THE GRAPES OF NEW YORK. 105 



stamens around the pistil, the others bear smaller stamens, shorter than 

 the pistil which soon bend downward and curve under it; these may be 

 called imperfect hermaphrodites, approaching females, and they do not seem 

 to be as fruitful as the perfect hermaphrodites, vmless otherwise fertilized." 



Beach' tested many of our cultivated varieties by sacking the clusters 

 at blooming time and thus determined their capacity to fertilize them- 

 selves. From the data thus secured he divides them into four classes: 

 I St. Those that are able to fertilize themselves so that the clusters are per- 

 fect or varying from perfect to somewhat loose. 2d. Those in which the 

 clusters are marketable, varying from moderately compact to loose. 3d. 

 Clusters so loose as to be unmarketable. 4th. Those which are self-sterile 

 or showing no fruit on covered clusters. Of 169 varieties tested, he found 

 38 belonging to the first class, 66 to the second class, 28 to the third, and 

 37 to the fourth. 



Later it was found that the reason why certain varieties were self- 

 sterile was on account of impotent and abortive pollen, the percentage of 

 abortive pollen grains varying with different varieties and this percentage 

 determining the degree of self-sterility. The upright or depressed stamen 

 is not an invariable criterion of the condition of the pollen although it is 

 usualh'. There are a few instances in which upright stamens bear impotent 

 pollen but these are very exceptional. Munson made similar tests of vines 

 of twenty-two' American species of vines secured from their habitats. In 

 every case he found that they showed only two forms, the staminate vines 

 and the self-sterile hermaphrodite, no perfect hermaphrodites being found. 

 While of some of the species the number of vines tested was a half dozen 

 or less, in most instances many vines were tested from different places. 

 This is particularly interesting in that it becomes a puzzle as to where ovir 

 perfectly hermaphrodite cultivated forms covild have come from if such 

 forms are not present in the wild vines of our woods and prairies. 



The structure of the bark is an important distinguishing character for 

 some species; in particular as to whether it peels off and whether in large 

 flakes or in narrow strips or shreds. So, too, the color of the bark is often 

 of taxonomic importance. The form and color of the leaves are often 



' -V. Y. Sta. An. Rpt.. 17:518. 1898. .V. V. Sta. Bid. 157. iSg8. 

 ^ Tex. Sta. Bill., 56:239. 1900. 



