Vol. XIV Washington, D. C., August 5,1918 No. 6 
ANATOMY OF THE POTATO PLANT, WITH SPECIAL 
REFERENCE TO THE ONTOGENY OF THE VASCULAR 
SYSTEM 1 
By Ernst F. Artschwager 
Agent, Cotton , Truck , and Forage Crop Disease Investigations , Bureau of Plant 
Industry, United States Department of Agriculture 
COOPERATIVE INVESTIGATIONS BETWEEN THE BUREAU OF PLANT INDUSTRY 
OF THE UNITED STATES DEPARTMENT OF AGRICULTURE AND THE AGRICUL¬ 
TURAL EXPERIMENT STATION AT CORNELL UNIVERSITY 
INTRODUCTION 
Recent studies of potato diseases have made it obvious that more 
accurate knowledge regarding the normal structure of potato plants 
(Solarium tuberosum) is necessary. The present work was undertaken in 
order to obtain data which may make possible a more rapid progress in 
the investigation of several important potato diseases, such as the potato 
leafroll. This disease, which is a serious one, was the main reason for 
undertaking the present detail study. It was the original intention of 
the writer to investigate the pathological anatomy of plants suffering 
from leafroll, but because of the lack of adequate information regarding 
their normal structure no information for comparative purposes was 
available. 
The anatomy and development of the potato plant have been studied 
up to this time chiefly from the viewpoint of economic botany; conse¬ 
quently previous work relates largely to observations on gross morphol¬ 
ogy. A study of the origin, differentiation, and organization of the 
vascular supply, however, is essential to a clear understanding of the 
physiology of the organs and of the relation of this supply to tuber 
formation. Furthermore, such a study enables us to distinguish the 
significant points in all pathological changes. 
The critical study of the internal anatomy of plants began only in the 
middle of the last century, when the work of Schleiden and other investi¬ 
gators raised botany to the level of other sciences. Schleiden, in his 
1 This work was begun in the field laboratory of the Office of Cotton, Truck, and Forage Crop Disease 
Investigations at Greeley, Colo., in the summer of 1916, and was continued in the Department of Plant 
Pathology at Cornell University under the direction of Prof. H. H. Whetzel and Dr, H. A. Edson, to whom 
the author wishes to express his gratitude for their courtesy and helpful suggestions. To Dr. A. J. Eames, 
of the Department of Botany, Cornell University, the writer is especially indebted for the constant advice 
and criticism received in preparation of materials, interpretation of slides, and editing of the paper. Thanks 
are also due to Mr. W. R. Fisher for accurate and painstaking work in the preparation of the photographs. 
Journal of Agricultural Research, 
Washington, D. C. 
op 
Vol. XIV, No. 6 
Aug. 5, 1918 
Key No. G-150 
(221) 
