Anatomie. — Morphologie etc. 563 



Single sieve plate on the end wall. The lists adduced show that the 

 Woody Dicotyledons are found in the first of these classes, which 

 is also the type of conifers, while the herbaceous Dicotyledons 

 occur either in the third class or between the second and third 

 class. These facts add to the evidence for the view that the herba- 

 ceous Dicotyledons have been derived from woody plants. 



M. A. Chrysler. 



Holden, R., Ray tracheids in the Coniferales. (Bot. Gaz. 

 LV. p. 56—65. pl. 1-2. Jan. 1913.) 



A careful search shows ray tracheids to be present in various 

 genera of Ciipressiueae and Taxodineae, where they had previously 

 been reported as absent. They generally occur in connection with 

 wounds in these families, while they are normal in mo3t genera of 

 Abietiiieae. They sometimes occur on the margin of a ray, but when 

 scarce are more apt to constitute the whole of a narrow ray. It is 

 pointed out that Pityoxyla from the Middle Cretaceous on show ray 

 tracheids, and from this fact and the evidence derived from trau- 

 matic reactions it is inferred that the Taxodineae and Cupressineae 

 sprang from the Abietineae at some time after the Middle Creta- 

 ceous, also that Podocarpineae , Taxineae and Araucarineae came off 

 from Abietineae at some time before the Middle Cretaceous. 



M. A. Chrysler. 



Salisbury, E. J., The Determining Factors in Petiolar 

 Structure. (New Phyt. XII. 8. p. 281—289. 4 Tab. 1913.) 



In Clematis sp., Bignonia and Clerodendron sp. it is shewn that 

 a definite relation exists between the transpiring surface of the leaf 

 and the xylem development in the petiole; an indication was obtained 

 also that a correspondence exists between the xylem development 

 and the rate of transpiration. Local variations do not appreciably 

 affect the final result provided that they extend only over a short 

 distance. 



Some observations on sun and shade leaves oi Stnchys sylvatica 

 indicate that their different potentialities for transpiration are such 

 as to almost exactly equalise the differences in the humidity of 

 their habitat. 



In Rheum and Ruinex increase in petiolar bundles corresponds 

 with increasfe in leaf area. 



The author concludes that the functions of the leaf have a pro- 

 found influence both upon the amount and arrangement of the xylem. 



E. de Fraine. 



Aulin, F. R., Bildningsafvikelser hos Cytinus alpiniis 

 och Acer platanoides. (Svensk Bot. Tidskr VII. 2 Textfig. 1913.) 



Folgende Bildungsabweichungen werden aus Mittelschweden 

 beschrieben und abgebildet. 



An Cytisus alpinus war der Blütenstand durchwachsen; bei 

 wenigblütigen Trauben trug der apikale Achsenteil zahlreiche, 

 bei reichblütigen wenige Laubblätter. Im folgenden Frühjahr waren 

 diese Sprosse abgestorben. Die durchwachsenen Sprosse wurden 

 nur an den stehen gebliebenen Teilen abgeschnittener Zweige, 

 wo die Reservenahrung sich angehäuft hatte, beobachtet. 



An einem Strauch von Acer platanoides mit abgebrochener 



