XXXVlll 



INTRODUCTION. 



ROSACEA. 



ROSE TRIBE. 



This extensive order, ^yhicll comprises nearly 

 all the fruit-trees of the temperate regions which 

 are valuable to man, has been subdi^-ided by 

 modern botanists into Drupaceae, Pomaceae, San- 

 guisorbaceas, and Rosaceas. The plants of all 

 these sub-orders or groups are marked by bearing 

 an indefinite number of stamens on the calyx and 

 agree in some other particulars. 



Drupace.e. 



cherry group. 



The plants of this group are distinguished by 

 bearing what is technically called a drupe, that is, 

 a fleshy or pulpy fruit enclosing a hard stone, and 

 by the presence of prussic acid in their leaves and 

 kernel. They are natives exclusively of the cold 

 and temperate climates of the northern hemi- 

 sphere, but in a cultivated state are diffused 

 throughout most parts of the world. The poison- 

 ous properties of prussic acid are too well known 

 to require any notice : yet, notwithstanding the 

 presence of this destructive principle in the leaves 

 and other parts of the trees belonging to this 

 group, the fruit is with very few exceptions 

 harmless, or even a nourishing food. The sub- 

 order includes the Almond, Peach, Nectarine, 



