Allgemeines. — Anatomie. 451 



Eriksson' s hypothesis, which refers the epidemic out- 

 breaks of rust to the sudden transformation into the mycelial 

 form of a supposed infeetive substance, previously latent and 

 invisible in the eytoplasm of the host, is shown to be untenable 

 becanse the corpuscnles speciaux of this author are pro- 

 ved to be the cut-off haustoria of the fungus. 



Eriksson supposes that the corpuscnles (haustoria) 

 are formed by the hithertho latent germs in the host cells, 

 growing up in the cells into vesicles, which then pierce the 

 cell walls and give rise to hyphae in the intercellular Spaces. 



The present paper shows that Eriksson has entirely 

 reversed the true order of events. The haustoria have been 

 formed by the hyphae, and figures are given showing every 

 stage in their development. The first haustorium may be formed 

 bythe infecting tube immediately after its penetration through 

 the stoma, and figures are given showing the remains of the 

 germ-tube outside a stoma, the swelling of its tip over the 

 stoma into an appressorium, the passage through the stomatal 

 eavity, and its development into a vesicular swelling whence 

 the true infection tube arises, which latter may at once put 

 forth a haustorium. In some cases all these latter phenomena 

 are visible in one and the same preparation." a. D Cotton. 



BOUYGUES, Sur l'existence et l'extension de la moelle 

 dans le petiole des Phanerogames. (Comptes lendus 

 des seances de l'Academie des sciences de Paris. T. CXXXVI. 

 23 mars 1903.) 



L'auteur a precedemment signale sous l'epiderme superieur 

 des petioles ä Systeme libero-ligneux ferme une assise dont le 

 recloisonnement est precoce et abondant. A ses depens se 

 differencient, d'un part, une extension du Systeme libero-ligneux 

 et d'autre part, le tissu d'aspect medullaire intercale aux 

 faisceaux. Cette assise est-elle d'origine medullaire ou d'origine 

 corticale? 



M. Col se basant sur la position de l'endoderme a cru 

 pouvoir affirmer qu'elle est medullaire, mais on sait qu'il peut 

 se produire deux endodermes successifs, le premier aux depens 

 du meristeme cortical, le second aux depens du meristeme 

 vasculaire; la position de l'endoderme caracterise ne peut donc 

 rien prouver. L'etude du developpement des tissus sera seul 

 capable de fournir la Solution de la question. Lignier(Caen). 



Chauveaud, G., Developpement des tubes precurseurs 

 et des premiers tubes cribles dans X Ephedra altissima. 

 (Bulletin Museum d'Histoire naturelle. 1903. p. 94.) 



Dans la radicule de \" Ephedra altissima il existe, comme 

 chez les Coniferes, des tubes precurseurs entre le pericycle et 

 les premiers tubes cribles. D'autre part, les tubes cribles initiaux 



29* 



