194 Cytologie und Befruchtung. — Descendenz und Hybriden, 



MiYAKE, K., On the Centrosomes of Hepaticae. (The 

 Botanical Magazine, Tokyo. Vol. XIX. 1905. p. 98—101.) 



IKENO, S., Are the Centrosomes in the antheridial 

 Cells of Marchantia polymorpha imaginary? (The Bo- 

 tanical Magazine, Tokyo. Vol. XIX. 1905. p. 111 — 113.) 



In the first of the above cited papers Miyake describes 

 his observations regarding successive nuclear divisions in the 

 antheridial cells of Marchantia polymorpha, Fegatella conlca, 

 Pellia eplphylla, Makinoa crispata and an Aneiira. The 

 nucleolus is present except in the first of these Hepaticae 

 and as in Fegatella it is comparatively very large and as the 

 nuclear reticulum is very poor in chromatin, he thinks it 

 probable that the nucleolus contributes to the formation of 

 the chromosomes. In all Hepaticae examined by him, 

 he has observed two asters at opposite poles of the divi- 

 ding nucleus, but could never find centrosomes at all, either 

 in the resting stage or in any other; only in the last antheridial 

 division he was able to find two groups of granules near the 

 spindle- poles, which could represent blepharoplasts. From 

 these investigations he disclaims all positive results of his pre- 

 decessors, not only in the antheridial cells, but also in vegeta- 

 tive as well as in spore-mother-cells, and comes to the conclusion 

 (which seems to the reviewer rather hasty) that there is no 

 true centrosome in the Hepaticae at all and that the 

 centrosomes hitherto reported in this plant-group are nothing 

 but centres of cytoplasmic radiations. 



The second paper above cited was written against the 

 Statement of Miyake about Marchantia polymorpha. As this 

 is directly contrary to the observations of the reviewer de- 

 scribed in 1903 (Beih. z. Bot. Centralbl. XV. p. 65), he made 

 a special reexamination of his slides and could easily refind all 

 stages of centrosomes figured in this last paper. He showed 

 also some of his sections to one of his colleagues, who convin- 

 ced himself of the real existence of these bodies. The author 

 therefore concludes that the centrosomes in the antheridial cells 

 of Marchantia are real and constant structures, not at all ima- 

 ginary, as Miyake thinks them to be, and that his negative 

 results are due either to his overlooking these minute bodies 

 or to poor material or to imperfect manipulation. Ikeno. 



MOQUETTE, J. P., Voorloopig verslag over het vind'en 

 van rijstkorrels op ketan, en proeven daarover 

 genomen. (Teysmannia. 1905. No. 10. p- 632.) 



Verf. fand unter den Aehren verschiedener Ketanvarietäten 

 (Klebreis, Oryza gliitlnosa Lour.) einzelne, auf welchen sich eine 

 oder mehrere Reiskörner {Oryza satlva L.) zeigten. Später fand 

 er auch Aehren mit ^4 bis ^/a Ketankörnern und '''j bis ^/a Reis- 

 körnern. 



