HORTICULTURAL EXPERIMENTS AT SAN ANTONIO. 21 
tiana (S. P. I. 28129) and Z. oxyphylla (S. P. I. 28130), are not hardy. 
Both Ziziphus satwa and Z. jujuba are perfectly hardy and have 
made an excellent growth. Many of the better varieties so highly 
esteemed in China are being assembled at this station. As yet this 
fruit is more of a novelty than a product of commercial value, but 
when properly prepared it is considered a delicacy in this country as 
well as im China. 
Quince.—Only one variety of quince has been tested, and it has not 
made a satisfactory showing. It is very probable that this fruit is 
out of its zone here. 
Olive-—The Chemlaly and Aberkan olives have been grown here for 
several years, but the climate appears to be too severe for them. 
Date.—Although it is probable that the San Antonio climate is 
entirely too humid for the date to ripen fruit, the seedlings grown are 
quite hardy, and the tree is valuable as an ornamental. Tempera- 
tures of 12° F. have been experienced without killmg the plants, 
although the leaves are generally injured by temperatures below 20° F. 
TESTING RESISTANT STOCKS. 
One of the most promising and important lines of horticultural 
investigation at the present time is the determining of stocks resistant 
to the local soil troubles. Not only is there a great difference in the 
power of resistance in different species, but there is also a very notice- 
able difference in the resistance of different varieties of the same spe- 
cies. As an illustration, many of the seedlings of the Spanish race 
in the Mexican peach orchard are quite immune to chlorosis, while 
almost invariably those of the South China group are very susceptible. 
Certain varieties of persimmon are resistant, while others are severely 
affected. 
The richness of the native flora in economic plants, some of which 
may he utilized as stocks and others for hybridizing experiments, 
together with those which have been assembled from this country 
and by the importation of those which have indicated their suscepti- 
bility or resistance to soil disorders, forcibly emphasizes the import- 
ance of this line of effort. This work has received special attention 
the past three years. ‘The preliminary results indicate very dis- 
tinctly not only that many of the better varieties of fruit which are 
not considered adapted to these conditions may be utilized, but that 
additional fruits not commonly grown here may be added to the list. 
Persummon.—One of the most interesting new stocks now under 
test 1s the native Texas persimmon (Diospyros texana). This is being 
used as a root for both the American and the Japanese persimmon. 
It has been found very difficult to work other persimmons on this 
stock, and many previous attempts have resulted in failure where 
ordinary methods were used. During the spring of 1912 a number of 
