Morphologie etc. — Varietäten etc. 261 



Price, S. R., Seme studies on the Structure ofthe Plant 

 Cell by the method ofDarkground Illumination. (Ann. 

 Bot. XXVIII. p. 601-632. 2 pl. 1914.) 



The method of dark-ground illumination, which has hitherto 

 been only sparingly used in botanical work, has been applied by 

 the author to a detailed study of the plant cell under various con- 

 ditions The method is very restricted in application, on account of 

 the difficulty of selecting suitable material for examination. A des- 

 cription of the method used is given and also of the structure of 

 various types of material studied. 



The protoplasm is regarded as a colloid complex which seems 

 to exist both in the hydrosol and hydrogel State. To a certain extent 

 these States appear to be spontaneousl}'^ reversible. The process of 

 germination of certain fungus spores followed by the method showed 

 the gradual conversion of the gel contents of the spore into a hy- 

 drosol. The structure of the nucleus and chloroplasts, the effects of 

 plasmolysis and the action of fixing and coagulating agents were 

 also studied. Agnes Arber (Cambridge). 



Thompson, J. Mc L., Studies in Floral Zygomorphy. I. 



The Initiation of Staminal Zygomorphy. (Trans. Roy. 



Soc. Edinb. IL. 3. p. 691—704. 2 pl. 1913.) 

 The author studied the flower of Greyia Sutherlandii {Melian- 

 fhacceae) in which the 10 stamens are all found to be of different 

 lengths. He shows that zygomorphy is a progressive character in 

 this case: it first appears in the perianth and later in the androe- 

 cium and gynoecium. The androecium is first actinomorphic. but 

 becomes antero-posteriorlj^ zygomorphic. Lateral zygomorphy then 

 follows. Actinomorphy is almost or entirely restored in the perianth, 

 while lateral zygomorphy continues for a time and dominates the 

 androecium, but the latter becomes morphologically actino- 

 morphic, when the anthers have dehisced. The antero-posterior 

 zygomorphy in the young bud is caused by ditferences in the 

 cambial activity in the filaments, and the later lateral zygomorph}'' 

 is mainly due to differences in the rate of cell-elongation. 



In Staphylea pinnata (an actinomorphic flower) the great increase 

 in stamen-length immediately previous to anther dehiscence is pri- 

 marily due to the elongation of the filament cells (extension). 



A.gnes Arber ^Cambridge). 



Doncaster, L., Chromosomes, Heredity and Sex: A Review 

 of the Present State of the Evidence with regard to 

 the Material Basis of Hereditarj'- Transmission and 

 S e x-D etermination. (Quart. Journ. Mic. Sei. Vol. LIX. p. 487—521 . 

 4 Text-Figs. 1913.) 



This paper is mainly zoological. In the first section a summary 

 is given of the main lines of argum.ent leading to the conclusion 

 that "Mendelian characters are determined by chromosomes". In 

 the second section the chief classes of facts are reviewed which 

 suggest a relation between chromosomes and sex-determination. 

 It is concluded that the arguments for a relation between chromo- 

 somes and sex are much stronger than those connecting chromo- 

 somes with Mendelian factors. In the third section the facts of 

 sex-limited inheritance are discussed. Lastly, certain difficulties are 



