154. BOTANICAL GAZETTE [august 



The results for Chylocladia are especially interesting, since they flatly contra- 

 dict the conclusions of Hauptfleisch (Flora 75:306. i8q2). The latter 

 described a number of secondary cell and nuclear unions following the 

 sexual act and resulting in a large fusion cell, Hassenkamp seems to have 

 overlooked a paper of mine (Box. Gaz. 21 : 109. 1896) which showed that 

 Haupifleisch's results for Champia, a genus closely related to Chylocladia, 

 were incorrect. This omission is the more conspicuous since Oltmanns 

 (Bot. Zeit. 56: 128. 1898) tried to smooth over the grave errors of Haupt- 

 fleisch by assuming that we were not dealing with the same form, Champia 

 probably presents the same conditions as Chylocladia, as may be judged by 

 comparing my figures with Hassenkamp's. — B. M. Davis. 



KoHL^^ describes an accurate method of measuring the expansion and 

 contraction of pith cylinders, etc., when placed in solutions of different con- 

 centrations. The object to be studied is fastened upright by its base in a 

 suitable chamber provided with entrance and exit tubes for the application 

 and changing of plasmolyzing solutions. To the upper end of the object is 

 attached a thread which travels over two small pulleys at the same height 



■ 



and some distance apart. It is sufficiently weighted at its other end to remam 

 taut, and bears a pointer between the pulleys. This pointer traverses a 

 fixed horizontal scale which furnishes a means of measurement, 



■ 



In the same paper is described a new form of self-registering auxanometer 

 which the author designates 2l% photographic. A revolving cylinder, covered 

 with a sensitized collodion film, is enclosed in a dark box, in one of whose 

 sides is a vertical strip of metal provided with an opening of i ^'^ diameter. 

 This strip is long enough to allow vertical movement without admitting light 

 excepting through the opening. A minute incandescent lamp is fixed to the 

 strip in such a manner that the rays from the lamp traverse the opening at 

 right angles to the strip, and impinge upon the revolving film within the box. 

 By means of a filament passing over a wheel the sliding strip may be fixed 

 to any object whose upward movement is to be studied. As this rises the 

 beam of light moves downward over the film, which, of course, will need to 

 be developed in the usual way to bring out the record. — B. E. LiviXGSTON, 



Edward C. Jeffrey^s has published a paper entitled "The structure 

 and development of the stem in the Pteriodophyta and Gymnosperms." The 

 author reaches the following morphological conclusions : There are two types 

 of cauline central cylinder, protostelic and siphonostelic ; the protostehc 

 central cylinder is more primitive, and in its single concentric vascular 

 strand no medulla is present; the siphonostelic central cylinder is tubular, 



=*KoHL, F. G., Ein neuer Apparat zur Demonstration von Wachstums una 

 Plasmolyse-Erscheinungen. Ein photographisches Auxanometer. Ber. Deut. Bot. 

 Gesells. 20 : 208-212. 1902. 



^5 Phil. Trans. Roy. Soc. London B. 195: 119-146,//?. i-b. 1892. 



