210 Anatomie. — Biologie. 



ded by the study of wounded regions in the oak, and by the struo 

 ture of miocene oaks. 



The author considers the origin of storage tissue about the 

 entering leaf-trace has proved a natural starting-point for the for- 

 mation of these Compound rays. This special storage tissue has 

 gradually extended both above and below the trace, and outward 

 with each annual layer of growth, producing an increasingh 7 larger 

 food-reserve System, until finally, in the higher types, homogeneous 

 masses of ray tissue have been produced. 



The Compound ray exercises a retarding influence on the growth 

 in its vicinity and thus often has a marked effect on the develop- 

 ment of the stem. 



The hypothesis put forward by Sachs concerning the origin 

 of the central cylinder of woody plants is discussed, and the con- 

 clusion is arrived at that it must be reversed, in order to agree 

 with the comparative anatomy of living and fossil plants. This con- 

 clusion is in agreement with the views put forward by Eames 

 (Ann. of Bot. Jan. 1911.) The paper concludes with a revision of the 

 terms used in connection with ray structures. 



E. de Fraine (London). 



Hill, T. G. and E. de Fraine. On the Seedling Structure 

 ofGymnosperms. IV. (Ann. Bot. p. 319—333. 2 Plates. 3 Text- 

 figures. 1910.) 

 The paper deals with the seedling structure of the Gnetales and 

 describes in detail the anatomy and transition phenomena of Ephe- 

 dra distachya, E. fragilis, E. campylopoda, E. altissima, Welwitschia 

 mirabilis, Gnetum Gnemon, G. scandens and G. moluccense, all of 

 which have dicotj^ledonous and epigeal seedlings with a short coty- 

 ledonary tube. The seed-leaf bundles, which are endarch and colla- 

 teral, vary in number, there being two in each cotyledon in Ephe- 

 dra, four arranged in two pairs at the base of each cotyledon in 

 Welwitschia, and four or five in a simillar position in Gnetum. 



The hypocotyl shews stem structure throughout the greater 

 part of its length, the transition to root arrangement takes place 

 immediately below the foot. This latter organ is rod-like in Gnetum 

 and is supplied with vascular tissue, it is spade-like and without a 

 bündle S3^stem in Welwitschia, and is absent in Ephedra. It functions 

 as an organ of absorption, and is of no phylogenetic significance. 

 The transition phenomena are essentially the same through-out the 

 group, each pole of the diarch root being formed from two cotyle- 

 donary bundles, which rotate towards each other and outwards, so 

 as to bring the protoxylems into the exarch position; the metaxylem 

 groups gradually come into continuity and the Strands of phloem 

 more into the intercotyledonary plane and there fuse. There is a 

 resemblance between the transition phenomena of the Gnetales and 

 that of the Podocarpeae and Araucariae. Short tracheids, resembling 

 the transfusion tracheids of other Gymnosperms, occur in the region 

 of the insertion of the plumular bundles on to the cot3'ledonary 

 Strands, and serve as a bridge between the corresponding bundles 

 of the seed-leaves. E. de Fraine (London). 



Liebman, W., Die Schutzeinrichtungen der Samen und 

 Früchte gegen unbefugten Vogelfrass. (Jen. Ztschr. Naturw, 

 XLVI. p. 445—510. auch Dissertation. 64 pp. 1910.) 



Verf. teilt die Vögel in 2 grosse Abteilungen: 1. Weichfres- 



