CXXXI.— THE DWARF CHERRY. 
Prunus Cerasus Linne. 
I F Rosa is an isolated genus, Prunus, in the wide sense, is even more so. With the 
exception of a remarkable North American genus Nuttallia, which has five free 
carpels of a leathery texture and thus appears to form a link with the Sub-Family 
Spirceoidet2, it constitutes the entire Sub-Family Prunoidece in Dr. Focke’s classification 
of the Rosacea ; and this group has long been generally known, on account of the 
fruit of Prunus, as the Drupacece. This type of fruit, consisting of a single carpel, 
superior, i.e. entirely free of all adhesion to the receptacular tube, containing two 
pendulous ovules, only one of which usually becomes a seed or “ kernel,” and 
forming three distinct layers in its pericarp, the “ skin,” “ flesh,” and “ stone,” 
or epicarp, mesocarp, and endocarp, does not occur precisely with these characters in 
any other genus. All the members of the Sub-Family are woody plants and all 
have simple leaves with stipules not united to the petiole. The flowers are 
pentamerously symmetrical and produce honey : the calyx is deciduous and the 
stamens are not more than twenty in number. A physiological affinity running 
through the whole of the genus is shown by the formation to a greater or less 
extent of almond oil and prussic acid in leaves and kernels, and by the occurrence of 
what are termed “ extra-floral nectaries ” on the leaf-stalks. These structures, which 
commonly appear as two or more blackish spots near the base of the leaf-stalk, 
exude nectar, and in other cases in which they occur are supposed to be useful in 
attracting ants, which protect the tree from the ravages of other insects — an 
explanation that seems hardly sufficient in the case of these trees of Temperate 
latitudes. 
The genus Prunus in its widest sense is readily subdivided by the methods in 
which the leaves fold in the bud, the character of the surface of the epicarp and 
that of the “ stone ” or endocarp. Almonds, Peaches, Nectarines, Cherries, and 
Cherry -laurels agree in having their leaves folded lengthwise down the midrib like 
the two halves of a sheet of note-paper, or, as it is technically termed, conduplicate ; 
whilst those of Plums and Apricots are convolute, or rolled up like a scroll. Almonds, 
Peaches, and Apricots have a downy epicarp ; Nectarines, a smooth but not much 
polished one ; Plums, a covering of glaucous waxy “ bloom ” ; and Cherries and 
Cherry-laurels, a high polish, without either down or bloom. Lastly, the Almonds, 
Peaches, and Nectarines are widely separated from the rest by having the endocarp 
or stone of the fruit deeply corrugated with furrows or pitted with large holes, so 
that these are commonly detached as Linn^’s genus Amygdalus. 
The Cherries and Cherry-laurels have also often been erected into a distinct 
genus, Cerasus, characterised by the conduplicate leaves, polished fruit, and smooth 
endocarp, and it may be subdivided into the Laurocerasi, or Cherry-laurels, with 
evergreen leaves and flowers in racemes ; the Padi, or Bird Cherries, also with their 
