420 



The Journal of Heredity 



This told aj^ainst such trees as the 

 famous Hooker Oak of Chico, Cal., 

 photographs of which were submitted by 

 half a dozen persons who will probably 

 be quite surprised to learn that it is 

 not the largest oak in North America. 

 Its smallest circumference (3 feet above 

 ground) is only 21 feet 8 inches. This 

 is almost insignificant in comparison 

 with the tree of the same species, 

 illustrated in Fig. 8. The Hooker Oak, 

 however, has a height of 105 feet and 

 it is probably on this account that the 

 famous English botanist. Sir Joseph 

 Hooker, who measured it in 1872, 

 pronounced it the largest oak in the 

 world, as far as his encyclopedic knowl- 

 edge extended. Dr. Charles Sprague 

 Sargent of the Arnold Arboretum, 

 Boston, who is ])erhaps the greatest 

 authority on North American trees, is 

 quoted as having said that he knows 

 of no other tree in the United States 

 which equals it in spread of branches. 

 The outer circitmference of the head 

 is about 450 feet, and it has been cal- 

 culated that, allowing 2 square feet of 

 shade to each ])erson, 7,885 people 

 might find shelter from the sun under 

 its branches. 



Among smaller species of trees, one 

 of the fine specimens sent in is the white 

 birch (Betula populifolia) on Switzer Hill 

 in the township of Athol, Worcester 

 County, Mass., the smallest circumfer- 

 ence of which is 12 feet 2 inches. This 

 is considerably larger than the maximum 

 ordinarily calculated for the white 

 birch. The photograph was sent in 

 by Philip R. Thayer, of Athol. 



VIGOROUS HYBRIDS 



As hybrid trees are notably va\nd and 

 vigorous growers, it is not sur])rising 

 to find some of them in any list of big 

 trees. Readers of the Journal of 

 Heredity will remember the great 



James Ri\'cr Walnut described by 

 Peter Bissct last year (Vol. V, p. 98). 

 That supposed cross between the butter- 

 nut {Julians cinerea) and the Persian, 

 impro]:)crly called English, walnut (/. 

 regia) is 31 feet 3 inches in circumference 

 at 4 feet from the ground, and is prob- 

 ably not much less than 200 years old. 

 Some of the hybrid walnuts jDroduced 

 for commercial purposes in California 

 during recent years have been reputed 

 to be the fastest growing hard wood 

 trees in the world, and notable among 

 them is the Paradox Walnut, a cross 

 between /. regia, the Persian (English) 

 walnut, and a black walnut. One 

 planted only about forty years ago at 

 Yuba City, Cal., has now attained a 

 circumference of 18 feet 7 inches at 

 4 feet from the ground, and a height of 

 100 feet. Photographs of it were sub- 

 mitted by H. H. Jacobs, of Santa 

 Barbara, Cal. It is likely that this 

 tree, which appears to be a natural, not 

 an artificial, hybrid, is a cross between 

 the Persian walnut and the black 

 walnut of northern California, Juglans 

 californica, var. hindsi. 



It is perhaps worth noting that the 

 name "Paradox" is the invention of 

 the California plant breeder Luther 

 Burbank, who applied it particularly 

 to his own crosses. By common usage, 

 however, it has now come to designate 

 any cross between the Persian walnut 

 and a black walnut, whether the latter 

 be the California species (J. californica) 

 or the common black walnut of the 

 eastern forests, /. nigra. Such crosses 

 are made very freely under natural 

 conditions, and in nurseries sometimes 

 take place to such an extent as to be 

 really troublesome to the horticulturist. 

 The California black walnuts also cross 

 readily with the eastern black walnut, 

 the resultant hybrid being designated, 

 after Burbank, as "Royal." 



A TRKK FAVOKKI) in LIMHEKMEN (,S,«- opposiu pajic) 



The yellow jKjplar or tulij) tree {Liriodcndron tulipijera) is a favorite with lumbermen in the 

 Southern State.s, because of tlie lar^e amount of timber which can lie cut from its trunk. 

 As shown above, its growtli habit is such as to allow the ])ro(luction of the maximum 

 number of board feet. This sfjecimen, which is considerably larger than the limit for 

 the species set in the manuals of forest trees, grows on Reems Creek, N. C, and was 

 I)hotograi)hed by John R. Hess, of Providence, R. I. He gives the height as l')8 feel 

 and the circumference, 4 feet above the ground, as 3+ feet 6 inches. It is indis])utably 

 one of the finest tulip poplars in the United States. (Fig. 14.) 



