8 THIC I'LU.MS OF XliW YORK. 



The blossoms of plums arc very characteristic, giving in flowering 

 time a distinctive aspect to all species and distinguishing some horticul- 

 tural varieties. The flowers of all the species are borne in clusters, differing 

 in number of individuals, according to the species; so, too, the flowers in 

 the different species vary in size, color, in length of their j^eduncles, and in 

 pubescence, especially of the calyx. Flower-characters are constant, taking 

 them as a whole, yet there are some variations that must be noted. One 

 of the most marked of these is in the time of appearance of the flowers; 

 in the South they appear before the leaves but in the North with the leaves. 

 On the grounds of this Station there are notable exceptions to the latter 

 statement, with varieties of species showing considerable variation in this 

 regard. There are some remarkable variations within species as regards 

 size and color of the corolla and glands and pubescence of the calyx, depend- 

 ing upon the environment of the plant ; but on the whole these characters 

 are very constant. The fragrance of the flowers of plums varies from a 

 delicate, agreeable odor to one that is quite disagreeable in some species as in 

 Americana; the odor seems to be a constant character. 



Of all structures of the plum the fruit is most variable, yet fruits are 

 sufficiently distinct and constant, especially within species, to make their 

 characters ver}- valuable in classification. Species, whether wild or cul- 

 tivated, may be distinguished in greater or less degree by the period of 

 ripening of the fruits, though in this regard the cultivated varieties of 

 the several species vary greatly and in the wild state trees of native plums 

 in the same locality, even in the same clump, may vary in ripening as 

 much as from two to four weeks. Species are distinguished by size, shape, 

 color, flesh, flavor and pit among the grosser characters of the structure 

 and by amoimt of bloom, stem, cavity, apex, suture and skin among the 

 minor characters. The fruit is usually the first part of the plant to respond 

 to changed conditions. 



Characters derived from seed structures are generally accounted of 

 much value by botanists in determining species. Such is the case w4th 

 plums. This Station has a collection of stones of over three htmdred 

 cultivated varieties of plums and some specimens of nearly all the different 

 species. The stones illustrated in the color-plates in this book show that 

 this structure is quite variable in size, shape, in the ends, surfaces, grooves 

 and ridges, even within a species; nevertheless in describing the several 

 hundred forms of plums for The Plums of New York the stone has been 

 quite as satisfactory, if not the most satisfactory, of any of the organs of 

 this plant for distinguishing the various species and varieties. 



