AMERICAN VARIETIES OF SWEET POTATOES. 5 



soil selected has ranged from sand to a fine sandy loam. Most of the 

 studies have been made from the crops grown at Washington, but the 

 varieties have also been grown at Baton Rouge, La., Florence, S. C, 

 Norfolk, Va., Columbus, Ohio, and Watson, N. Y., for the purpose 

 of studying their behavior under different environments. The varie- 

 tal descriptions were checked with the collections grown at all of 

 the points mentioned. 



During the years the work has been in progress it has been the aim 

 to test all varieties that are grown in the United States. New varie- 

 ties have been added from time to time, and many so-called new varie- 

 ties have been grown, only to find that they were old varieties given 

 new names. It is believed that practically all varieties now grown 

 in the United States are included in the present collection. All the 

 important sweet-potato growing regions have been visited by those 

 engaged in the work, and wherever a variety was found which was 

 not 'definitely known it was added to the collection for study and 

 comparison with the varieties being grown in the test. 



Before attempting to classify the varieties of sweet potatoes, care- 

 ful descriptions were made of all varieties. Those showing a marked 

 similarity were grouped together in the field for further compari- 

 son. It has been found that all the varieties that have been grown 

 can be placed in eight well-defined groups, each group being distinct 

 and easily recognized. By means of a simple key, the group to 

 which any variety belongs can be determined very easily and quickly. 

 Each group has been given the name of the most widely known variety 

 or the variety that is most typical of that group. Three of the large 

 groups have been divided into sections to simplify the procedure of 

 identification. It is believed that this grouping of varieties makes 

 identification comparatively easy. After determining the group to 

 which a variety belongs by means of the key the group description 

 should be read to determine the section and the variety. To make 

 sure of the correctness of identification, the descriptions of all varie- 

 ties in the group should be read. 



As indicated in previous pages, no one character can be depended 

 on to establish the identity of any sweet-potato variety ; but rather 

 a combination of characters, such as the length and character of the 

 vines and the size, shape, and color of the roots. While typical 

 specimens of such varieties as the Porto Rico, Big-Stem Jersey, 

 Nancy Hall, Triumph, Yellow Strasburg, Southern Queen, and 

 Pumpkin may be described as fusiform to globular, long fusiform, 

 fusiform, medium to long cylindrical, globular, or ovoid in shape, 

 an inspection of Plates I, II, and III, which show the variation in 

 the size and the shape of several specimens of each of these varieties, 

 will show how great the variations in size and shape within the 

 variety really are. 



