(46) 



northern Asia, and 'its American representative, the prostrate 

 juniper, of northern North America, are both neat low-grow- 

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

 columnar habit, known as variety pyramidalis, are each pres- 

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

 of the Chinese juniper represented her. 



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 vegetation 

 which was common and widely distributed in tertiary geolog- 

 ical 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 



