— iSi — 



mon observations concerning these plants are incorrect. All the 

 species are exceedingly variable, and it is easy to select fruits 

 from large plantations which bear some external resemblance to 

 fruits of other species, and it is natural to suppose, in the pres- 

 ent confused state of our knowledge of hybridity, that such fruits 

 are hybrids. 



I began definite experiments in crossing cucurbits in 1S87, and 

 selections and close observations were begun before that time. 

 The work has been continued upon a large scale, and I have now 

 made fully 1,000 careful hand pollinations, and have obtained no 

 less than 1,000 types of pumpkins and squashes never recorded. 

 The plantations of selections and crosses covered some eight acres 

 this year. 



The experiment is only begun. The main results of it can not 

 be announced until further work has been clone. But some of 

 the incidental features of the research can be stated from time to 

 time. 



1 . Immediate effect of crossing. — The ' ' immediate effect of cross- 

 ing' ' is a term used to denote any change which may occur in the fruit 

 the same year the cross is made, as a result of the influence of pollen. 

 Whatever effect the pollen may have is usually shown in the off- 

 spring of the crossed fruit rather than immediately, the same 

 season, in the fruit itself. There are but few plants in which an 

 immediate effect of crossing has been proved, and of these Indian 

 corn is the most familiar. It is commonly said that it occurs in 

 pumpkins and squashes, also ; but it certainly does not. There 

 has never been any immediate influence whatever in any of our 

 crosses, except such as was due to imperfect development caused 

 by insufficient or impotent pollen. In other words, the effects of 

 the cross are seen only in the offspring of the fruits. 



It is easy to prove, without the aid of artificial pollination, even 

 among the most variable squashes, that there is no immediate 

 effect. If there were an immediate effect, all the fruits upon a 

 vine would be likely to be different, as every one would probably 

 receive a different pollination. This diverse pollination would 

 almost inevitably result if many varieties were planted close to- 

 gether, for the flowers of pumpkins and squashes are imperfect 

 and cannot pollinate themselves. But the fact is that all the 

 fruits on any vine are alike, with some trifling exceptions in rare 

 cases due to arrested development or the like : the essential char- 



