Band 141. Nr. 19. XL. Jahrgang. IL Bd. Nr. 19. 



Botanisches Centralblatt. 



Referierendes Organ 



der 



Association Internationale des Botanistes 

 für das Gesamtgebiet der Botanik. 



Herausgegeben unter der Leitung 

 des Präsidenten: des Vice- Präsidenten : des Secretärs: 



Dr. D. H. Scott. Prof. Dr. Wm. Trelease. Dr. J. P. Lotsy. 



und der Redactions-Commissions- Mitglieder : 



Prof. Dr. Wm. Trelease, Dr. C. Bonaventura, A. D. Cotton, 



Prof. Dr. C. Wehmer und Mag. C. Christensen. 



von zahlreichen Specialredacteuren in den verschiedenen Ländern. 



Dr. J. P. Lotsy, Chefredacteur. 



I Abonnement für das halbe Jahr 25 Mark 



durch alle Buchhandlungen und Postanstalten. 



1919. 



Alle für die Redaction bestimmten Sendungen sind zu richten an: 

 Redaction des Botanischen Centralblattes, Haarlem (Holland), Spaarnei7. 



Raunkiaer, C Om Lövspringstiden hos Afkommet af 

 Böge med forskellig Lövspringstid. [On leaftime in 

 the descendants from beeches with different leaf- 

 time s]. (Bot. Tidsskr. XXXVI. 3. p. 196—203. Köbenhavn 1918. 

 With an english abstract.) 



In the first place, the author has satisfied himself, that early 

 beeches in the forest wefe early not only in a Single year but also 

 in the following years. 



Next, seeds were collected of trees with different leaftimes, and 

 the seeds were sown separately. The descendants showed a striking 

 correspondence to the mothers with regard to leaftime. Thus, early 

 or late leaftime is genotypically determined. 



If the genotypic base of „early leaftime" is a Single factor it 

 may be either dominant or recessive. Of the four theoretically pos- 

 sible cases to follow, two are excluded by the results of the expe- 

 riments made, and it is likely, that the mother plant is heterozygous 

 with regard to the factor for leaftime, and that this factor is domi- 

 nant. But it may be most reasonable to assume, that leaftime is 

 conditioned by a complicated combination of genotypic factors. 



„The most important point is that the experiments show that, 

 within Fagus silvatica, there are sub-species, isoreagents, that are 

 different with regard to leaftime." Ove Paulsen. 



Weatherwax, P., Gametogenesis and fecondation in Zea 

 Mays as a basis ofXeniaandheredityinendosperm. 

 (Bull. Torr. Bot. Club. XLVI. p. 73—90. pl. 6, 7. March 1919.) 



Of the four megaspores the chalazal one develops. An embryo 



Botan. Centralblatt. Band 141. 1919. 19 



