The members of the squash tribe are readily fertilized, as illustrated in earlier pictures of this volume, but the hybrids tend to show extreme variation, and they are very difficult to fix. Mr.Burbank has shown, however, that it is not impossible to fix new varieties by careful selective breeding. The squash here shown was developed from seed sent from South America. It has almost the solidity and weight of a cannon ball.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 3 Chapter 7