Band 137. Nr. 5. XXXIX. Jahrgang. I. Bd. Nr. 5. 



Botanisches Centralblatt 



Referierendes Organ 



der 



Association Internationale des Botanistes 

 für das Gesamtgebiet der Botanik. 



Herausgegeben unter der Leitung 

 des Präsidenten: des Vice-Präsidenfen: 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. 



No.5. 



Abonnement für das halbe Jahr 15 Mark 

 durch alle Buchhandluno^en und Postanstalten. 



1918. 



Alle für die Redaction bestimmten Sendungen sind zu richten an: 

 Redaction des Botanischen Centralblattes, Haarlem (Holland), Spaarnei?. 



Blackburrt, K. B., On the vascular anatomy of the young 

 epicotj'^l in some Ranalean forms. (Ann. Bot. XXXI. p. 

 151 — 180. 1 pl. 19 text figs. 1917.) 



In this study the Ranunculaceae receive the chief attention, but 

 other families are also included. The method adopted was to cut 

 serial microtome sections from the stem apex to the upper part of 

 the hypocotyl of seedlings bearing from one to five expanded 

 foliage leaves in addition to the cotyledons. 



The most general morphological type is that in which the first 

 few internodes are relatively short and the ph3'llotaxis is two fifths. 

 The cotyledons are epigeal and, where the first internodes are 

 specially short, the first two foliage leaves tend to be opposite and 

 at right angles to the cotyledons. A cotyledonary tube is frequently 

 found. With the exception of the very specialised Nymphaeaceae , 

 the divergence from the type just described is in very limited and 

 definite directions; 



a) In Calycanthus and in some species of Clematis, the early 

 foliage leaves are decussate, and in Anona the phyllotaxis is 

 one-half. 



b) Hypogeal germination is found in certain large-seeded forms. 

 It occurs throughout Lauraceae and Anonaceae and in certain spe- 

 cies of Ranunculaceae. 



There is also a general anatomical type to which most of the 

 seedlings conform. Each foliage leaf contributes three traces to the 

 axial vascular cylinder, which consists of a circle of separate colla- 

 teral bundles, anastomosing as the nodes. Early cambial activity 

 connects the Strands by secondary tissue. The most notable excep- 

 tion to the general arrangement is in Laurus, where the insertion 



Botan. Centralblatt. Band 137. 1913. 5 



