1920] CURRENT LITERATURE 271 



tions to the antarctic regions. These have appeared from time to time in the 

 report of Skottsberg and others, and many have been noted in this journal. 5 

 The more recent reports have contributed to our knowledge of the vegetation 

 of the portion of South America and adjacent islands between 48 and 56 S. 

 Here is a rain forest covering a limited area, and composed of trees of low 

 stature, few exceeding 10 m. in height. The conspicuous species include 

 Nothojagus betuloides, Drimys Winteri, Pseudopanax laetevirens, and Libocedrus 

 tetragona, the only conifer reaching Fuegia. In unforested areas dwarf shrubs, 

 many from the heath family, and cushion plants are conspicuous. 



Farther to the north the Valdivian rain forest occupies the region between 

 the coast and the Andes, forming in the lower passes of the mountains a transi- 

 tion to the deciduous forest of the east slope. Between 41 and 44 S. a forest of 

 Libocedrus chilensis is interposed between the rain forest and the deciduous. 

 Many other formations are characterized, such as the pampas area east of 

 the Andes, the alpine heaths and meadow r s, the tussock grass and the tundras. 

 The bibliography includes 23 articles. — Geo. D. Fuller. 



Influence of environment on form and structure. — Folsam 6 reports a 

 study of the effects of 5 different degrees of soil water supply upon the struc- 

 tural features of Ranunculus sceleratus and R. abortivus. Plants were grown as 

 pot cultures in a greenhouse. Water w r as supplied in amounts varying from 

 complete submergence of soil and plant, to only enough soil moisture to sup- 

 port life. In the 24 which were studied 6 structural characteristics of R. 

 sceleratus gave consistently larger values with progressively greater water 

 supply in the first generation of plants. In the second generation, 2 of the 

 6 characters continued to show the same relation. They w r ere (1) thickness of 

 stem cortex, and (2) thickness of stem aerenchyma, both absolute and relative 

 to cortex thickness. In the first generation 5 structural features of R. abor- 

 tivus were found to be related in the same way to water supply. Of these the 

 one relation of increased laminar area of root leaves with increased water 

 supply was shown, although less consistently in the case of R. sceleratus. A 

 third generation of the latter species was grown to determine whether the 

 conditions of water supply of parent affected the laminar area of root leaves 

 of progeny grown both as xerophytes and as amphibians. Seeds for this 

 generation were obtained from the xerophyte group of the first generation, 

 and from the amphibious group of the second generation. Progeny grown 



with a large water supply gave consistently increased laminar area of root 

 leaves over plants grown with a small water supply, regardless of water rela- 

 tions of parents. — J. M. Arthur. 



5 Bot. Gaz. 58:96-98, 190. 1914; 63:423. 191 7. 



environmen 



water supply, upon 

 1918. 



209-2 



