50 BOOKS AND CURRENT LITERATURE 



rtiamillosa were found able to resume growth after an exposure of forty- 

 eight hours, while plants living lower on the shore were unable to with- 

 stand a single hour of exposure. Desmarestia aculeata, Alaria valada, 

 and Sarcophyllis californica were representatives of this latter group. 

 Intermediate forms, occurring midway on the rocks, will withstand 

 two hours of continuous desiccation; among these are Rhodomela 

 larix and Colpomenia sinuosa. While it is not claimed b^ the writer 

 that the ability to withstand desiccation is the only reasoti why some 

 algae grow high on the rocks and others are limited to the regions near 

 the low tide line the data show conclusively that drought is one of the 

 reasons why some forms at least can not grow in places where they will 

 be subjected to long exposure. 



The description of a new species* of green alga from the region of 

 the Puget Sound Station is recorded in another number of the publi- 

 cations. Frye and Zeller describe the form as differing from the other 

 species of the genus in the possession of gametes having four cilia 

 instead of two as in forms previously studied. This modifies our con- 

 ception of the genus. The new form, Hormiscia tetraciliata, is nearest 

 to H. collabens (Ag.) Rabenh. and H. incrassata (Kjellm.) Collins, but 

 has larger cells than either of these. It has been referred to H. worms- 

 kjoldii (Mert.) Fries, but differs from that species in having much 

 ♦narrower filaments. The plant was found at several places in the 

 vicinity of the Puget Sound Station. — R. B. Wylie. 



Osmotic Peessure in Saprophytes and Parasites. — G. Senn^ de- 

 termined the concentration of the sap of a number of plants from 

 Java cultivated in localit}^ and conditions not described, and found that 

 thick-leaved epiphytes were not higher in turgidity than terrestrial 

 species of the same region, while the sap of thin-leaved species was 

 distinctly more concentrated. An estimation of the relative concen- 

 tration of such parasites as Viscum, Orohanche, and Pedicularis and their 

 hosts gave a higher concentration of sap in the parasites of 0.025 to 

 0.625 Mol. K NO3, the lower figure being equivalent to less than 3.5 

 atmospheres. The relative concentration of sap of host and parasite 

 has received some attention experimentally, but the author comfort- 

 ably confines himself to a citation of the articles published in Jena. — 

 D. T. MacDougal. 



* Frye, T. C, and Zeller, S. M., Hormiscia tetraciliata sp. now. Pub. Puget 

 Sd. Marine Sta. 1: 9-13. January, 1915. 



' G. Senn, Der osmotische Druck einiger Epiphyten und Parasiten. Verh. d. 

 Naturforsch. Gesell, v. Basel. 24: 179-183, 1913. 



