199 
providing an informal and beautiful edging to the perennials. 
In the Brooklyn Botanic Garden rock garden, in which glacial 
J 5 ) d 
boulders are used, the general idea in construction was to simulate 
such a rock-strewn slope as one would be likely to find on a 
terminal moraine, since the Botanic Garden is located on the 
slope of such a moraine. 
What is and what is not admissible to the rock garden in the 
way of plants is always a vexed question. We think of a rock 
garden primarily as a home for alpine and saxatile plants, and, 
in temperate climes, the bulk of its inhabitants should be drawn 
from this source. But not all of the mountain plants are desirable— 
some are nothing but lusty weeds, especially under lowland condi- 
tions—and there are many plants that fit admirably into the rock 
garden picture that would be excluded if measured by the yard- 
