Band 116. Nr. 6. XXXII. Jahrgang. I. Bd. Nr. 6. 



Botanisclies Centralblatt. 



Referirendes Organ 



der 



Association Internationale des Botanistes 

 für das Gesamtgebiet der Botanik. 



Herausgegeben unter der Leitung 

 des Präsidenten: des Vice- Präsidenten: des Secretärs: 



Prof. Dr. E. Warming. Prof. Dr. F. W. Oliver. Dr. J. P. Lotsy. 



und der Redactions-Coniniissions- Mitglieder : 



Prof. Dr. Wm. Trelease, Dr. R. Pampanini, Prof. Dr. F. W. Oliver, 

 Prof. Dr. C. Wehmer und Dr. C. H, Ostenfeld. 



von zahlreichen Specialredacteuren in den verschiedenen Ländern. 



Dr. J. P. Lotsy, Chefredacteur. 



Nr. 6. 



Abonnement für das halbe Jahr 14 Mark 

 durch alle Buchhandlungen und Postanstalten. 



1911. 



Alle für die Redaction bestimmten Sendungen sind zu richten an: 

 Redaction des Botanischen Centralblattes, Leiden (Holland), Bilder- 

 dijkstraat 15. 



Bailey, I. W., Anatomical characters in the evolution of 

 Pinus. (Amer. Nat. XLIV. p. 284—293. 1910.) 



Anatomical features are found to have been of comparative 

 constancy and hence of value in tracing the evolution of the genus. 

 Cretaceous pines as well as Prepinus Jeffrey are found to have exclu- 

 sively paciform pits on the lateral walls of the rays, with an absence 

 of marginal ray tracheids. From this condition the subsequent evo- 

 lutionary changes give among modern pines the development of 

 ray-tracheids, the disappearance of thick-w^alled ray cells, the origin 

 of large, Compound raj'' pits bj^ the fusion of small pits with circular 

 borders, and the loss of tangential pitting in the autumnal tracheids. 

 The hard and soft pines with very large lateral ray pits are con- 

 sidered the most advanced of living pines. Gates. 



Boodle, L. A. and W. E. Hiley. On the Vascular Structure 



of some Species of Gleichenia. (Ann. of Bot. XXIII. n^. 91. Julv 



1909.) 



The authors give an account of the anatomy of Gleichenia 



[Mertensiä) pectinnta; this species is solenostelic Avith outer and 



inner mesocycle and sclerenchyma; the internal structure of the 



rhizome is markedly dorsiventral. Among the interesting points 



brought out are the existence in this species of two kinds of bran- 



ching — raonopodial and dichotonious (in which the branches appear 



to be truly equal) and the presence of a little entirely disconnected 



Botan. Cent.ralbl.iU. Band 116. 1911. 10 



