RARE TREES AND SHRUBS IN THE ARNOLD ARBORETUM, U.S.A. 23 



parts of the world ; the first laying out and planting in a 

 methodical manner of the botanical collection. 



Some years ago an agreement was made between the city of 

 Boston and Harvard University, giving the city the right of 

 including the grounds of the Arnold Arboretum in their system 

 of parks, on the condition of providing a police force and making 

 the roads and drives through the Arboretum. This work is 

 now very nearly finished. The boggy places have been trenched, 

 the soil has been in most places deeply worked, and is almost all 

 ready for actual planting. Except a few acres that will be kept 

 in their present state of a wild and natural woodland copse, 

 and the space required for propagating and nursery purposes, all 

 the grounds are to be planted according to the following general 

 principles: The botanical families will be planted as much" as 

 possible in their natural sequence, but advantage will be taken 

 of the differences of soil and aspect to place each genus or species 

 in as good a situation as possible so far as light and soil and 

 water are concerned, the most prominent places being reserved for 

 the American specimens of a genus. Of every large-growing 

 tree five to ten specimens are planted, one receiving more space 

 and a more suitable position to enable it to grow into a specimen 

 tree, and the others being more or less closely grouped. 



Nearly one -third of the ground is now planted in this way. 

 The making of the roads and the necessary working and 

 trenching of the land in many places prevented any quicker 

 advancement of the work. Indeed, the amount of work already 

 done is enormous. Many species of trees are already 20 feet 

 high, and the number of the different shrubs in some of the 

 beds or natural-looking thickets is to be counted by hundreds 

 of thousands in this park of 175 acres. 



Where the actual plantations have been made, the natural 

 outgrowth of the soil in wild plants and shrubs is permitted to 

 cover the ground, in order to shelter and protect the newly 

 planted trees and keep the soil cool and moist. Kalmia angusti- 

 folia, Myrica asplcnifolia, &c, quickly spring up and form 

 thick carpets, proving that the soil is nearly destitute of lime- 

 stone, which is a great advantage for the cultivation of an 

 extensive collection of woody plants, as a great many of them, 

 especially in the leguminous or conifer orders, would be injured 

 by the presence of any appreciable amount of chalk or limestono 

 in the soil. 



