534 Descendenz und Hybriden. 



Benson, M., The Origin of Flowering Plant s. (The New 

 Phytologist. Vol. III. No. 2. p. 49—51. 1904.) 



A Short note discussing recent work on the Gnetaceae, 

 especially Giietum, in reference to the ancestry of the Angio- 

 sperms. It is pointed out that the embryo-sac of Gnetum is 

 such that the characteristic embryo-sac of the Angiosperms may 

 have been evolved from it. The ovule of Gnetum is surrounded 

 by three envelopes, the inner of which together with the nu- 

 cellus is regarded as constituting a synangium; the middle one 

 probably represents the outer integument of the Angiospermic 

 seed, and the outer, as has frequently been pointed out, the 

 carpei. In the so-called „male flower" parallel parts are also 

 present, Further if the internodes of the so-called inflorescence 

 be suppressed, and the whole spike reduced to a conical torus- 

 with suppression of the bracts, we should then have the struc- 

 ture of the central part of such an Angiospermic flower as 

 Liriodendroii. 



Moreover as some „spikes" are androgynous, with the car- 

 pels occupying the uppermost nodes, we may even obtain the 

 ambi-sporangiate flower by the same process of reduction. In 

 Welwifschia the telescoping of the internodes has been accom- 

 plished, and we have the outlines of the Angiosperm.ic flower 

 for the first time laid down. 



In its anatomy also Gnetum exhibits characters approxima- 

 ting to those of Angiosperms. In Drimys, and other genera 

 allied to Liriodendron, homoxyious secondary wood is recorded, 

 so that each phylum seems to approximate to the other on 

 anatomical grounds. Arber (Cambridge). 



Petersen, 0. G., Formentlige Bastarder mellemSkovfyr 

 og Bjorgfyr (Hybrides pretendus de Pinus silvestris 

 et F. montana). (Tidsskrift for Skovvoesen. Bd. XV. Kjöben- 

 havn 1903. p. 171 — 184.) 



Description de quelques pins cultives, intermediaires entre 

 Pinus silvestris et P. montana. Un exemplaire du Jutland 

 p. ex. ressemble ä P. silvestris par les caracteres suivants: 

 cones tournes vers le bas, aiguilles pointues, tandis qu'il se 

 rapproche du P. montana par ses cones presque sessiles, peu de 

 canaux secreteurs dans les feuilles. La structure de l'epiderme 

 est presque la meme que chez le P. silvestris, se rapprochant 

 pourtant de celle du P. montana. Dans l'ensemble, cet arbre 

 est semblable ä P. silvestris, tandis que, des arbres nes de ses 

 graines, quelques-uns sont semblables ä P. silvestris, d'autres 

 ä P. montana. II n'est pas prouve qu'on ait vraiment affaire ä 

 des hybrides. O. Paulsen. 



Ravn, f. Kolpin, Forplantning og Arvelighed. (Pro- 

 pagation et hdredite.) (Videnskabeligt Folkebibliotek. 

 Kjöbenhavn 1904. p. 1 — 119. Avec 24 figures dans le texte.) 



