REVIEWS. 545 



Dingier. H. Uber Periodizitat sommergruner Baume Mitteleu- 

 ropas im Gebirgsklima Ceylons. Sitzungsberiehte der Koniglich 

 Bayerischen Akademie der Wissenschaften, &c., Jahrgang 1911. 



Professor Dingier, who visited Nuwara Elija in 1910, has 

 recorded his observations on the much-debated question of 

 the behaviour of the deciduous trees of temperate climates 

 when transferred to the hill regions of the tropics. He deals 

 chiefly with two of the species of oak at Hakgala, Quercus 

 pedunculata and Q. cerris, as well as with Fagus silvafica, 

 Castanea vesca, Betula alba, Populus pyramidalis, Platanus 

 acerifolia, and the fruit trees, pear, apple, cherry, and peach. 

 He recognizes that definite conclusions on the matter cannot 

 be attained without continuous observations for several years 

 on the behavioiu- of selected specimens, and has attempted 

 to remedy this deficiency (1) by examining material collected 

 subsequent to his visit and forwarded to him in Europe, and 

 (2) by obtaining the opinions of residents on times of leaf -fall, 

 fruiting, &c. But such opinions are merely general impres- 

 sions, and they are scarcely worthy of the credence which 

 Professor Dingier gives them, especially when they relate to 

 species which are never, or very rarely, entirely leafless. 



The observations on Quercus pedunculata relate to the 

 scrub oaks in front of the laboratory at Hakgala. A com- 

 parison of the older trees would not have revealed so muc-h 

 difference between this species and Q. cerris as Professor 

 Dingier supposes. The suggestion that the leaf-fall of these 

 Q. pedunculata is correlated with the dry months of February- 

 March is not in accordance with fact ; in these months the 

 trees are covered with new leaf. Again, the remark that the 

 pear and the apple behave alike mast be qualified by the 

 information that the former (a cooking variety) produces fruit, 

 while the latter, in general, does not. 



The distinction between the oaks at Hakgala and that at 

 Nuwara Eliya, based on the supposed difference of origin of 

 the two trees, is of doubtful accuracy, for, in the absences of 

 any definite record, it is most probable that the Nuwara Eliya 

 oak was transferred there from Hakgala. 



One circumstance which may affect the periodicity of 

 certain of these Hakgala trees has escaped the notice of 

 Professor Dingier and other observers. The scrub oak at 

 Hakgala is always, at least since the year 1904, severely 

 attacked after each monsoon by a mildew (oidium), whu-h 

 does not attack Q. cerris. Similarly, the peach trees suff.-r 

 great damage from the attacks of Exoaacus deformana and 

 Uredo pruni. 

 Engler, A. Das Pflanzenreich. Leipzig. 1900 (in progrees) 

 (continued from Annals, Peradeniya, Vol. HI., p. 93). 



11 Heft. Marantace^ by K. Schumann Of the tlirc-c- 



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