Anatomie. — Biologie. 147 



47 gibt von dem Aussehen des Stärkekörners in polarisiertem Licht 

 keine richtige Vorstellung u. s. w. Die Namen der zitierten Autoren 

 erscheinen allzu oft in falscher Orthographie. Küster. 



Winge, 0., The pollination and fertilization processes in 

 Humulus hipuliis L. and H. Japonicus Sieb, et Zucc. (Johs. 

 Schmidt: Investigations on hops [Humidiis liipulus L.j III.) 

 (Comptes-rendus des travaux du Laboratoire de Carlsberg, llnie 

 Vol., Ire Livraison, p. 1—44. 2 PL, 22 F., 1914.J 



The result of the investigations may be summed up as follows. 



Zinger's description of the formation of the embryo-sack and 

 the growing together of the integuments in Humulus is correct, 

 but the author is wrong in his Statement, that the ovule lacks a 

 micropyle, the presence of which has already been determined by 

 Lermer and Holzner. 



The microspores are developed and ripen in basipetal order in 

 correspondence with the dehiscence of the pollen sacks by means 

 of apical pores 



It is not easy to get the pollen of H. liipulus to grow on an 

 artificial substratum, but the pollen grains of H. Japonicus grow 

 willingly on a gelatine Solution. 



The pollen grains of //. lupulus retained their power of growth 

 for 3 days on being kept in a dry room of the laboratory. 



The tapetum in Humulus offers a good example of multinuclear 

 cells and vegetative caryogam3^ the original divalent nuclei divi- 

 ding repeatedly, after which the products of division constantly 

 fuse together. This gives rise to plurivalent, synkaryonlike nuclear 

 complexes. 



Rosenberg's and Bonnet's theory, that the tapetum origina- 

 tes phylogenetically from the archespore and consists of sterile 

 archespore cells, cannot be accepted , and for this reason it cannot 

 be admitted either, that atavistic tendencies give the explanation 

 of the nuticlear condition of the tapetal cells. It is suggested, that 

 the peculiar nuclear condition of the tapetum has a physiological 

 explanation and the same applies to the endosperm's wealth of 

 chromosomes. Both tissues are to a very great extent connected with 

 the nutrition, which must be taken to be reflected in the abundance 

 of chromatin. 



The growth of the pollen tube in Humulus does not suggest 

 true aporogamy, as Zinger maintains. Zinger's description of the 

 deep Penetration of the pollen tube into the integuments is some- 

 what exaggerated, especiallj^ in \.he C3.se oi H. Japonicus. The more 

 or less advanced age of the ovule at the moment of pollination 

 affects the route by which the pollen tube penetrates to thenucellus, 

 the ovule in younger flowers being less curved than in older, yet 

 nevertheless ripe for fertilization. In younger flowers the pollen 

 tube must pass a longer way through the integuments. In certain 

 cases — in older flowers of H. Japonicus — the pollen tube passes 

 directly b}'^ the conducting tissue to the nucelles without touching 

 the integuments. 



The number of chromosomes in the somatic cells is 20 and 16 

 in H. lupulus and H. Japonicus respectively ; in the x-generation 

 respectively 10 and 8. In the tetrad formation two longitudinal 

 divisions of the chromosomes are observed, but no transversa 

 division. 



