CULTIVATION OF THE TRUE YAMS. 5 
seed bulbs. I received the yam under the name of White Jamaica, but do not 
know whether this name is correct. Mr. Burnett, who was quite a horticul- 
turist, said the botanical name was Dioxcorea alata. I grew the yams for live 
years near Palatka (at Florahome) and they did well on high hammock land. 
Down here in Dade County on very light sandy and rocky land they produce 
as much as sweet potatoes and with me take the place of Irish potatoes; the 
latter will not succeed on this dry soil at all. The yams keep for months. 
Tubers of the yam referred to in the foregoing letter were sent 
to the Department of Agriculture early in 1913 from Santa Rosa, 
Fla., by a cooperator who had previously obtained the variety from 
Mr. DeHoff. These were recorded under seed and plant introduction 
(S. P. I.) No. 37943. The species is Dioscorea alata, as stated in Mr. 
DeHoff 's letter. The same variety (S. P. I. No. 49496) was later 
obtained by the department from O. P. Wernicke, of Brooksville, 
Fla., who brought it from Avon Park, Fla., and still more recently 
(S. P. I. No. 52927) from Mr. DeHoff himself. 
Introductions of other varieties of yams from the Orient and the 
West Indies have been made by the Office of Foreign Seed and Plant 
Introduction at various times during the last 25 years and dis- 
tributed to interested plant experimenters. However, on account of 
the lack of definite knowledge by farmers concerning the crop and its 
requirements and the absence of the stimulus of a market demand 
these introductions have been largely without results. 
So far as known the first shipment of Florida-grown yams to a 
northern market was of the variety described by Mr. DeHoff, grown 
by O. P. Wernicke in 1918. Since 1918 there has been an insistent 
demand for the vegetable in the New York market, but the more rapid 
development of the industry has been prevented by the limited quan- 
tities of propagating material available and the unfamiliarity of 
farmers with the yam as a commercial crop. At the present time 
small commercial quantities of yams are being raised by a few farm- 
ers in the South, and about 400 persons are growing them experi- 
mentally and for home use. 
GROWING THE GREATER YAM. 
WHEN TO PLANT. 
Yams are often slow to begin growth in the spring, but it is found 
best when practicable to plant in southern Florida soon after the 
first of March. Planting as late as April 1 is sometimes satisfactory, 
however, and in northern Florida it may even be delayed until the 
last of April when necessary. The greater yam has been called the 
ten-months yam, but some varieties of it have produced fairly good 
tubers in eight to nine months. 
SEED TUBERS. 
Some varieties of the greater yam have a strong tendency at times 
to produce aerial tubers in the axils of the leaves, especially when 
the vines run on the ground. The development of this tendency 
in Florida often varies from year to year, perhaps because of differ- 
ences in weather conditions. These timers as well as those borne 
underground are used for propagation; but plants from very small 
aerial tubers produce rather small underground tubers the first year. 
