660 Morphologie, Teratologie, Befruchtung, Cytologie. 



a Compound leaf rather than to the more specialized petioles of some 

 of the simple-leaved families. M. J. Sirks (Haarlem). 



Cook, O. F., Pomegranate flowersdimorphic. (Journ. Wash. 

 Acad. Sc. II. p. 434—437. 1912.) 



Though it seems quite improbable that such a specialization 

 should not have been described before, the existence of two forms 

 of flowers in the pomegranate is not recognized in the chief works 

 of reference. The two forms of flowers can be distinguished by the 

 shape of the buds long before the time of opening. In perfect flowers 

 the style is long and the stigma is carried out beyond the mass of 

 stamens. This makes it possible for the Stigma to be exposed as 

 soon as the calyx opens, and while the stamens are still completely 

 covered by the infolded petals, an arrangement obviousl)'' favorable 

 to cross-fertilization. In the other type of flowers the ovat^s are 

 poorly developed and have only minute rudimentary ovufe that 

 degenerate and shrivel; the styles are much shorter than in the 

 perfect flowers. 



The staminate form of flowers was much more ^umerous on 

 most of the bushes and some of them had none öf*the perfect 

 flowers, so that no fruit could be set. Thus the pomegranate may 

 be considered as a polygamodioecious plant, to the extent that a 

 large proportion of the flowers no longer produce functional pistils. 

 On the other hand, the perfect flowers show no apparent tendency 

 to lose the staminal function. It is as though a simple dimorphism 

 of Short and long styles had been followed b}' a further reduction 

 of the pistils and ovules of the shortstyled flowers, until the repro- 

 ductive functions were lost. 



The bearing of the dioecious tendency upon the problem of 

 breeding fruiting varieties of pomegranates is obvious. Failure to 

 produce a sufificient number of the fertile flowers would render a 

 variety unproductive, though it might blossom abundantly. On the 

 other hand, the possibility that some varieties require cross-fertiliza- 

 tion, should receive consideration. M. J. Sirks (Haarlem). 



Lundegardh, H., Zur Mechanik der Kernteilung. (Svensk 

 Botanisk Tidskrift. VIII. 2. p. 161-180. Mit Textfig. 1914.) 



Verf. experimentierte mit Victa faha. Gipste er die Wurzeln 

 ein, so fand eine Hemmung der Kernteilungen statt. Letztere ist 

 auf eingestelltes Zellwachstum und Abnahme der Karyotin-Synthese 

 zurückzufuhren. Dagegen fahren die Karyotinlokalisation und die 

 Gestaltsveränderungen der Karyotinelemente (also zwei für die 

 Prophase charakteristische Erscheinungen) fort. Die selten auftre- 

 tenden Spireme sind in den so behandelten Wurzeln sehr dickfädig. 

 Solche Spireme mit sehr kurzen und dicken, ganz freien Chromo- 

 somen treten in Wurzeln auf, die bei 36° C gehalten wurden. Auch 

 hier findet eine Hemmung des Membranwachstums und der Karyo- 

 tinsynthese, sowie der Teilungsers.cheinungen im Plasma statt. Dazu 

 tritt eine Lähmung der Karyotinlokalisation und der gestaltenden 

 Kräfte in Interphase und Prophase ein. — Die prophasische Orien- 

 tierung der Spiremfäden ist z. T. auf innere autonome Sj'^mmetrie- 

 verhältnisse zurückzuführen, die namentlich in den bei hoher Tem- 

 peratur gehaltenen Wurzeln sehr deutlich hervortreten. — Die 



