NOTES ON THE CYTOLOGY AND GENETICS 

 OF THE GENUS FUCHSIA. 



By RUDOLPH BEER, B.Sc, F.L.S. 



(With Plates XXH— XXIV.) 



In contrast to the extensive literature which has grown up rouivl 

 the cytology and genetics of Oenothera very little work has been done 

 upon these subjects in the case of the Fuchsias. In 1850 Wiinmel(l7) 

 called attention to the irregularities in the number and size of the 

 pollen grains produced from the mother-cell of Fuchsia and in 1886 

 Wille (16) made further observations upon the same subject. He counted 

 five to fourteen microspores arising from a single mother-cell. He ex- 

 plained the occurrence of these supernumerary pollen grains by assuming 

 that " In dem Falle, wo bei Fuchsia sp. sieben Zellen entstanden waren, 

 konnte ich nicht darliber im Zweifel sein, das diese daher kam, dass 

 drei der Zellkerne der Tetrade noch sich einmal getheilt hatten, ehe die 

 Cellulosequerwande ausgebildet waren, wahrend der Vierte ungetheilt 

 blieb"(16 p. 61). Where five or six microspores were produced he 

 believed the explanation to be similar. In the case of the higher 

 numbers (e.g. 14) he was unable to follow the cell-divisions, and was 

 uncertain whether the additional pollen grains are due to secondary 

 divisions of one pollen mother-cell alone or whether they are to be 

 derived from two or more primitive mother-cells which have not become 

 separated from one another in the usual manner. 



In 1907 the present writer (1) published a short note upon "The 

 Supernumerary Pollen Grains of Fuchsia and their mode of develop- 

 ment." It was found that the abnormal numbers of pollen grains which 

 develop from the mother-cells is due to the irregular distribution of the 

 chromosomes during the first meiotic division and that no evidence 

 could be found to support Wille's explanation of the phenomenon. 



In 1912 Bonnet (3) published an account of the tapetal cells of 

 certain Angiosperms and included those of Fuchsia among the number. 



Beyond this I can find no literature dealing with the cytology of 

 Fuchsias. 



