24 ECOLOGY, PLANT GEOGRAPHY [Bot. Absts., Vol. IV, 



182. Church, A. H. The plankton-phase and plankton-rate. Jour. Botany 57: Suppl. 

 III. 1-8. 1919. — The term plankton was proposed by Victor Hensen in 1887 for the floating 

 population of the sea, and has become a fundamental conception of the greatest biological 

 interest. The author deplores the extension of the term to limits not originally intended. 

 The subject is degraded by its application to "Limnoplankton" of a pond, "Saproplankton" 

 of dirty water or such curious expressions as the Cryptoplankton of algae found in snow. 

 Plankton is more physiological than morphological, and relates to the problem of the food 

 supply of the sea. Free unicellular forms of plant life are about all that is left under the term. 

 The amount of such organic life is very great. Gran recorded 5-6 million per liter in milky 

 water of Christiania Fjord. Generally, maximum plankton content occurs where coastal 

 waters bring down land-debris. The deep blue of the ocean indicates a poor flora and fauna. 

 In a liter of Kiel Bay water Lohman found a total of over 2£ millions of organisms. — The plank- 

 ton represents the oldest life on the planet, occurring as it did in the sea before benthic life 

 began. Higher organisms still retain a plankton phase in their life history, which is a kind of 

 recapitulation of their race history. To such a phase belong ovae, spermatozoids, gametes 

 of all kinds, and spores. In the Siphonogamia and a few fungi alone is the plankton stage 

 practically eliminated. — We may visualize the plankton rate as expressed by the amount of 

 cytoplasm in one million zoids per liter. With such a unit, quantities of plankton often dis- 

 similate in nature may be compared. A fair plankton rate may about equal the ionization 

 of water; but there is no causal relation, since the mass of water can replace the ions, while 

 the plankton is limited by scarcity of nitrogen and phosphorus. In the Sargasso Sea, the 

 sea-weed uses most of the available N. and P. ions, and plankton life is thus very much re- 

 duced. However, the factors determining the amount of plankton a sea can carry are yet 

 obscure. While of no exact scientific value at present, such considerations as the "mean 

 plankton-rate" may be useful in establishing some general basis for the consideration of the 

 phyto-plankton and phytobenthos of the British coasts. A bibliography is appended. — 

 K. M. Wiegand. 



183. Dufour, Leox. Les stations du Physomitra esculenta dans la foret de Fontaine- 

 bleau [France]. [Stations of Physomitra esculenta in the forest of Fontainebleau.] Bull. 

 Trimest. Soc. Mycolog. France 35: 142-143. 1919. — The author comes to the conclusion that 

 two principal conditions seem to be necessary for this fungus. (1) a stand of pine-trees; and 

 (2) a large amount of air and light. — Fred C. Werkenthin. 



184. Fuller, George D. Maps of rainfall and crop plants. [Rev. of: (1) Kincer, 

 Joseph B. Atlas of American agriculture. Advance sheet 1 : Precipitation. U. S. Dept. 

 Agric. Weather Bureau 1917; and (2) Finch, V. C, and O. E. Baker. Geography of the 

 world's agriculture. 10X13.5 inches. 149 p. 207 fig. 1917.] Bot. Gaz. 67: 102-103. Jan., 

 1919. 



185. Ginzberger A. Beitrage zur Naturgeschichte de Scoglien und Kleineren Inseln 

 Suddalmatiens. [Natural history of the "Scoglien" and smaller islands of southern Dalmatia.] 

 Denkschr. K. Akad. Wiss. Wien (Math.-Nat. Kl.) 92 : 261-405. PI. 1-8. 1916— This contains 

 a chapter on fungi by K. v. Keissler, one on lichens by A. Zaiilbruckner [see Bot. Absts. 4, 

 Entry 2557], one on mosses by Julius Baum GARTNER, one on liverworts by V. Schiffner [see 

 Bot. Absts. 3, Entry 1589], and one on higher forms by A. Blrgerstein. — H. M. Fitzpatrick. 



1S6. Gleason, H. A. What is ecology? Torreya 19: S9-91. 1919.— Ecology is defined 

 as the accumulation and organization of knowledge concerning the correlation between the 

 plant and its normal environment. It is often confused with morphology and physiology. 

 These deal only with the structure and behavior of the plant, while ecology should consider 

 these solely in correlation with the environment. — /. C. Nelson. 



187. Harper, Roland M. A new method of mapping complex geographical features, 

 illustrated by some maps of Georgia. School. Sci. Math. 18: 699-70S. 4 fig. Nov., 191S. — 

 Author describes "a quantitative regional method" of mapping features such as soils, vege- 



