218 Floristik, Geographie, Systematik etc. 



whole the previously isolated phenomena of plant structure, so the 

 evolutionary study of plant associations has shown that what have 

 been regarded as separate entities are often merely stages in de- 

 velopment. Schimper's 'edaphic formations' are rarely stable, but 

 tend to develop into the more stable 'climatic formations'. The 

 author suggests the use of the terms 'proximale' and 'ultimate' as 

 better implying evolution, the ultimate formation corresponding to 

 Schimper's climatic formation. It is probable that succession does 

 not take place where there is no essential change in external con- 

 ditions. The simplest and most important changes that bring about 

 succession are those which occur where the topography is stable 

 and are associated with the plants themselves. Amongst these 

 changes are humus accumulation and the influence of increasing or 

 decreasing shade. The ultimate formation of any upland will be 

 composed of those plants that can germinate in the densest shade 

 that ma}»^ there exist. An increase of shade is also accompanied by 

 increasing humidity and soil moisture thus working in harmony 

 with the humus factors. Plant invasions influence succession inas- 

 much as new elements are introduced, and the influence of man on 

 succession is very considerable. Typographie changes, such as 

 erosion or deposition by wind or water are also important. Changes 

 in general climate must influence succession, but such changes are 

 slow. Succession has thus many causes, and it is probable that 

 further study will increase the complexity. W* G. Smith. 



Gross, B. D., Some New Zealand Halophytes. (Trans. N. 

 Zealand Inst. XLII. p. 545—574. ill. 1910.) 



The district examined was the river Avon and its tributaries 

 near Christchurch. The formations are: 1) salt marsh with 

 Leptocarptis sbnplex, Jimcus mavithnus, etc.; 2) salt meadow with 

 Salicornia australis and Selliera radicans; 3) brackish water in Chan- 

 nels with Plagianthus divaricatiis, etc. The species, 16 in number, 

 taken from various localities are described first as to life-form, then 

 as to anatomy, The notes on life-form indicate briefly the external 

 features and adaptations of each species; in some cases illustrations 

 are given. The anatomical part deals with 12 species, in most cases 

 illustrated to show leaf structure. Several of the halophytes were 

 grown under ordinary garden and greenhouse conditions. In the 

 greenhouse all except Salicornia grew luxuriantly and provided 

 material for comparison with those grown in halophytic conditions. 

 In summarising the external features, the authoress refers to pro- 

 strate habit, reduction of leaves in number and size, thickness and 

 translucence of leaves, and bright colouration of vegetative organs. 

 Anatomically the cuticle is uneven, glandulär hairs are present, the 

 stomata are large; the mesophyll has strong palisade tissue, reduc- 

 tion of intercellular Spaces, and in some cases a definite water- 

 storing tissue. As to the origin of halophytic formations, it is held 

 that the characters observed are those of xerophytes. Cockayne's 

 view is supported that halophj^tes are inland plants driven by com- 

 petitors from the more hospitable ground , and that they occupy their 

 haloph)'^tic stations not from choice but from necessit5^ 



W. G. Smith. 



Domin, K., Eine kurze Uebersicht der im Kaukasus hei- 



