igoS] CURRENT LITERATURE 359 



Nutrition of aquatics. — A new investigation of this subject has been pubhshed 

 by Snell.^^ So far as the author's experiments overlap those of the reviewer, 

 there is perfect agreement in the conclusion that aquatic plants rooted in the soil 

 take nourishment therefrom, and that the roots function as regular organs for the 

 entrance of food substances. In the case of Pistia Stratiotes the roots, though not 

 attached to the soil, still function as roots in allowing food substance in the water 

 to enter. The roots of Lemna, however^ serve only to balance the plant. Some 

 results were obtained which do not agree with those obtained by the reviewer, 

 the value of which he is not willing to concede; but since the author docs not 

 regard the differences of enough importance to state them formally in the final 

 conclusions, further discussion is not necessar>\ — Raymond H. Pond. 



- A new pteridosperm. — Arber^^ has described a new Pteridosperm {Carpo- 

 lithiis Nathorsti) from the coal fields of Germany, from a specimen preserved in 

 the collections of the Swedish Academy at Stockholm. The seeds are extra- 

 ordinarily small, the average length being about i^"\ and the greatest width 

 0.75"^^. They are borne upon an undoubted sphenopterid frond, and were 

 probably inclosed in cupules. It is not certain that this seed is a true Lageno- 

 stoma, but it confirms strongly the habit of the fertile fronds inferred for the 

 species of Lagenostoma.— J. ^I. C. 



Wound tissues.— In a somewhat lengthy discussion of wound tissues resulting 

 from removing rings of cortex from twigs, Keieg-'^ finds that in plants growmg 

 in the sun greater masses of wound tissue are produced than in plants growmg 

 in the shade; and that in forms with larger leaves the callus above the ring is 

 much larger than that produced by small-leaved forms. — W. J. G. Land. 



Economy of chlorophyU proper.— Stahl suggests*" that the earlier disappear- 

 ance of the blue-green component of chlorophyll, leading to the yellowmg of 

 leaves in autumn (which is checked by preventing migration of materials from 

 the leaf or any part of it), as well as its later appearance in seedlings of etiolated 

 plants, is a matter of economy. — C R. B. 



37 Snell, Karl, Untersuchungen uber die Nahrungsaufnahme der Wasserpflan- 

 zen. Flora 98:213-249. 1907. 



3« Arber, E. a. Newell, On a new Pteridosperm possessing the Sphenoptens 

 type of foliage. Annals of Botany 22:57-62. ^/. (5. 1908. 



39 Krieg, August, Beitrage zur Kenntniss der Kallus- and Wundholzbildung 

 geringelter Zweige und deren histologischen Veriinderungen. pp. 68. pis. 23. Wurz- 

 burg: A. Stuber. 190S. 



4° Stahl, E.. Ueber das Vergilben des Laubes. Ber. Deutsch. Bot. Gesells. 



^5:530-534- 1907- 



