Physiologie. — Cryptogamen im Allgemeinen. — Algen. 41 



renchyma divides and grows so as to occlude the intercellular 

 Spaces: an absciss-layer is formed along the line of occlusion, 

 by means of which the injured tissue is isolated, when the 

 absciss-layer gives rise to several layers of cuticularised cells 

 forming a callus. 



The above results were obtained in the laboratory. When 

 similar injuries were inflicted upon leaves still attached to the 

 plant in the open, no such exfoliation of the injured parts took 

 place: occlusion-tissue was formed, and eventually cork-layers, 

 but no absciss-layer. 



The authors conclude that the determining factor of the 

 mode of reaction is the degree of moisture of the air. When, 

 as in the laboratory-experiments, the injured leaves are in a 

 moist atmosphere, the object of the healing reaction is to get 

 rid of the dead tissue; whereas when the atmosphere is dry, 

 the object is to protect the healthy tissue from desication as 

 quickly as possible. The observations make it more than ever 

 difficult to distinguish between „callus" and „wound-cork". 



S. H. Vines. 



Small, J. K., The flowerless plants (Cryptogams) o f the 

 synoptic collection. (Journal of the New-York Botanical 

 Garden. IL p. 81—87. PI. VI— VII. June 1901.) 



Account of the Cryptogams displayed in the Museum of the New- 

 York Botanical Garden. " " Trelease. 



Schuh, R. E., Further notes on Rhodlnocladia. (Rhodora. 



III. p. 218. Aug. 1901.) 



Redescription of a genus allied to Desinotriciinm, described in the 

 same Journal /or June 1900, with description of the original species, 

 R. Farlowü and a new species, R. cylindrica. — both from the lower 

 New England coast. ' Trelease. 



CoLLlNS, F. S., Notes on Algae. III. (Rhodora. III. p. 132 

 — 137. May 1901.) 



Critical and distributiona! notes on Protoclerma marinum, Plecto- 

 netna Nostoconim . Ectccarpus fasciculatus abbreviatiis, Elachista Chondri, 

 Actinococais aggregatiis, Melobesia Corallinne, Ralfsia Borneti, Mono- 

 stroma latissimnni, CalUthamnion tetragonnm and Lomentaria rosea; and 

 descriptions oi two new species: Isactis centrifiiga Bornet and Pleiiro- 

 capsa crepiäiniim Collins, the former from Rhode Island and the latter 

 from Maine. Trelease. 



HoWE, M. A., Observations on the algal genera 

 Aciciilan'a and Acetabiilum. (Bulletin of the Torrey Botani- 

 cal Club. XXVIII. p. 321—334. PI. 24—25.) 



From a developmental study, made on material of Acl- 

 ciilaria Schenckii collected by the author in Bermuda, the 

 views of Solms-Laubach on the morphological homologies 

 of the disc and its parts are in the main accepted, namely that 

 the disc is not a complicated , aggregation of whorls of 

 primary branches and the sporangia are, with little doubt, 



