THE PLUMS OF NEW YORK. 3 



the almond the stone resembles in general characters the peach -stone, but 

 all almond shells are more or less porous and often fibrous on the inner 

 surfaces. The stone is the part for which the almond is cultivated and is 

 most variable, the chief differences being that some have thick hard shells 

 and others thin soft shells. 



The leaves of plums are convolute, or rolled up, in the bud. Cherry, 

 peach and almond leaves are conduplicate, that is are folded lengthwise along 

 the midrib in bud while the leaves of the apricot, like those of the plum, 

 are convolute. The manner in which the leaves are packed in the bud 

 is a fine mark of distinction in stone-fruits. In size and shape of leaves, 

 as well as in the finer marks of these organs, the botanist and pomologist 

 find much to aid in distinguishing species and varieties but little that holds 

 in separating the sub -genera. The last statement holds true with the 

 floral organs also. 



The near affinity of the stone-fruits is further shown by the fact that 

 plums and apricots, plums and cherries, and the several species of each 

 of the distinct fruits inter-hybridize without much difficulty. It is a fact 

 well-known that hybrids often surpass their parents in vigor of plant and 

 in productiveness and' this has proved true with most of the hybrids in 

 Prunus of which we have accounts, thereby giving promise of improved 

 forms of these plants through hybridizing. The great variation in wild 

 and cultivated native plums is possibly' due to more or less remote hybridity. 



Prunus is a most variable genus. This is indicated by the several 

 sub-genera, the large number of species and the various arrangements of 

 these groups by different authors. At their extremes sub-genera and species 

 are very distinct, but outside of the normal types, and sometimes in sev- 

 eral directions, there are often outstanding forms which establish well- 

 graded connections with neighboring groups. For example, among the 

 American plums there are but few species between which and some 

 other there are not intermediate forms that make the two species 

 difficult to distinguish imder some conditions. There is also a wide range 

 of variation within the species. The modifications within the species 

 are oftentimes such as to change greatly the aspect of the plant ; the trees 

 may be dwarf or luxuriant, smooth or pubescent; may differ in branching 

 habit, in leaf -form, in size and color of the flowers, in the time of opening 

 of leaf and flower-buds, in color, shape, size, flesh, flavor and time of ripen- 

 ing of fruit, in the stone and in all such characters as climate and soil envir- 

 onment would be liable to modify. 



