184 Varietäten, Descendcnz, Hybriden. 



Compton, R. H., Notes on Epilobium Hybrids. (Journ. of Bot. 

 p. 158—163, 1911.) 



A description of the offspring obtained by the author as a result 

 of crosses made between Epilobium hirsutum $ X &■• adnatum, f. 

 stenophylla J and between E. adnatum $ X E- montanum <$. 



The hybrids from the former cross differed in some respects 

 from the plant described by Haussknecht and considered by him to 

 be a hybrid between E. adnatum X hirsutum. The hybrid lacks the 

 long runners of hirsutum; the flowers resemble those of adnatum; 

 the Stigma is clavate and slightly notched. The hybrid from the 

 second cross has a shortly 4-lobed Stigma, so that the results of 

 crossing § Synstigma and § Schizogstima are not necessarily identi- 

 cal as regards the character of the Stigma of the hybrid. 



In both cases the hybrids failed to produce fertile seed. 



The author has some well-founded criticisms regarding the iden- 

 tification of wild plants as natural hybrids, merely on the grounds 

 of their intermediate characters and in the absence of experimental 

 evidence. 



A list is given of the artificial hybrids of Epilobium which have 

 been recorded in literature. R. P. Gregory. 





Davis, B. M. , Cytological Studies on Oenothera. III. A 

 comparison of the Reduction Division of Oenothera La- 

 marckiana and O. gigas. (Ann. Bot. XXV. p. 941—974. pl. 71—73. 

 1911.) 



The spireme thread developed at the conclusion of synapsis is 

 much shortened and thickened, and no clear evidence has been 

 noted that it ever becomes doubled by a lengthwise fission to give 

 a "strepsinema" stage. A segmentation of the spireme gives rise to 

 the füll set of sporophytic (somatic) chromosomes arranged end to 

 end. These numbers, fourteen in Lamarckiana and twenty-eight in 

 gigas, are the diploid numbers for these species respectively. There 

 is no general pairing of the chromosomes in the stage of diakinesis. 

 The pollen mother-cells and their nuclei and also the pollen-grains 

 of gigas are much larger than those of Lamarckiana, this suppor- 

 ting the view that in related types the size of the cells and nuclei 

 are proportionate to the number of chromosomes. 0. igigas is a pro- 

 gressive mutant, its peculiarities being clearly associated with the 

 changes in the germ plasma incident upon the doubling of its chro- 

 some number. Agnes Arber (Cambridge, England). 



Fräser, H. C. I. and J. Snell. The Vegetative Divisions 

 in Vicia Faba. (Ann. Bot. XXV. p. 845—855. pl. 62—63. 1911.) 



There are 14 chromosomes in the sporophyte and 7 in the game- 

 tophyte of Vicia Faba. In the course of the nuclear division, a lon- 

 gitudinal fission becomes visible in the daughter chromosomes be- 

 tween the time when they reach the poles of the spindle, and the 

 actual "resting stage". The line of Separation of the daughter chro- 

 mosomes on the spindle is therefore marked out in the preceding 

 telophase, persists throughout the intervening stages. The chromo- 

 somes are frequently constricted into Segments, and it seems pro- 

 bable that the way in which the segments are grouped to form 

 chromosomes may vary. An explanation here suggests itself of the 



