Cytologie und Befruchtung. — Descendenz und Hybriden. 217 



100 //, the entire space becoming filied by the enlarging para- 

 site, which, however, remains In the uniceliular condition. The 

 nucleus of the parasite grows untii it cften reaches a diameter 

 of 35 /i(. After reaching this extreme size-the greatest recorded 

 ior the nucleus of a fungus-the nucleus gradually diminishes 

 in size and, at the time of its first division, is not more than 

 10 f.1 in length. 



Dangeard and Rosen, both of vvhom studied an allied 

 species, vS. Taraxaci, claim that the first nuclear division is 

 amitotic, and both agree that in the succeeding divisions both 

 mitosis and amitosis occur. 



The present paper describes the first nuclear division in 

 great detail and shows clearly that it is mitotic and that in the 

 late anaphases it agrees well v^ith mitoses in other fungi, par- 

 licularly with Albiigo. The prophases are very pecuHar. 

 The nuclear^membrane early becomes gelatinized and, during 

 Ihe shrinkage of the nucleus, becomes reduced in area but not 

 in substance since it grow^s in thickness. The chromatin 

 appears in the form of globules which elongate into rods and 

 iinally form a peculiar spirem. The nucleolus completely 

 disappears before the later prophases are reached. The puz- 

 zling peculiarities of the prophases are probably responsible for 

 the divergent accounts. A subsequent paper will deal with later 

 phases in the life history. Charles J. Chamberlain (Chicago). 



Daniel, Lucien, Sur une greffe en ecusson de liias. 

 (Comptes rendus des seances de l'Academie des sciences de 

 Paris. 13 juillet 1903.) 



1. L'affinite relative ou difference des capacites fonctionnelles 

 entre le sujet et le greffon aux divers moments de la Symbiose 

 joue un role important dans la reussite, la duree et la biologie 

 de toutes les greffes. 



2. Les conditions du milieu exterieur, et particulierement 

 les variations brusques de ce milieu ont une repercussion con- 

 siderable sur le tout, repercussion plus grande que dans la 

 plante normale. 



3. Les accidents (thyllose, pourriture grise, etc. . . .) sont 

 les consequences d'une nutrition defectueuse resultant d'un 

 greffage mal assorti. Dans la greffe en ecusson du lilas, la 

 resistance du sujet et du greffon aux influences du miiieu et aux 

 maladies cryptogamiques est diminuee. Bonnier. 



MOTELAY , Sur u n Robinla Pseiido - acacla pyramidal 

 observe ä Royat. (Actes de la Soc. linneenne de Bor- 

 deaux. Vol. LVIL 1902. p. CLXXI— CLXXn. Avec figure.) 



Cet arbre, fastigle comme le Populns pyramidalis, est tres 

 eleve; les branches et les rameaux sont dresses; ils naissent 

 des la base du tronc et forment une longue et etroite pyramide. 

 Les aiguillons sont tres rares. Paul VuiUemin. 



