1904] SMITH—PUCCINIA ASPARAGI 25 
repeatedly verified from year to year. In New York and New Jersey 
large asparagus districts exist of practically uniform soil and of the 
nature characterized by the Massachusetts investigators as most 
favorable to rust. In these districts the disease became exceedingly 
virulent at first and completely exterminated the original beds, with- 
out regard to slight differences in soil or other features which are 
well marked in the new plantations of the same districts, now that the 
severity of the attack has somewhat subsided. Since dew is neces- 
sary for infection, it is but natural that where other conditions were 
equal, the progress of the disease should be temporarily marked by 
varying amounts of atmospheric moisture, but it must be said that 
throughout the eastern states dew is so generally abundant, even in 
the driest seasons, that nothing of permanent value can be credited 
to this relation. That dew is absolutely necessary to the develop- 
ment of the fungus seems proved from the effects of tree shade in 
asparagus fields, and this is the direct water-relation of this parasite. 
Conditions in California with respect to soil and atmospheric 
moisture are totally different from those of any eastern state. On 
account of the long, rainless summers, marked differences in the 
natural conditions of various parts of the state, and the prevalence of 
irrigation, any question having to do with moisture problems can be 
followed with a degree of precision quite impossible under the natural 
conditions of the east. This refers particularly to the degree of 
dryness obtainable, both of soil and atmosphere, a degree approxi- 
mated nowhere else in the country save in the adjoining semi-arid 
states. The principal asparagus-growing section of California has 
proved to be especially well-adapted to a study such as that herein 
described, and a description of this portion of the state must be given 
at this point. 
If in the accompanying map (jig. 3) a triangle be imagined between 
the cities of Sacramento, Stockton, and Antioch, it will include, at 
a safe estimate, sooo acres of asparagus. This country is at the 
confluence of the two great rivers of California, the Sacramento and 
the San Joaquin, together with a smaller stream, the Mokelumne, 
which enters the angle formed by the other two where they join. 
These rivers do not run directly into one another, but form, in the 
triangle just mentioned, a delta, composed of an intricate network of 
