578 Morphologie etc. — Varietäten, Descendenz, Hybriden. 



Wager, H., The Life Historj^ and Cytology of Polypliagus 

 Englenae. (Ann. of Bot. XXVII. p. 173—202. Apr. 1913.) 



Polyphagiis Euglenae, one of the Chytridiaceae, is parasitic on 

 Euglena viridis to which it is attached b}" delicate pseudopodia. 

 Reproduction takes place by zoospores which are formed sexually 

 or asexuall}'. In the sexual method of reproduction the z3'gotes are 

 formed by the fusion of uninucleate gametes. Two gametes come 

 in contact with each other by means of a copulating Pseudopodium 

 which grows out from the smaller or male cell. The zj^gote is formed 

 by the swelling of the apex of the copulating tube at the point 

 where it comes in contact with the female cell. The contents of the 

 male and female cells, each with a nucleus, pass into the z3'gote. 

 The male nucleus grows tili the two sexual nuclei are equal in size, 

 after which large quantities of chromatin are extruded from the 

 two nuclei and this chromatin fuses to form a granulär mass. After a 

 resting period of five months the Zygote germinates giving rise to 

 a thin walled sporangium. The chromidial mass and the two nuclei 

 pass into the sporangium and the latter fuse. 



The chromidial mass is distributed throughout the sporangium 

 and after a series of mitotic divisions of the Single nucleus numerous 

 zoospores are produced each of which is seen to have a nucleus 

 and a small chromidial mass. 



"That nuclei have both somatic and generative functions is well 

 known and Schaudinn suggested that these two functions reside 

 in distinct parts of the nucleus''. "In Polyphagiis .... the nucleus 

 has this dual structure to the extent thaf the chromidia represent 

 the vegetative or somatic element and the small nuclei .... the 

 generative element". "The double fusion which takes place in the 

 life cycle of Polyphagiis is clearly bound up with this dual function 

 of the nucleus, the chromidial fusion in the zj'^gote promoting vege- 

 tative growth whilst the nuclear fusion in the sporangium precedes 

 the formation of the spores". 



It is suggested that the double fusion in Polyphagiis "may 

 afford some clue to the explanation of the delaj^ed nuclear fusions 

 and double nuclear fusions observed in the higher Fungi". In con- 

 sidering the nuclear phenomena of the Asconiycetes the author sa3"s 

 "may not the nuclear fusion in the sexual apparatus and the nuclear 

 fusion in the ascus be simply regarded as the vegetative and gene- 

 rative phases of a Single sexual act which have become separated 

 owing to the Interpolation of a series of vegetative divisions between 

 the formation ofthe ascogonium and the production of the ascospores". 



E. J. Welsford. 



Fletchep, J. J., On a case of natural Hybridism in the 

 Genus Grevillea. (N. O. Proteaceae.) (Linn. Soc. N. S. Wales Proc. 

 July 30th. 1913. p. III— IV.) 



Grevillea laiirifolia Sieb., and G. acanthifolia A. Cunn., are two 

 common and characteristic members of the flora of the higher 

 portion of the Blue Mountain area. Certain other rare forms are 

 sometimes associated with one or both of them, some of which 

 have been described under the name of G. Gaudichaiidii R.Br. The 

 object of this paper is to justify the contention, that the rare.plants 

 to which the name G. Gaudichaiidii R.Br., has been applied, or is 

 applicable, form one group only of a series of transitional forms 

 between G. laiirifolia and G. acanthifolia, of which another, equally 



