(62) 



only by the typical form, but by many horticultural va- 

 rieties, 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 medicine. The Chinese arbor vitae, 

 from China and Japan, has a number of specimens repre- 

 senting it and some of its horticultural 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 vegeta- 

 tion 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 Garden 



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 

 fringing the hemlock grove. This valley is about 1500 

 feet long and averages about 300 feet 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 three series: {a) The systematic plantation; 

 (b) the morphological garden; (c) the economic garden; 

 the viticetum, or collection of vines, is planted at an 

 arbor just east of the northern part of the valley. 



(a) Systematic Plantation 



This is located in that portion of the valley south of the 

 driveway crossing it, and here the plants are grouped by 

 natural families in botanical relationship. At the southern 

 end are the seedless plants, represented by the ferns and their 

 allies; east of the brook are the families of seed-bearing 

 plants belonging to the large endogenous division, or those 

 with parallel-veined leaves and with one seed-leaf (monocot- 



