372 
ern States; to make the collection as valuable as possible for this 
purpose only well-known hardy shrubs are included in it. Less 
hardy and all imperfectly known shrubs will be found in more 
sheltered and less conspicuous positions, where supplementary col- 
lections of most of the prominent genera of shrubs are main- 
tained.” 
3. Crataegus collection. “ About 1300 species, forms, and va- 
rieties of this genus are now represented in this collection. The 
plants were nearly all produced at the Arboretum, from seeds 
carefully gathered from the individual trees which served as the 
types from which the species were described. The plants are in 
square beds, and several individuals of each species are planted 
together ; then as these grow they are reduced to one or two plants 
of each variety. Diagrams of each bed are kept on cards, and 
the name, history, position, and final distribution of each indi- 
vidual are recorded.” 
4. Pinetum, containing the pines and other Gymnosperms. 
5. Special features: In addition to the beautifully landscaped 
grounds and very large collections of hardy woody plants, several 
features are worthy of special note. These include Hemlock Hill, 
a beautiful natural group of the native hemlock (Tsuga canaden- 
Sis), a great lilac collection, containing in excess of 400 named 
species and varieties, vast collections of azaleas, attractive mass 
plantings of rhododendrons and laurel, extensive plantings of ori- 
ental cherries and crab apples, and the remarkable Larz Anderson 
collection of dwarfed Japanese trees, the latter presented in 1937. 
Publications: Shaw, G. R., The Pines of Mexico. Bosten. 1909. 
—Rehder, Alfred, The Bradley Bibliography; a guide to the 
literature of woody plants published before the beginning of the 
twentieth century. 5 vol. Cambridge. 1911-18—Sargent, C. 
S., Plantae Wilsonianae; an enumeration of the woody plants 
collected in western China. 3 vol. Cambridge. 1911-17.— 
Shaw, G. R., The Genus Pinus. Cambridge. 1914—Tucker, 
Ethelyn M., Catalogue of the Library of the Arnold Arboretum. 
3 vol. Cambridge. 1914-33.—Wilson, E. H., The Cherries 
of Japan. Cambridge. 1916—Wilson, E. H., The Conifers 
and Taxads of Japan. Cambridge. 1916.—Wilson, E H., and 
Rehder, Alfred, A Monograph of Azaleas. Cambridge, 1921— 
