ARBORETUM 



ARBORETUM 



351 



collections of several of the large genera of shrubs have 

 been established, usually in sheltered positions, in which 

 are planted new or imperfectly known species or species 

 that require unusual care or special protection. 



The collections of the Arnold Arboretum are rich in 

 the woody plants of eastern North America, northern 

 Europe, Siberia, China and Japan, and contain the 

 largest number of species and varieties of these plants 

 to be found in any American collection; and gradually 

 the Arboretum, with its hills and valleys, its native 

 woods and varied vegetation, has developed into one of 

 the most beautiful of all the public gardens of the 

 world. 



A large part of the trees and shrubs planted in the 

 Arboretum has been raised in its nurseries from seeds 

 collected in those parts of the region occupied by the 

 species in which the climate most resembles that of 

 New England. A record of the origin and history of 

 all the plants is kept on the cards of a catalogue, and 

 the position of every tree permanently planted in the 

 groups is recorded on the sheets of a large scale map, 

 and with this is kept the detailed history of each tree. 

 Labels giving the Latin and English names and the 

 region that they inhabit are placed at the height of 

 the eye on the trunks of prominent native trees standing 

 near drives and walks, and these labels are found on the 

 trunks of many of the planted trees in the different 

 groups. Metal labels with raised letters are used for 

 the plants in the shrub collection and for shrubs and 

 small trees near some of the walks. Wooden stakes 

 giving their names are placed before many shrubs and 

 small trees; and to every plant, whether otherwise 

 labeled or not, a small zinc label is attached. 



In order to make the Arnold Arboretum a scientific 

 station and something more than a collection of living 

 trees, an herbarium of woody plants intended event- 

 ually to represent the ligneous vegetation of the world 

 and a library now containing 29,000 bound volumes 

 and 6,000 pamphlets have been formed. An herbarium 

 and library connected w^ith such an institution are 

 essential for the determination and correct labeling 

 of the living collections and make possible original 

 scientific work. A report on the forest wealth of the 

 United States, the reports of state and national com- 

 missions appointed to study American forest conditions, 

 the illustrated "Silva of North America," the "Manual 

 of the Trees of North America," a "Forest Flora of 

 Japan," "Trees and Shrubs," a monograph of the genus 

 Lonicera, a monograph of the pines of Mexico, many 

 of the articles on trees and shrubs in this Cyclopedia, 

 the ten volumes of Garden and Forest, the Jesup collec- 

 tion of North American woods in the American Museum 

 of Natural History in New York, are some of the con- 

 tributions to knowledge which the arboretum as a 

 scientific station has been able to make. For several 

 years, it has been actively engaged in bibliographical 

 studies, and the results of these studies are being 

 published in the "Bradley Bibliography," of which two 

 volumes have appeared. An elaboration of the woody 

 plants of China is in progress, based largely on the col- 

 lections of E. H. Wilson, one of the arboretum explorers, 

 and is now being published by the arboretum in the 

 "Plants' Wilsonianse." 



In connection with its work in search of material for 

 its collections, officers and employees of the arboretum 

 have visited nearly every part of North America, have 

 traveled in Peru and Chile, and explored the Caucasus, 

 Japan, Korea, and northern and western China. 

 Through these explorations, the Arnold Arboretum 

 has been able to introduce into the gardens of the 

 United States and Europe a large number of new plants 

 or plants that have been long lost to cultivation, and 

 through these introductions it has established relations 

 in all countries with the principal botanic gardens, 

 the important nurserymen and many individuals inter- 

 <vtrd in trees and their cultivation. 



The work the Arnold Arboretum attempts and the 

 demands which are made on it are national in scope and 

 extent, but for a national American arboretum a more 

 temperate and equable climate than that of Massachu- 

 setts is desirable. Its situation, however, in the midst 

 of a population famous for its generosity and actively 

 interested in horticulture, and the stability it enjoys 

 from its connection with a great university, and from its 

 contact with the city of Boston, are favorable to it. 

 It is impossible, however, to cultivate in one collection 

 the trees which grow naturally or can be made to grow 

 in all the different regions of the United States, and 

 the American national arboretum of the future must 

 first of all be an institution, like the Arnold Arboretum, 

 of long life 

 and continu- 

 ous control; 

 and this cen- 

 tral institu- 

 tion properly 

 equipped 

 with labora- 

 tories and 

 material for 

 research must 

 be in a posi- 

 tion to estab- 

 lish branches 

 in Florida, 

 Arizpna,Cali- 

 fornia and in 

 some central 

 regions of the 

 continent, for 

 in such bran- 

 ches managed 

 by the central 

 institute, i t 

 would be pos- 

 sible to col- 

 lect and to 

 study nearly 

 all the trees 

 of the world 

 suitable for 



different parts of the country, and so make possible in 

 the United States an arboretum really national in 

 character. 



Herbaria are chiefly valuable when they supplement 

 collections of living plants; and it is now becoming grad- 

 ually acknowledged that accurate knowledge of trees 

 and of many other groups of plants can be obtained only 

 by a comparative study of the plants themselves. The 

 opportunity for this will be found only in establish- 

 ments in which plants in large groups can be assembled 

 and grown under conditions favorable for their best 

 development. Today the palms of the tropics, especi- 

 ally those of the Old World, can be satisfactorily stud- 

 ied only in the great collection of these plants gathered 

 together in the botanic garden at Buitenzorg in Java. 

 Some groups of northern trees and shrubs can now 

 best be observed in the Arnold Arboretum, but to 

 obtain exact information of others the student must 

 make long and sometimes difficult journeys. Until, 

 for example, collections of the cactacea; and of plants 

 like the agaves and yuccas are assembled in a region 

 favorable to their growth, like southern New Mexico or 

 Arizona, it will be impossible to obtain a true under- 

 standing of these plants which, when grown in northern 

 greenhouses or in regions unsuited to their peculiar 

 needs, more often mislead than illuminate. Com- 

 prehensive collections of the species of eucalyptus, 

 acacia and other Australasian plants established in 

 California would be of great value to that state; 

 and collections of tropical and subtropical plants in 

 southern Florida would immensely benefit not only 



311. Trees still standing in the Humphrey 

 Marshall collection. 



