GRAPE BOTANY 307 



Petiole : The leaf-stalk. 



Petiolar sinus: The sinus about the petiole. 



Basal sinuses: The two sinuses toward the base of the blade. 



Lateral sinuses: The two sinuses toward the apex of the blade. 



The size, shape and color of the leaves are quite distinctive 

 of species and more or less so of varieties, if allowances are 

 made for variation due to environment. The lobing of leaves 

 is a very uniform character in most species, some liaving lobes 

 and others having entire leaves. The upper surface of the leaf 

 in some species is smooth, glossy and shiny and in others is 

 rough and dull. The lower siu-face shows similar variations 

 and has, besides, varying amounts of pubescence, down and 

 bloom. In some species the down resembles cobwebs. The 

 number, size and shape of the lobes are important in distinguish- 

 ing both varieties and species, as are also the petiolar, basal and 

 lateral sinuses. As in most plants, the margins of the leaves, 

 whether serrate, dentate or crenate, are often distinguishing char- 

 acters. The petiole in different species varies from short to 

 long and from stout to slender. Lastly, the time at which the 

 leaves fall is often a good distinguishing mark. 



The fruit. 



Peduncle and pedicel: Defined as in flower. 



Brush : The end of the pedicel projecting into the fruit 



Base: The point of attachment of bunch or berry. 



Apex: The point opposite the base. 



Bloom: The powdery coating on the fruit. 



Pigment : The coloring matter in the skin. 



Quality: The combination of characters that makes grapes pleasant 

 to the palate, sight, smell and touch. 



Foxiness : The rancid taste and smell of some grapes which are 

 similar to the efflu\ium of a fox. 



Of all organs the fruit is most responsive to changed condi- 

 tions and hence most variable. Yet the fruits furnish most 

 valuable characters for determining both species and varieties. 

 Size, shape, compactness and the number of clusters on a shoot 



