ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 361 



BOTANY. 



GENERAL, 



Including- the Anatomy and Physiology of Seed Plants. 



Cytology, 

 including- Cell-Contents. 



Cytology of CEnothera in Relation to Mutation.* — R. R. Gates 

 and X. Thomas publish a paper dealing with mutation-series in 

 CEnothera lata and CE. semilata. The twenty-one plants examined Lad 

 15 chromosomes, although the mutants were derived from 14-chromo- 

 some races. Two of the mutants give strong confirmation to previous 

 work, which indicated that the peculiar characters of CE. lata and 

 CE. semilata are constantly associated with the presence of fifteen 

 chromosomes, even when combined with other characters derived by 

 inheritance from 14-chromosome individuals. The extra pair of 

 chromosomes is the result of the distribution of two chromosomes of a 

 pair to the same daughter-nucleus in the reduction-division. The in- 

 constancy of CE. lata and CE. semilata is due to the extra chromosome, 

 and probably the variability of the lata-semilata series has a similar 

 cause. The environmental conditions of the germ-cell and the physio- 

 logical condition of the mother-plant probably determine the ratio of 

 descendants resembling each parent. The extra chromosome associated 

 with the foliage and habit of CE. lata and CE. semilata appears to re- 

 semble the sex-chromosome in such insects as Anasa, and the initial 

 nuclear difference determines the external characters of the series of 

 mutants derived from them. The different types of meiotic irregularity, 

 such as the division of a chromosome on the heterotypic spindle, must be 

 regarded as germinal changes. The facts set out in this and previous 

 papers show that mutations and Mendelian hybrids have their origin in 

 different causes ; the former are due to a germinal change, the latter to 

 a redistribution of the parental characters. 



Physiology. 

 Nutrition and Growth. 



Nitrogen-assimilation by Plant-hairs.f — F. Koressi publishes the 

 concluding paper dealing with a series of experiments performed in order 

 to test the truth of a statement made by certain modern investigators, 

 who assert that newly-formed hairs contain no albumin, and that this 

 substance only appears after the hair has been in contact with the 



* Quart. Journ. Micr. Sci., lix., (1914) pp. 523-71 (3 pis. and 4 figs.). 

 t Rev. Gen. Bot., xxvi. (1914) pp. 106-28 (1 pi. and 2 figs.). 



Aug. 10th, 1914 2 b 



