Morphologie, Teratologie, Befruchtung, Cytologie. 323 



Champy fixe moins bien les cellules de la racine de ricin que la 

 methode de Regaud. Pour obvier ä cet inconvdnient, l'auteur ä 

 essaye de combiner les methodes de Regaud et de Hüll. II a 

 obtenu en fixant une racine de ricin par la methode de Regaud, 

 et en la colorant par la methode de Hüll, de süperbes prepara- 

 tions, mais cette technique ne permet pas de colorer l'amidon qui 

 reste incolore. II faut donc attribuer la coloration de l'amidon par 

 la methode de Champy-Hull ä une modification chimique de cette 

 substance sous l'influence de la fixation d'apres Champy laquelle le 

 rend colorable par le bleu de toluidine. 



M. J. Sirks (Wageningen). 



Michell, M. R>, The embryo sac of Richardia africana Kth. 

 (Botan. Gazette. LXI. p. 325-336. PI. 21-23. 1916.) 



The ovary of Richardia africana is usually trilocular and has 

 axile placentation. Four ovules are borne in each loculus. The 

 ovule is not very decidedly anatropous and has two integuments. 



By the time the embryo sac is mature only a few cells at the 

 apex and base of the nucellus remain. 



The primary sporogenous cell gives rise directty to a row of 4 

 megaspores. The embryo sac is derived from the lowest of these. 

 An 8-nucleate embryo sac develops in the normal way. 



The antipodals usually degenerate early, and when the embryo 

 sac is mature often cannot be distinguished from the nucellus, 

 which also undergoes a certain amount of degeneration. 



The embryo sac persists for a long time in the stage when 

 only 5 nuclei are distinguishable. The egg apparatus is normal and 

 the 2 large polar nuclei lie in a mass of granulär protoplasm at the 

 base of the embryo sac. 



The proembr} r o is spherical, with a minute suspensor. 



In one ovule a 2-celled structure looking like a young embryo 

 was found at the chalazal end of the embryo sac. 



The endosperm develops from the base upward, and is probably 

 accompanied by wall formation. 



A few cells at the base of the endosperm are much larger than 

 the rest. The\ r possess hypertrophied nuclei and granulär proto- 

 plasm. Their function is probably that of passing up food material 

 to the young endosperm and embryo. 



The process of fertilization is rather difficult to demonstrate. 

 Only one case of undoubted fertilization has been observed. Even 

 in its native habitat Richardia does not set seed freely. If pollina- 

 tion has occurred, usually most of the ovaries on an inflorescence 

 have been pollinated. Jongmans. 



Nothnagel, M., Reduction divisions in the pollen mother 

 cells of Allium tricoccum. (Botan. Gazette. LXI. p. 453—467. PI. 

 28—30. 1 Fig. 1916.) 



During late telophase of the last division of the sporogeneous 

 tissue a row of vacuoles appears along the median longitudinal 

 axis of each chromosome, these enlarging until each member is a 

 ladder-like structure. Accompanying this there is an end to end 

 approximation. Such is the condition of the resting nucleus. 



The paired threads entering synapsis and there approximating 

 are the two sides of the ladder, the connecting Strands having bro- 

 ken down. This process does not represent the pairing of two 



