V 





1917] CURRENT LITERATURE 415 



The last chapter deals with the dominant group of the region, the Brome- 

 liaceae. The 2 main divisions considered are the cistern plants and the epi- 

 phytic Tillatidsias. The latter are divided into those which lean against the 

 support and those having some means of attachment to it. The different 

 adaptations for climbing are illustrated. The structure and function of 

 the hairs of Tillandsia and of the hairs on the submerged leaf bases of the 

 cistern species are given particular attention. The presence of cortical roots 

 in the attached lianas is also noted and their value to the plant discussed. 

 Here, as in the Solanaceae, insect pollination is not very common, but the 

 humming bird is a regular visitor to some large-flowered species. A few of 

 the Bromeliaceae, as Tillandsia usneoides and T. recurvata, have a range from 

 southern United States or Mexico to the southern part of South America. 

 Most of the species mentioned, however, are limited to South America, 9 being 

 given as endemic. The author also includes in this chapter a very interesting 

 description of the xerophytic rupicole species belonging to various families 

 which are found on the rocks of Cerro San Tomas and Sierra d'Acahay. — 

 Ak a villa Taylor. 



NOTES FOR STUDENTS 



Puget Sound algae. — A fascicle of papers 2 from the Puget Sound Marine 

 Station at Friday Harbor, Washington, gives the results of work done on 

 algae at the station, largely during the summer of 1916. 



Miss Hurd finds that young bladder kelps (Nereocystis) can adapt them- 

 selves to 55 per cent of fresh water in their environment if the change is made 

 gradually. She concludes that rapid elongation of this plant is due to low light 

 intensity in the water, and that growth of the stipe is greatly retarded by 

 strong light when the bulb approaches the surface of the water. The fact that 

 this does not act as a very exact determiner of length is readily understood, 

 when we remember that the variation from extreme high tide to extreme low 

 tide during the growing season in this region is more than 12 ft. She reaches 

 the conclusion that there is no relation between rate of growth and mechanical 

 stretching in the stipe of the plant. The experimental evidence given seems to 

 justify this conclusion, providing that nothing else (for example, light) was 



a limiting factor in both exneriment and control. 



adhaerens 



J 



Sound is C. dimorphum Sved., since it has no utricle hairs and has two types 

 of utricles, the one with unmodified end wall and the other with thickened, 



striated end wall. 



predominance 



thick or of thin end walls in the utricles is probably due to differences in envi- 



ronment. The thick-walled type sometimes 



2 Puget Sound Marine Station Publications i:nos. 17-24. 185-248. pis. 33-466 





1916. 



