June 26, 1914] 



SCIENCE 



947 



Lancaster County " (Penn.) and now we must 

 add two more similar books to his credit. They 

 are the " Flora of the Florida Keys " and the 

 " Shrubs of Florida " both of which appeared 

 within the last few months. The first is a neat 

 little volume of about 160 pages containing 

 descriptions of the seed plants growing nat- 

 urally on the islands of the Florida reef from 

 Virginia Key to Dry Tortugas, a distance of 

 about 225 miles. As the author remarks, " we 

 find here a tropical flora made up almost 

 wholly of West Indian elements, and closely 

 related to the floras of Bermuda, the Bahamas 

 and Cuba." To a northern botanist it seems 

 strange to find among the grasses no species 

 of Poa, nor of Bromus; in the sedges no spe- 

 cies of Carex; in Brassicaceae but four spe- 

 cies; in Rosaceae no species; while the legu- 

 minous families aggregate 57 species; Euphor- 

 hiaceae, 45 species; Malvaceae, 17 species, and 

 Rubiaceae, 22 species. Of the three families 

 of composites there are but 44 species. 



In the other little book (of 140 pp.) the 

 northern botanist will be astonished to find a 

 shrubby grass [Lasiacis (Panicum) divari- 

 cata'], a buckwheat (CoccoloUs) forming 

 " evergreen shrubs or trees," the Castor-oil 

 plant (Ricinus communis) " a small tree or 

 shrub," a shrubby heliotrope (Heliotropium), 

 and a low shrubby Eupatorium. Both books 

 will well repay careful examination. 



SHORT NOTES 



An interesting paper by Dr. W. B. Mc- 

 Dougal on " The Mycorhizas of Forest Trees " 

 appeared in the first number of the new Amer- 

 ican Journal of Forestry showing that in some 

 cases the relations between the tree and the 

 fungus is symbiotic and sometimes parasitic. 



Freda M. Bachsiann's paper on " The Origin 

 and Development of the Apothecium in Col- 

 lema pulposum " ^ is a valuable contribution 

 to the theory as to the phylogeny of the Asco- 

 mycetes propounded by Dr. E. A. Bessey,^ in 

 which he suggested that the first Ascomycetes 

 were lichens. In her paper Miss Bachmann 

 says " in the number and nature of its sperma- 



^Arohiv. fur Zellforschung, Band X., Heft 4. 



2 Mycol. CentralU., Vol. III. 



tia and in the manner in which they are borne, 

 Gollema pulposum forms about the most per- 

 fect conceivable connecting link between the 

 aquatic red algae with many non-motile male 

 cells which are, however, set free, and such 

 terrestrial ascomycetes as Pyronema and the 

 mildews where the male cells are reduced in 

 number to one or two which remain perma- 

 nently attached." 



A RECENT handful of papers from Professor 

 Doctor Aven Nelson reminds one of the taxo- 

 nomic activity of the director of the Rocky 

 Mountain Herbarium at Laramie, Wyoming, 

 and serves to show that there is still much to 

 be done in the systematic botany of the central 

 mountains of the country. 



Dr. 0. E. Jennings's " Manual of the Mosses 

 of Western Pennsylvania " (1913) should have 

 been noticed long ago, since it offers to botan- 

 ists in the central east a descriptive manual of 

 these plants accompanied by fifty-four full- 

 page plates of original drawings. The book in- 

 cludes somewhat more than four hundred 

 pages, and is a credit to the author, and the 

 institution (Carnegie Museum, Pittsburgh) 

 from which it is issued. All told more than 

 275 species and varieties are described. The 

 treatment is modern, the specific names being 

 decapitalized, and " the rulings of the Inter- 

 national Botanical Congress, held in Brussels 

 in 1910, have been followed." 



Charles E. Bessey 



The University of Nebraska 



SPECIAL ARTICLES 



CELL PERMEABILITY FOR ACIDS 



Since Overton's first extensive and well- 

 known studies and his publication of the 

 lipoid theory, interest in the subject of cell 

 permeability has continually increased. Al- 

 though adherents of the theory have modified 

 and supported it with subsidiary hypotheses 

 the two essentials remain unchanged to-day, 

 namely — (1) that substances which are most 

 soluble in lipoids (fat solvents or fat-like 

 bodies) enter living cells most readily and 

 (2) that they do so because they dissolve in 

 the cell surface which is lipoid in nature. 



