2 BULLETIN 172, U. S. DEPARTMENT OF AGElCULTtTRE. 
botanical affinities of a given variety is therefore a matter of much 
importance to both the nurseryman and orchardist, and for this 
reason the attempt has been made to identify each variety with its 
species. This has been done either by a study of material or by 
means of such descriptions as exist in horticultural literature in- the 
case of varieties no longer known to be in cultivation or of which it 
has been impracticable for any other reason to secure material. 
These pages also constitute a record of achievement in American 
pomology with a fruit the importance of which was long overlooked 
and the value of which, even at the present time, is recognized by 
comparatively few. Information is brought together concerning the 
parentage when known, and a record is made of the work of those who 
have concerned themselves with the improvement of this fruit. 
With few fruits is there an equal opportunity to record step by step 
the advance which has been made since the original of the first-named 
variety was brought from its wild thicket and planted in a garden. 
GEOGRAPHICAL ORIGIN OF VARIETIES. 
The varieties of native plums have mainly originated in the Missis- 
sippi Valley, the State of Iowa alone having furnished 175, while 74 
have come from Minnesota and 44 from South Dakota. Among the 
Southern States a much larger number, 97, have originated in Texas 
than in all of the others combined. In most of the States, too, the 
varieties originated have been from the species native to the region. 
In Iowa, for instance, 138 belong to Prunus americana, leaving a 
comparatively small number belonging to species not native to the 
State. In Texas, also, three-fourths of the total number are either 
of the species growing within the State or hybrids one of the parents 
of which is native to the State. It is in these western and southern 
regions that the fruit of several of the species appears to reach its 
greatest perfection in the wild condition, and doubtless the greatest 
development under cultivation may be expected to take place here 
also. 
The geographical origin of the different varieties is indicated more 
clearly in Table I, which is designed to show the number of varieties 
belonging to a given species that have originated in each State. The 
varieties originating from subspecies are included with the species, 
but the hybrids are given separately. 
