273 



THE GROWING TREE. 



(Continued from p. 259.. Tart XLVI1I.) 



E. — Nanism. 



Nanism or dwarfing may arise from more than one cause, or from a combination 

 of them. As a rule, the most obvious factor is prevalence of strong winds, and where 

 this is accompanied by shallowness of soil, we have a couple of important factors. It 

 is notorious that trees become dwarf in exposed situations near the sea, and on high 

 mountains; indeed, we can trace the diminishing size of a species according to the 

 varying shelter individuals receive. 



Examples of the effects of the strong sea air in diminishing size, taken almost 

 at random, are, at First Point, near Kincumber, Broken Bay, New South Wales, where 

 Mr. R. H. Cambage and I saw E. resinifera 8m. flowering at 4-5 feet, E. umbra R.T. 

 Baker at 4-5 feet, E. panicidata Sm. at 6 feet. Normally these species are medium-sized 

 to large trees. 



"e>^ 



F.— The Flowering of Eucalypts while in the Juvenile-leaf Stage. 



" The generative maturity of plants is not connected immutably with a definitive 

 stage of development."' There seem so many cases in which flowering and fruiting 

 have been found to occur in the oppositedeaved stage that it seems fair to assume 

 that further experience will show that it may occur in very many more — perhaps in 

 all species. 



Naudin's First Memoir, 347 (1883) says, after speaking of the adventitious 

 leaves " which take on the appearance of the juvenile stage. . . ," " this 

 retrogression towards anterior forms, and which is like a partial rejuvenation of the 

 tree, is not an obstacle to the flowering; these branches of juvenile aspect sometimes 

 flower and ripen the fruits as well as those of the adult form." He seems to have been 

 the first botanist who made this observation. 



In 1906 Dr. L. Diels published his " Jugendformen und Bliitenreife im 

 Pflanzenreich," and I cannot do better than quote portions of a review of it by C. R. 

 Barnes which appeared in the Botanical Gazette, vol. 45, p. 137 (February, 1908). The 

 work deals, inter alia, with the cmestion of precocious blooming, and the genus Eucalyptus 

 is illustratively employed. 



An interesting discussion of the relations between the vegetative form and the flowering period of 



plants is presented by Dr. Diels. . . . The questions with which the book deals were raised by the 



aut'ior's travels in West Australia in 1902. After his return he examined the literature, and made further 



inv.vsfcigatioiM to throw light upon the problems of form in the plant kingdom. He has gathered together 



C 



