30 CULTURE OF THE GRAPE. 



any instances of native and foreign hybridization. Cer- 

 tainly there is no inherent impossibility in thus crossing the 

 two species, they being closely allied in their nature and 

 characteristics ; so closely, indeed, that it is as difficult 

 even for experts to determine to which class some varie- 

 ties belong as it is in the case of the different native spe- 

 cies which have been mentioned. For example, it is still 

 in dispute whether the Rebecca and the Delaware are 

 pure ^foreign or pure native varieties, or whether they 

 have a mixture of the blood of each. If, then, there is 

 such similarity in the two classes, it certainly seems en- 

 tirely reasonable to suppose they may be intermingled. It 

 would seem very easy to determine this problem by actual 

 test ; but the experiment is more delicate than might at 

 first be supposed. In order that this subject of hybridi- 

 zation may be more distinctly understood, the following 

 description of the inflorescence of the grape is quoted 

 from Gray's " Manual of Botany : " 



" Calyx very short, usually with a nearly entire border, 

 or none at all, filled with a fleshy disk which bears the 

 petals and stamens ; flowers in a compound thyrsus ; pedi- 

 cels mostly umbellate-clustered; petals five, cohering at the 

 top; and so the corolla usually falls off without expanding." 



This compound thyrsus, or cluster of flowers, greatly 



