402 Allgemeines. — Morphologie etc. 



nährungs- und Befruchtungs-)Verhältnissen berichtet werden. Die 

 Aehren der Getreidearten und die Samenkeimung sind gut zu 

 kontrollieren. Das Gleiche lässt sich von den Pilzwucherungen, 

 Gewebeneubildungen sagen. Auch die Kunst kann vieles aus 

 gelungenen Röntgenaufnahmen entnehmen. Die Farbenpracht 

 vermisst man allerdings an den Röntgenogrammen, da die Farben- 

 photographie sich mit der Anwendung des Röntgenverfahrens 

 leider nicht vereinigen lässt. Matouschek (Wien). 



Davie, R. C, On the Leaf-trace in some Pinnate Leaves. 

 (Transactions Roy. Soc. Edinburgh. LH. 1. N°. 1. p. 1—36. With 

 1 PI. and 17 Figures in the Text. February 1917.) 



This is an anatomical study of the form of the foliar bündle 

 and the emission of the pinna-trace in the pinnate leaves of Ferns, 

 Cycads, Monocotyledons and Dicotyledons. 



Among the Ferns the bundles of which are described are 10 

 species of Polypodium, viz. P. brasiliense Poir., P. loriceum L., P. 

 decurrens Ruddi, P. catharinae Langsd. et Fisch., P. fraxinifolium 

 Jacq., P. serrulatum (Sw.) Mett., P. cultratum Willd., P. lepidopteris 

 (Langsd. et Fisch.) Kze., P. plumula H. B. Willd. and P. polypodioi- 

 des (L.) Hitchcock. All these were collected by the author in 

 Brazil. Dr. Davie also describes and gives diagrammatic figures 

 of the vascular bundles of a series of fronds of Polypodium vulgare 

 L. coming from very different situations in Scotland. He also 

 describes the foliar bundles in Aspidium martinicense Spring., A. 

 trifoliatum (L.) Sw., Leptochilus guianensis (Aublet) C. Chr., Poly- 

 stichum adiantiforme (Forst) J. Sm. and Dryopteris grandis (Pr.) C. 

 Chr., all species collected in South Africa. 



In the case of P. fraxinifolium and P. brasiliense specimens 

 growing under very different natural conditions were examined. 

 Some came from „restingas", narrow Strips of Sandy ground lying 

 between the mountains and the sea; others were found in the under- 

 growth of the rainforests of Monte Corvado. The plants growing 

 on the restingas had larger and more numerous vascular bundles 

 in their petioles than the specimens gathered in regions with a 

 moister atmosphere. Moreover, although P. catharinae, which grew 

 in exposed positions on a restinga, was almost indistinguishable 

 from P. loriceum, which grew in a forest, its petiole had larger 

 and more numerous vascular Strands. Throughout the genus Poly- 

 podium the emission of the pinna-traces is constantly marginal. But 

 the length of the leaf and the size of the pinnae greatly affect the 

 form of the foliar bündle; with increasing length of the leaf and 

 size of the pinnae the abaxial portion of the bündle develops 

 greatly. In P. serrulatum, which has the shortest leaf and smallest 

 pinnae, the vascular bündle is a mere compact rod, the edge of 

 which becomes slightly extended before the nipping off of the pinna- 

 trace; in P. cultratum, P. plumula and P. lepidopteris, which have 

 larger leaves, the bündle has an abaxial development of tracheides; 

 in the species with still larger leaves this comes to constitute a 

 separate System of Strands. These abaxial Strands serve as a re- 

 inforcement system to the adaxial Strands just after or before the 

 emission of the pinna-trace. In P. decurrens, in which we find the 

 largest individual pinnae, the abaxial series gives off a small Strand 

 which passes directly into the pinna, so that we get a „combination" 



