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ing sorts. The Chinese juniper, and its striking form, of col- 

 umnar habit, known as variety fy ramtdalis, are each present 

 in a number of specimens. There are still other varieties of 

 the Chinese juniper represented here. 



At the westerly end of this same area is the arbor vitae 

 {Thuja). The species of this genus produce a durable wood, 

 which is of especial value where there is contact with the 

 soil. The Japanese arbor-vitae is represented by a single 

 specimen. The common arbor-vitae, or white cedar, from 

 northeastern North America, is fully represented, not only 

 by the typical form, but by many horticultural varieties, some 

 of them very decorative. The wood of this tree is valued 

 for fence posts, railway ties, etc., and from its young branches 

 fluid extracts and tinctures are made which are used in medi- 

 cine. The Chinese arbor vitae, from China and Japan, has 

 a number of specimens representing it and some of its horti- 

 cultural forms. 



The maiden-hair tree family is represented by a single 

 species, the maiden-hair tree, several specimens of which 

 may be found on the southern portion of the westerly ridge 

 of the herbaceous grounds. This interesting tree, with its 

 fan-shaped leaves, is a remarkable relic of a type of vege- 

 tation which was common and widely distributed in tertiary 

 geological time, but is now restricted to eastern temperate 

 Asia in this one species, Ginkgo biloba. 



4. The Herbaceous Grounds 



The collection of hardy herbaceous plants is situated in a 

 valley southeast of the public conservatories, and between 

 the main driveway and the western border of the woods fring- 

 ing the hemlock grove. This valley is about 500 meters 

 long and averages about 100 meters wide. A small stream 

 runs through the valley from north to south and is here and 

 there broadened out into pools. The collections are arranged 

 in two series : (a) The systematic plantation ; (b) the morpho- 

 logical garden ; a third series (c) to illustrate economic plants, 



