The Garden Magazine, October, 1919 



91 



AN ALOOF GIANT IN MERCED GROVE, CALIFORNIA 



Here in a restricted area this once world-wide species has been 

 constrained to make its abiding place. (Sequoia gigantea) 



such we may instance the Araucarias, now confined to South 

 America and to Australia, New Zealand, and the adjacent 

 islands. A familiar example of this group is the Norfolk 

 Island Pine (Araucaria excelsa) so much in request for 

 indoor decorative purposes in the colder parts of this 

 country, and hardy in parts of California and the southern 

 States. Other examples are the Cycads found scattered in 

 many parts of the Southern Hemisphere and northward 

 to the Tropic of Cancer; the Cedars of Lebanon, of the Taurus 

 Mountains, Cyprus, the Atlas Mountains and the western 

 Himalayas; and the Ginkgo of China, Korea, and Japan. 



Many persons take it for granted that the types of trees 

 with which they are familiar are found all the world over; 

 others more discerning know that every tree has but a limited 

 distribution, covering at most a number of degrees of latitude 

 and longitude. They know that the Oaks, Elms, Maples, 

 Pines, and Firs are different on the eastern and western sea- 

 boards of this country; also that they both differ from those 

 of Europe on the one hand, and of eastern Asia on the other. 

 If one looks into the subject all sorts of curious facts are 

 unearthed. Some . groups of trees are represented by many 

 species, others are limited to one or two. For instance the 

 Tulip Tree, Kentucky Coffee Tree, and the Sassafras are 

 each represented by two species only, one of each here in the 

 eastern United States and another of each in central China. 

 As study follows interest it is clearly seen that some groups 

 are in the heyday of their youth, others in their prime, others 

 on the wane — not as individuals but as groups. 



REASONING on these facts the conclusion is reached 

 . that in the progressive development of types of trees 

 this is the natural sequence. It has been the same through- 

 out the world's history. Types have arisen and disappeared, 

 some completely; others have been altered and modified 

 to meet climatic and other changes and have persisted 

 through very long periods of time. The latter are, as it 

 were, living fossils. 



With two of these ancient types of trees I hope to deal at 

 length in succeeding articles. As an explanatory introduc- 

 tion, however, it is necessary to enter a little into the subject 

 of plant distribution in general — and although a popular 

 magazine is not the place for a full discussion of such matters, 

 they are of such importance and so suggestive that a few 

 salient points cannot fail to interest as well as help in an 

 understanding of the present phenomena of tree distribution. 

 Savants have written much to explain particular cases; and 

 as knowledge increases the whole question becomes more 

 simple. The geological records, however, even of the North- 

 ern Hemisphere, are notoriously imperfect. But as investi- 

 gations proceed many links are forged in the chains of evi- 

 dence and abysmal chasms are bridged; and though the 

 human mind, collectively or individually, will never achieve 

 the infinite, it may learn enough to explain intelligently 

 much that is still very obscure. 



If we are to understand in the least degree the present 

 distribution of plants, and especially the isolation of groups 

 of trees — like the Honey-locust for instance (Gledits) 

 and the Sweet Gum (Liquidambar) which occur in Asia 

 Minor, China and Japan, and North America, each separ- 

 ated by thousands of miles of land and sea — it is necessary 

 that we try to picture some of the changes time has wrought 



