DER EINFLUSS DES KLIMAS 309 



tion ; and he even instances Salicornia herbacea to support his 

 view ! 



These examples suffice to show the unconvincing nature of the 

 book, which continues with consideration of the vegetation of the 

 solfataras, sea-shore, inland forests, patanas, parasites, and epi- 

 phytes, among which are isolated facts that are both interesting 

 and new. (Incidentally a novel view of priority is taken when 

 Mr. Boodle's already published observations on Pteris are quoted 

 as subsequent to the author's, and later a similar original concep- 

 tion is brought out in reference to Mr. Wright's suggestive work on 



leaf-fall.) 



Upon leaf-fall and periodic growth in thickness of wood, Prof. 

 Holtermann adds nothing, so far as the reviewer can see, novel in 

 idea or in fact. He records a pretty observation made by Mr. 

 Carruthers, who noted that a chocolate-tree seven years old showed 

 twenty-two rings of growth and had cast its leaves thrice a year. 

 Prof. Holtermann, in reference to the production of wood-vessels 

 at the beginning of the vegetative season in tropical trees, adopts 

 the familiar theory put forward by Hartig in connection with 

 temperate trees ; but he restates it (in spaced type) in manner too 

 narrow and dogmatic, thus : " At the commencement of the vege- 

 tative season it is absolutely necessary for new conducting chan- 

 nels to be produced rapidly, since the tracheal elements, which 

 sufficed for the old leaves, are no longer sufficient, because the 

 transpiration has materially increased. In addition the branches 

 commence to grow, and in a very short time the mass of foliage 

 is considerably larger than formerly." This proposition is nothing 

 more than an assumption, because it neglects two facts : first, the 

 amount of water stored in the wood of the tree ; secondly, the possi- 

 bility that the tree may perhaps, by increased rapidity of current, 

 temporarily do without any sudden increase in channel. Later on, 

 Prof. Holtermann makes an astounding misstatement in reference 

 to a suggestion due to Hartig, to whom he attributes the opinion 

 that there is "a connection between the formation of annual rings 

 and the production of heart- wood"; and then he laboriously pro- 

 ceeds to overthrow this obvious delusion. Hartig, of course, never 

 sought to establish any such relation, but he did show that those 

 temperate trees which produce heart-wood, and in which the con- 

 ducting channel consists of a few annual rings, the so-called 

 "spring zone" is especially porous, and did ingeniously suggest 

 that this is due to a sudden call for water-conducting elements. 



In the final Section dealing with M Direct Adaptation," we find 

 at the outset the same peculiar perspective in regard to the work 

 of other botanists. In opening the discussion on the effect of 

 changed habitat on haloph\ tes the author has to agree in results 

 with Schimper, yet without any justification he suggests (once 

 more in spaced type) that certain of Schimper's observations on 

 Sonneratia acid a were possibly not made on that plant at all. 

 Again, in reference to Schimper's statement regarding stone-cells 

 in Sccevola Koenigii, he says, " I cannot definitely contradict this 

 assertion," and adds that he could not find stone-cells in tins 



