170 THE MONTHLY BULLETIN. 



truDk was inoculated with pear blight in twenty-five places on three 

 diflt'erent dates. This same tree has been inoculated at forty points 

 on the tap-root and main branch roots on four different occasions. 

 These inoculations have never developed the slightest trace of the 

 disease. Check trees of Bartlett, Forelle, Pynm pashia, and French 

 pear seedling, inoculated on the same dates, with the same lots of 

 bacteria, developed the disease readily, and part of them are already 

 dead. 



A two-year old tree of another type of Pyrus calleryana has been 

 repeatedly inoculated in the tips of tender, vigorous shoots and on the 

 trunk, but it has never shown a trace of the disease on the trunk. 

 The inoculations on the young tender shoots developed the disease 

 readily, which extended down these shoots until it reached the hard 

 one-year old wood, where it stopped. 



Whether the seedlings from the trees at Oroville will show this same 

 degree of resistance remains to be determined. If the blossoms are 

 not cross-fertilized with pollen from some other species, these seedlings 

 will undoubtedl.y show as great resistance as the parent trees. We 

 have a large number of seedlings of this species growing at this station, 

 and as soon as the trees are large enough inoculation experiments will 

 be started. 



HABITAT. 



Pyrus calleryana is a widely distributed species in China, and is 

 found in the southern, eastern, central, and western parts. It grows 

 at elevations of from a few feet above sea level to a height of 5,000 feet, 

 being especially abundant at elevations of from 3,000 to 5,000 feet. 



The Oroville type of this species is especially abundant in south- 

 eastern and eastern China. Mr. Compere found it abundant along the 

 rivers and in the swamps between Hongkong and Canton, sometimes 

 growing vigorously under the most adverse conditions. Since the type 

 at Oroville came from near Hongkong, which has a tropical climate, it 

 is possible that it will not prove hardy in cold climates. This, however, 

 is not necessarily true, but it should be tested in cold regions before it 

 is extensively planted. The trees are perfectly hardy at Oroville, Cali- 

 fornia, and appear to be hardy in southwestern Oregon. Pyrus cal- 

 leryana, collected in central China, is hardy at Boston, Massachusetts. 



VALUE AS A STOCK FOR OUR CULTIVATED VARIETIES. 



This species, so far as I can ascertain, has not been thoroughly 

 tested as a stock for our cultivated varieties of pears. There is nothing 

 to indicate that it will prove unsatisfactory. 



This station has a two-year old tree of Pyrus caUcrj/aua, which was 

 grafted on the common French seedling, Pyrus co))n}iunis, and this is 

 growing especially well on this stock. We also have the Oroville type 

 and other types of this species growing on some of the common varieties 

 of Pyrus communis and also on the Chinese sand pear. In all cases 

 they appear to make a satisfactory union. As soon as our set^llings of 

 Pyrus calleryana have reached the proper size, a large number of them 

 will be budded with Bartlett and other varieties. 



