UNITED STATES DEPARTMENT OF AGRICULTURE 
jfc BULLETIN No. 1021 
-^Jk^^^lf f.nnt rihutinn frnm (lio Hntciii nf Plant Inrtnctrv 
Contribution from the Bureau of Plant Industry 
WM. A. TAYLOR, Chief. 
XUv^wt. 
Washington, D. C. 
PROFESSIONAL PAPER 
April 17, 1922 
GROUP CLASSIFICATION AND VARIETAL DE- 
SCRIPTIONS OF AMERICAN VARIETIES OF 
SWEET POTATOES. 1 
By H. C. Thompson, formerly Horticulturist, and James H. Beattib, Horticul- 
turist, Office of Horticultural and Pomological Investigations. 
CONTENTS. 
Importance of varietal classification 
of sweet potatoes 
Early attempts al classification 
Proposed system of classification 
Key to the groups 
Descriptions of the groups 
Ticotea group _ 
Belmont group 
Spanish group 
Shanghai group 
Florida group 
Page. 
Page. 
Description of the groups — Contd. 
Southern Queen group 9 
Pumpkin group 9 
Jersey group 10 
List of varieties included in the key_ 11 
Descriptions of varieties 11 
Check list of names used in sweet- 
potato literature 18 
Bibliography of sweet-potato litera- 
ture 26 
IMPORTANCE OF VARIETAL CLASSIFICATION OF SWEET 
POTATOES. 
To those familiar with the present state of sweet-potato nomen- 
clature it is apparent that there is need for some simple system of 
classification by which varieties may be identified well enough to 
place them in the groups to which they belong. The need for such 
a classification is clearly shown by the large number of new names 
that each vear are given to old varieties. The need is also readilv 
1 Credit for the description of many of the varieties of sweet potatoes and for the 
working out of the system of classification contained in this bulletin is due F. J. Tyler, 
formerly assistant in botany of the Bureau of Plant Industry. 
The main portion of the work was done by Mr. Tyler between 1902 and 1906 ; the addi- 
tion of a number of important varieties not studied by Mr. Tyler and further work on all 
the varieties has necessitated changes in the key and in some of the descriptions. 
During the progress of these investigations considerable work has been done by W. R. 
Beattie. horticulturist ; Chester J. Hunn, assistant horticulturist ; and H. M. Conolly. 
formerly assistant horticulturist, Office of Horticultural and Pomological Investigations, 
Bureau of Plant Industry. 
71638°— 22 1 
