4 BULLETIN 1167, U. S. DEPARTMENT OF AGRICULTURE. 
of flesh ; the inner skin is commonly reddish or purple, and the flesh 
is white, pink, or purple. Most yampis are of excellent quality. The 
vine is angular and usually 2-winged. The leaves are prominently 
3-lobed. Plants of this species are not very strong growers. 
THE GREATER, OR TEN-MONTHS, YAM. 
DESCRIPTION OF THE PLANT. 
The vine of the greater yam, Dioscorea cdata, is 4- angled and has 
heart-shaped opposite leaves (PL I). As the specific name alata 
suggests, the stem is often winged (alate) at the angles; it is without 
thorns or spines. In general, the flesh of the tubers is white and the 
inner skin white or merely yellowish. There are varieties, however, 
with yellowish flesh; others have white flesh and reddish or purple 
inner skin, and some even have light or deep purple flesh. The 
quality ranges from inferior to excellent, according to variety. The 
starch granules average rather large, having about the same range in 
size as those of the white potato, but with the smaller granules fewer 
in number ; they are often somewhat triangular in outline, as viewed 
under the microscope, instead of being always oval or round as in 
the potato. 
The tubers of the largest varieties sometimes attain great size, 
100 pounds or more, especially when the climatic conditions are 
such as to permit growth without serious interruption for a season 
greater than the normal length. The greater yam is the most im- 
portant as well as the most widely distributed of the six species 
which have been mentioned. It is this yam that has been most 
widely tested in the southern United States and which has thus far 
shown the greatest adaptability for cultivation in Florida and other 
sections of the South Atlantic and Gulf regions. Besides producing 
larger tubers than the other yams, this species exists in a greater 
number of varieties. Although a long season, 8 to 10 months, is 
required for the development of a good crop, yet. in one or another 
of its varieties the greater yam is adapted to a rather wide range of 
cultural conditions. It is believed that in favorable situations some 
varieties can be successfully grown, at least for home use, in the 
coast regions from Galveston, Tex., to Charleston, S. C, and possibly 
in parts of southern California. 
HISTORY OF THE INTRODUCTION. 
Two or three varieties of the greater yam have been successfully 
cultivated on a small scale by a few persons in southern Florida for 
many years, though no data are available to show when they were 
introduced. However, the following extract from a letter written 
to the Department of Agriculture by J. DeHoff, Arch Creek, Fla., 
March 23, 1913, indicates the successful introduction of one of them 
not much later than the middle of the last century : 
I got one seed bulb in 1893. when I first came to Avon Park, De Soto 
County, Fla.. from a neighbor, H. G. Burnett, who had a few in his garden. 
He got them from his father-in-law at Fort Myers, where they have been 
grown, I understand, for 50 years, though not in large quantity. I have kept 
seed from year to year since that time (no more, though, than I wanted my- 
self) until year before last, when somehow they made several times more seed 
bulbs than I ever saw before. This last year they again made only a very few 
