HORTICULTURAL EXPERIMENTS AT SAN ANTONIO. 21 



tiana (S. P. I. 28129) and Z. oxyphylla (S. P. I. 28130), are not hardy. 

 Both Ziziphus sativa 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 in 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 killing 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 be 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. 



Persimmon. — One of the most interesting new stocks now under 

 test is the native Texas persimmon {Biospyros 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 



