Biologie. — Morphologie, Befruchtung, etc. 645 



couleur importe peu ä l'Insecte; ce qu'il recherche, c'est du nectar 

 et du pollen; le sens qui le guide vers ces objets de sa convoitise 

 semble etre principalement l'adorat. Henri Micheels. 



Beer, R., The supernumer ary PoUen-Grains of Fuchsia. 

 (Annais of Botany. Vol. XXI. p. 305—307. 1907.) 



Instances are quoted from the literature in which the number 

 of pollen-grains produced from a Single mother-cell is either greater 

 or less than four. Two explanations have been oftered of cases in 

 which more than four are present. Wille (who examined Fuchsia) 

 considers that one or more of the tetrad of pollen-grains divides 

 again, but Juel (who examined Hemerocallis) holds that the high 

 number of grains produced is due to the occurrence of irregulari- 

 ties in the distribution of the chromosomes during the anaphase of 

 the first division of the mother-cell. The author's observations on 

 the division pollen mother-cell in Fuchsia do not confirm Wille's 

 description, but shew that the process takes place in a way com- 

 parable to that reported by Juel for Hemerocallis. 



A. Robertson. 



Beppidge, E. M., The Origin of Triple Fusion. A Suggestion. 



(New Phytol. VI. p. 279. 1907.) 



The author brings forward a new theory as to the origin of the 

 Angiospermous endosperm, suggested by her observations on Ephedra. 

 In this genus a small group of nuclei lying at the apexof the embryo- 

 sac gives rise to the archegonial region. Some of the nuclei divide 

 once and thus give rise to the primary neck and central cells of 

 archegonia. The others undergo a series of divisions and form jacket 

 cells. The &gg and jacket nuclei are very much alike, and in E. 

 distachya certain of the latter after fusion with another nucleus 

 (usuall}'' but not always belonging to another jacket cell) even form 

 suspensors and rudimentary embryos. The author points out that 

 here we have cell formation resulting from the fusion of nuclei, (one of 

 which at least is allied to the egg nucleus), taking place under the 

 Stimulus due to the entry of the pollen-tube. This strongly recalls 

 the manner of endosperm formation in the Angiosperms, and the 

 author's view is that the upper polar nucleus of Angiosperms repre- 

 sents the jacket-cells of Ephedra. The endosperm is hence regarded 

 as being of a pro-embryonal nature, but derived from cells which 

 had already, earlier in their phylogenetic history, assumed a nutri- 

 tive function. Thus the two views very generally held with regard 

 to the endosperm of Angiosperms, first that, being a nutritive 

 tissue, it must be prothallial, and second that, being a product of 

 fertilization , it must be an embryo, would be hereb}^ reconciled. 

 Moreover the Suggestion made by Miss Sargant, that the endosperm 

 is to a certain degree a monstrous embryo, owing to some want 

 of balance in the Constitution of its nuclei due to its threefold pa- 

 rentage, is in no way precluded. A. Robertson. 



Campbell, D.H., The Embryo-Sac of Pandanus. Preliminary 

 Note. (Annais of Botany XXII. 86. p. 330. 1908.) 



The embrj^o-sac of Pandanus differs decidedly from the usual 

 Angiospermous type, and to some extent recalls that of Peperoniia. 



