78 ESTABLISHMENT OF A NATIONAL BOTANIC GARDEN. 



The grouping of plants in botanic gardens is susceptible of -widely different 

 treatments, depending upon the character and area of the land available, the 

 expense involved, and the facts and theories selected for illustration ; also in the 

 temperate zones, at least, upon the amount of greenhouse space available; also 

 on the relative importance given to landscape considerations and upon the areas 

 retained as natural forest, thicket, or meadow. The facts and theories capable 

 of demonstration may be grouped in a general way, first, as biological rela- 

 tionships ; second, as morphological and physiological features ; third, economic 

 applications ; fourth, geographical distribution ; fifth, esthetic and landscape 

 features. Practical considerations also enter largely in the groupings of any 

 kind. 



1. BIOLOGICAL RELATIONSHIPS. 



In this instance it is sought to illustrate species of various plant families in 

 juxtaposition, the groupings thus formed being located in relation to each other 

 in some predetermined sequence. There' are practical considerations, such as 

 certain orders of plants having both members which require sunshine and shade 

 that renders a rigid sequence of this grouping not always possible. 



Collections of trees (arboretum), of shrubs (fruiticetum), of vines (vitice- 

 tum), and of herbaceous plants, for the most part, at least, in separate areas. 

 Plants depending on different climates for growth are usually put in glass houses. 

 There is unually required in addition to this a museum of prepared plants, of 

 fruits, seeds, etc., of photographs and drawings to complete the biological 

 sequence. By indicating on the labels the native regions of plants biologically 

 grouped information on geographic distribution may be given. 



2. MORPHOLOGICAL AND PHYSIOLOGICAL FEATURES. 



The demonstration and illustration of structure and functions presupposes 

 some acquaintance with elementary botany. The rapid development of nature 

 study in schools will render grouping of plants, arranged, from these stand- 

 points, much more understandable. This grouping is much more likely to be for 

 the use of students than for the public. 



3. ECONOMIC APPLICATIONS. 



Plants grouped and labeled with reference to their uses, or the uses of their 

 products, are of direct interest to the public, coming closer to ordinary lines of 

 thought than any other features of the vegetable world, except those of beauty. 

 The arboretum illustrates the subject of forest products. Economic features of 

 shrubs and herbaceous plants are usually brought out by special classification 

 as food plants, drug plants, fiber plants, etc. These subjects can be very thor- 

 oughly illustrated by the formation of museums of economic plant products, 

 which is usually done in highly developed botanic gardens. 



4. GEOGRAPHICAL DISTRIBUTION. 



Groups of plants illustrating the botanical features of regions other than 

 those of the local botanic gardens may be installed, and this feature is usually 

 given more or less prominence in the collections of many gardens. This feature 

 is of immediate interest to the public. It has its limits on account of soil and 

 climate and is usually not complete. There are difficulties of growing trees and 

 shrubs and herbaceous plants in a small area where it is sought to group them 

 together on account of the trees casting too much shade for the lower plants. 

 With greenhouses large enough some of these groups may be installed quite 

 satisfactorily. Where funds are available it will be found advisable to install 

 both the biological and geological systems. 



5. ESTHETIC AND LANDSCAPE FEATURES. 



" The general public is more interested in landscape effects and in plants from 

 a standpoint of beauty than any other features of botanic gardens. Well-built 

 and well-kept grounds appeal to the people as attractive places to visit. They 

 are i bus brought in contact with the means intended to instruct them in some 

 of the branches of exhibition in a well-kept botanic garden. The residents of 

 cities are particularly attracted to woodlands, thickets, and meadows, particu- 



