1902] CURRENT LITERATURE 377 



Thomas ; Notes on apple rusts, and Notes on the genus Stemonitis, by H. H. 

 Whetzel ; The plant ecology of Winona lake, by Lucy Youse. The sec- 

 retary of the Academy is John S. Wright, Indianapolis, Ind. — J. M. C. 



NOTES FOR STUDENTS. 



Students of stem anatomy will be interested in a recent paper of 

 Solms-Laubach* upon the branching of Isoetes lacitstris. The occurrence of 

 a large number of branching specimens of unusual luxuriance and size, in a 

 lake visited by the author in 1897, led him to a detailed study of the stem and 

 a review of the literature upon the subject. — Florence M. Lyon. 



Tobler3 finds that the thallus of one of the Rhodomelaceae, namely 

 Dasya elegatts^ breaks down into single cells and cell-groups under certain 

 conditions, and that these cells retain their vitality and finally develop new 

 thalli, after the manner of the process which occurs so often in the Con- 

 jugatae and Confervoideae, The exact conditions under which this breaking 

 down occurs were not worked out, but the author is sure the active stimulus 

 is not one of increase in concentration of the external solution. 



Observation that the ultimate branches of Bryopsis phonosa fall off and 

 exhibit a marked power of growth somewhat similar to that just described, 

 and that they sometimes form long siphonaceous tubes much resembling 

 those of Vaucheria, has been made by Wright* and recorded in a recent note. 



— B. E. Livingston. 



Two FUNGUS DISEASES of the white cedar {Cttpressiis thyoides) are 

 described in a recent paper by Harshberger.^ These are caused by Gy??inO' 

 sporangium biseptatnm Ellis, and G, Ellisii (Berk.) Farlow, both of which 

 grow in the wood of the cedar. The author discusses the normal structure 

 of the cedar wood, paying special attention to the number of tracheids in the 

 various- annual rings, and the conditions which influence their development. 

 The influence of the growth of the fungus mycelia in the stems is evidenced 

 by the formation of swellings, which show a large increase in the number of 

 tracheids and increased activity of the phellogen. In the swellings caused 

 by G, biseptatuniy many of the tracheids appear to be plugged by a substance 

 which the author calls ** fungus gamboge." A detailed description of the 

 structure of the swellings, the mycelia, and a consideration of the relation of 

 the host cells and the hyphae follow.— H. voN Schrenk. 



'Solms-Laubach, H. Graf zu, Isoetes lacusiris, seine Verzweigung und sein 

 Vorkotnmen in den Seen des Schwarzwaldes und der Vogesen. Bot. Zeit. 60:179- 

 206. pi. 7. 1902. 



3TOBLER, F., Zerfall und Reproductionsvermogen des Thallus einer Rhodome- 

 lacee. Ber. Deutsch. Bot. Gesell. 20:357-365. 1902. 



^Wright, E. P., Note on Bryopsis plumosa. Notes from Bot. School Trin. Coll. 

 Dublin. 1:174-175. 1902. 



5 Harshberger, John W., Two fungus diseases of the white cedar. Proc. Acad. 

 Nat. Sci. Philadelphia, 1902: 461. 



