Band 141. Nr. 2. XL. Jahrgang. II. Bd. Nr. 2. 



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. G. Bonaventura, A. D. Cotton, 



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



von zahlreichen Specialredacteuren in den verschiedenen Ländern. 



Dr. J. P. Lotsy, Chefredacteur. 





No. 27. 



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), Spaarne 17. 



Frye, T. C, The age of Pterigophora californica. (Publ. Puget 

 Sound Biol. Stat. II. p. 65—70. pl. 17. 1918.) ' 



Three different lines of Observation agree in indicating annual 

 growth rings in the stipe, the fronds reaching an age of nearly a 

 quarter of a Century. Trelease. 



Holden, M. S. and D. Bexon. Observations on the Anato- 

 my of Teratological Seedlings. I. On the Anatomy of 

 some Polycotyledonous Seedlings of Cheiranthus Cheiri. 

 (Ann. Bot. XXXII. p. 513—530. 17 textfigs. 1918.) 



The authors obtained a strain of Wallflower which threw a 

 considerable percentage of abnormal seedlings and thus offered a 

 favourable opportunity for an anatomical studj 7- of teratological 

 polycotyly. The total number of polycotylous seedlings examined 

 was 54, which are classified as follows: Hemitrocotyls, 9; Tricotyls, 

 32; Hemitetracotyls 1; Tetracotyls, 12. The authors' study of these 

 seedlings is believed to indicate at least two, and possibly three, 

 methods of cotyledonary increase: 1) by cotyledonar}' fission, 2) b5' 

 dichotomy of the growing point of the Cotyledon, 3) much more 

 doubtfully, by the downward displacement of one or more epicoty- 

 ledonary leaves. 



The paper concludes with a füll discussion of the literature of 

 pol3'cotyly. It is shown that previous work on schizocotyty is ca- 

 pable of Interpretation on the basis suggested by the authors of 

 the Wallflower, and that it affords illustrations of the three types of 

 cotyledonary increase which they have been led to recognize. 



Agnes Arber (Cambridge). 



Botan. Centralblatt. Band 141. 19i9. 2 



