BOTANICAL GAZETTE [jantjary 



The second part of the volume presents a detailed account of the most impor- 

 tant families of vascular plants and their representatives, the vegetation forms, 



formations 



Among the 



(Nothofagu 



more inici^^»-iii5 v^» M — - 9 



soecies are deciduous and three evergreen, and the conifers (Araucana and Fitz- 



roya); 1 

 swamps 



the 



forms 



These conifers and beeches sometimes form pure forests, but most of 



Other important formations are 



the bamboo (Chusquea) thickets, xerophytic acacia thickets, and steppes. 



The most detailed portion of the volume is that presenting the floristic fc<* — . 

 of the Chilean vegetation from north to south, and the delimitation of floral prov- 



Many endemic species and monotypic genera are found in the country. 



inces. 



The final chapters consider the relations of the Chilean flora to other floras 

 (notably those of California, New Zealand, and Argentine), the life-history of the 

 Chilean flora, and the modifications due to human influence. From the develop- 

 mental standpoint the flora is made up of (i) a tropical contingent, the oldest of 



Mesozoic: (2) the Andine 



associated with the rise of the Cordilleras; (3) the Calif ornian and Mexican con- 

 tingent; (4) the Antarctic contingent, mostly in southern Chile, and related to 

 the New Zealand flora; (5) the boreal contingent, perhaps the most interesting 

 of all, there being genera and even species in southern Chile that are common with 

 the far north; (6) ubiquists and littoral pantropists; and (7) adventives. Many 

 admirable plates add much to this important volume.— H. C. Cowles. 



The pendulation theory 



Permian 



the tropics by supposing that the poles have shifted their position during the 

 course of geologic history. Such theories are usually dismissed because they mtro- 



difficulties 



Reibisch 



fur Erdkunde at Dresden such a theory, known 



Smroth 



Leipzig a detailed account of the theory, together with a new alignment of facts 

 of distribution. The essence of the pendulation theory is that the earth swings 

 slowly to and fro upon an axis whose poles are in Ecuador and Sumatra. 1 ^ es 

 poles are supposed to remain fixed, but the axial extremities that we commonly ca 

 the north and south poles are such for but a moment, speaking geologically. 

 It will be seen that Ecuador and Sumatra must have been in the equatorial realm 



points 



fixed pol 



of Samoa), there may have been in times past any conditions between po 



3 Simroth, Heinrich, Die Pendulationstheorie. pp. xii + 564. maps 27. ^ e r 

 zig: Konrad Grethlein's Verlag.] 1907. Mi 2. 



