68 . BOTANICAL GAZETTE [july 



cultures primary mycelia were obtained which did not produce carpophores. 

 When parts of each mycelium were mixed in a culture, a secondary mycelium 

 appeared and fruit bodies were produced. The chief method of bringing 

 about the plasmogamy is through the union of a hyphal cell of one thallus 

 with an oidium from another thallus. Miss Bensaude concludes that the 

 "dicaryon" in C. fimetarius is formed following plasmogamy between ceUs 

 coming from 2 different thalli. 



The transformation of a primary mycelium into a secondary mycelium is 

 very difhcult to observe. This is brought about by the anastomosis of 2 

 hyphal cells of different thalli in C. fimetarius. The fusion of 2 such cells 

 (plasmogamy or pseudogamy) introduces the cytoplasm and nucleus or nuclei 

 of one cell into the other, which results in the establishment of a binucleate 

 ceU. If 2 cells unite which have more than 2 nuclei in common, all disintegrate 

 but 2. The uninucleate oidium may fuse with a hyphal cell, and this is a very 

 common means of bringing about the initial binucleate condition of the cell. 



Each ceU in these secondary hyphae is binucleate, constituting a 

 "dicaryon." Conjugate nuclear division occurs in these hyphae as a rule in 

 the apical cell, although intercalary cells divide occasionally. At the time of 

 division the 2 nuclei move to the middle of the cell, and the actual process of 

 cell division is preceded by the formation of a protuberance which is to form a 

 clamp. One of the nuclei, which Miss Bensaude calls (+), on the basis of her 

 results with single spore cultures, enters this very short branch, and the ( — ) 

 nucleus remains at about the same level in the mother cell. Spindles are formed 

 and conjugate nuclear division takes place. One of the (+) daughter nuclei 

 goes back into the mother cell, and the other goes to the apex of the young 

 clamp. A cross-waU cuts off the beak cell from the mother cell. Of the 2 ( — ) 

 daughter nuclei, one goes to the apical part of the mother cell and the other to 

 the basal part, and a cross-waU is formed at the level of the young clamp, 

 dividing the cell into an apical portion with (+) and ( — ) daughter nuclei 

 and a basal cell with only the ( — ) daughter nucleus. The little beak now 

 fuses with the basal cell, and its nucleus passes into this cell, so that it also 

 becomes binucleate. Very often the apex of the beak fuses with the mother 

 cell before nuclear division takes place. 



Reversion of secondary to primary mycelium occurs, in which case a 

 uninucleate cell appears among binucleate cells. No clamps are found on the 

 cross-walls of this cell, and these uninucleate cells may bear oidia. — Michael 

 Levine. 



A new conception of sex. — ^Jones'! presents a conception of sex which is 

 quite unorthodox, but at least it furnishes considerable food for thought. 

 This author sees in fertilization an "attack" of a "parasitic" male gamete 



* Jones, W. N., On the nature of fertilization and sex. Xew Phytol. 17: 167-188. 

 1918. 



