2 BULLETIN" 1021, U. S. DEPARTMENT OF AGRICULTURE. 



seen from a study of the literature on sweet potatoes. There being 

 no recognized system of classification, the investigator uses a local 

 name or the name under which the sweet potato was received. In 

 either case the name may be entirely misleading or may have no 

 significance. 



While several hundred names are given to varieties of sweet po- 

 tatoes grown in the United States, there are not over 40 true varie- 

 ties. Not more than 10 of these varieties are of commercial impor- 

 tance, and 4 of them constitute the bulk of the commercial crop. 

 Some of the important varieties are known under many different 

 names. The Southern Queen, for exanrple, is known under at least 

 20 different names, although Southern Queen and Hayman are by far 

 the most common. Probably 90 per cent of the growers of this va- 

 riety know it under one of the two names mentioned. Even such a 

 well-known variety as Yellow Jersey is known under at least 10 

 names. 



Giving new names to old varieties is very common, but is very 

 confusing. In many cases the giving of a new name to an old variety 

 is done because the true name is not known, but in other cases the 

 new name is given for the purpose of deception. When a grower 

 receives a sweet potato which is not known to him, he should make 

 every effort to learn the correct name and not give it a name of his 

 own choosing. There is certainly no excuse for renaming such well- 

 known varieties as Southern Queen and Yellow Jersey, but it is the 

 best-known varieties that have the greatest number of names. 



To set forth a simple system of classification of sweet-potato vari- 

 eties that will be of help to investigators, teachers, and growers is the 

 purpose of this bulletin. 



EARLY ATTEMPTS AT CLASSIFICATION. 



The earliest important attempt at classifying the varieties of sweet 

 potatoes was made by R. H. Price ( 55 ), x of the Texas Agricultural 

 Experiment Station. Under this system sweet potatoes are classified 

 into three groups based on the shape of the leaves, as follows : 



(1) Varieties with entire or round foliage. 



(2) Varieties with shouldered foliage. 



(3) Varieties with deeply cut or lobed foliage. 



After classifying sweet potatoes into the three groups by the 

 typical shape of the leaves, each variety is described separately, but as 

 no key is given except that referring to the shape of the leaves, it is 

 not possible to determine a variety if the name is doubtful or un- 

 known. The procedure to follow under this system is first to deter- 



1 The serial numbers in parentheses refer to the " Bibliography of sweet-potato litera- 

 ture " at the end of this bulletin. 



