1907.] PUBLIC DOCUMENT — No. 33. 211 



It will be seen that the pure-culture varieties gave much 

 larger yields than either the English or the French spawn. 

 While this difference is very great in this experiment, in- 

 dicating probably an inferior grade of English and French 

 spawn, all our experiments have shown a similar advantage 

 for the jDure-culture varieties. Indeed, it seems to be one of 

 the chief advantages of the new method of growing mush- 

 room spa^ai from pure culture that it nearly always gives 

 fresher and more vigorous spawn. The product is nearly 

 always more uniform, and of higher quality; but, while this 

 advantage is important, it is not so great as the one already 

 mentioned. 



A comparison of the different varieties shows that Eureka 

 (Agaricus arvensis) leads all the others in productivity, 

 Alaska coming second. This has been the result in all the 

 experiments in which these varieties have been tested. 

 Eureka is darker colored than any of the other varieties, 

 and sometimes not quite so well shaped; nevertheless, it is 

 solid and heavy, and of fairly good quality when cooked. 

 Galloway is a white, small, delicate variety, the best of all for 

 eating, but not sufficiently productive to pay the growler. 



The following conclusions may fairly be drawn from the 

 experiments : — 



1. Pure-culture spawn is as a rule very much better than 

 either English or French spawn. 



2. There are important points of difference between the 

 commercial pure-culture varieties; these differences consist 

 in color, flavor, form, and above all else in productivity. 



3. The most productive variety thus far tested is Eureka. 

 Several other varieties are promising. 



As a general result of our experience, it may be said that 

 mushrooms can often be grown profitably as a catch-crop in 

 cellars or under greenhouse benches where conditions are 

 favorable. The most important favorable condition to be con- 

 sidered is a cheap and reliable supply of fresh horse manure. 

 It is quite plain, however, from our experience, that the 

 stories of sudden wealth accumulating from mushroom-grow- 

 ing are mostly fictitious. 



