64 Addisonia 



the Spiraea crenata of Linnaeus, another and quite different plant 

 occurring from southeastern Europe to the Caucasus. This error 

 was detected later, and the name given to it commemorating its 

 discoverer, Thunberg. 



The genus Spiraea has over seventy-five species, mainly dis- 

 tributed in the temperate regions of the northern hemisphere, 

 extending in the New World as far south as Mexico, and in Asia to 

 the Himalayas. Many species are of great horticultural value, 

 and may be classed in two groups: those which, Uke the present 

 species, flower in the spring and early summer, and have white 

 flowers borne in umbels on the wood of the previous year; and 

 those which bear either white or pink blossoms, from early summer 

 to fall, in corymbs or panicles on vigorous shoots of the season. 

 It is evident, therefore, that pruning in the species of the first group 

 should be confined to thinning, or to removing the weak wood, as 

 otherwise the number of blossoms would be greatly reduced ; while 

 in the second group pruning may be done more vigorously, the 

 flowers coming on the shoots of the year. 



George V. Nash. 



Explanation OF Pi^xe. Fig. 1. — Flowering branch. Fig. 2. — Flower, X 4. 

 Fig. 3. — Leaves. 



