizopus. ..J. L. Weimer and L. L. Harter 167 
The chromosomes of-Riccardia pinguis . .. Amos M.Sho Walter 170 
Australasian botanical notes II. Victoria, South Australia, and West Australia 
Douglas H. Campbell 173 
Evolution and geographical distribution of the genus Vernonia in North America 
Henry Allan Gleason 187 
The availability of iron in nutrient solutions for wheat 
W. E. Tottingham and E. J. Rankin 203 
The effect of the hydrogen ion on the protoplasm of the root hairs of wheat 
Rut h JVIV'^ADijo^s •,211; 
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E ntered as second-class matter February 21,1914, at the post office at Lancaster, Pa., under the act of March 3,1879 
