46o BOTANICAL GAZETTE [December 



Lepidophyllum. These chapters are followed by a discussion of the floristic and 

 ecological relationships of the plants, a table of the species with ample taxonomic 



formations 



Henhy C. Cowles 



Galvanotfopism again.^Miss Bayliss,^ working at Birmingham under the 

 direction of Ewart, has studied the effect of electric currents applied directly to 

 roots by electrodes, polarizabie and non-polarizable, and indirectly by imbedding 

 seedlings in a 3 per cent, gelatin solution between platinum electrodes 10-12*="^ 

 apart. The currents used were 4.2 volts with the resistance that of the gelatin 

 for 48 hours, or of the roots alone (3-8 minutes), or 150,000 ohms, applied for 

 5 to 48 hours, or 220 volts with 2220 ohms applied for 50 seconds. She finds 

 that it makes a difference where the electrodes are placed; when on opposite 

 sides of the sensitive (growing) region the curvature is always toward the cathode, 

 but if one is nearer the apex than the other the curvature is toward the apical 

 electrode. Unhke Plowman'^ whose papers she has overlooked, she found that 

 curvatures could be produced without injur}% even by strong currents of short 

 duration. Contrary to Gassner, whose mode of experimentation she deprecates; 

 she concludes that the curvatures are due to the ions produced by electrolysis 

 and that galvanotropism therefore is a form of chemotropism, and not neces- 

 sarily of traumatropism. — C. R. B. 



—E-bhedra distachva has been studied recently by 



Embryogeny in Ephedra. — Ephedra distachya has 

 Miss Berridge and Miss Sanday,^ who find two markedly unequal male nuclei 

 lying in a common cytoplasmic mass. The functioning male nucleus 

 slips out of the cytoplasmic mass and passes to the egg nucleus. Although no 

 case of fusion was observed, fertilization is thought to occur because proembryos 

 are found which the authors can account for in no other way than by supposing 

 fertilization has occurred. The jacket cells arise at the same time as the central 

 cells. Later the nuclei of the jacket cells divide by direct division, the binucleate 

 cells enlarge and become gorged with food, and the wall of the egg breaks down, 

 permitting the jacket nuclei to escape. The jacket nuclei fuse in pairs within 

 the egg and give rise to proembryos. In some cases the proembryos are merely 

 enlarged jacket cells, proembrj'onal cells occur within jacket cells not adjacent 

 to archegonia, and migration and fusion of the nuclei of neighboring jacket cells 

 precede the formation of these proembryos. These are startling claims to 

 make in connection with the embryogeny of a gymnosperm.— W. J. G. Land. 



Items of taxonomic interest. ~N. C. Kindberg (Rev. Bry. 34:87-92. 1907), 

 in notes on North American mosses. ha.s described new sneries under Pseudo- 



Dichodontium, Grimmia 



rVYLISS 



Annals of Botany 2 1 : 



387-405, figs, 6. 1907. 



^ 9 Berridge, Ethel M., and S.vstday, Elizabeth, Oogenesis and em 

 in Ephedra distachya. New Phytologist 6:128-134, 167-174. pis. 3,4. 1907 



