70 BOTANICAL GAZETTE [july 



nuclei between 70 and 82. There is no cyclic alteration in the number of chro- 

 mosomes, and no migration or fusion of nuclei of prothallial cells. The embryo 

 arises from the unfertilized egg. 



In Lastrea pseudo-mas polydactyla Wills, the authors still maintain their claim, 

 made in a preliminary paper, that there is a migration and fusion of prothallial 

 nuclei, thus initiating the sporophytic phase. There is a normal reduction of 

 chromosomes. 



In Lastrea psetido-mas polydactyla Dadds there is a reduction of chromosomes 

 and the sporophyte is initiated by a migration and fusion of prothallial nuclei. 

 The embryo, however, comes from a projection which may be regarded as an 

 arrested archegonium. 



In Lastrea pseudo-mas cristata apospora Druery there is no reduction of chro- 

 mosomes and no migration of prothallial nuclei. The number of chromosomes 

 shows a remarkable variation, there being 60 in nuclei of prothallial cells, about 

 78 in nuclei of the embryo, and about 90 in nuclei of antherozoids. 



These various forms may be arranged in two categories, one in w^hich spores 

 are produced in connection with the usual reduction of chromosomes; and the 

 other in which there is no spore formation or reduction of chromosomes, the 

 embryo appearing as an outgrowth from the sporophyte. The wide variation in 

 the number of chromosomes is not thought to be due to inaccuracy in counting, 

 but to a real difference. The authors believe that the fluctuation might seem to 

 negative any value being attached to the number of chromosomes. 



After a lengthy discussion a general conclusion is drawn which is quite at 

 variance with current notions, namely that there is no necessary correlation 

 between the periodic reduction in the number of chromosomes and alternation of 

 generations. Fertilization and reduction, however, are recognized as holding a 

 definite causal relation to each other, but without assuming any necessary connec- 

 tion between either of them and any other features in the life-history. — Charles 

 J. Chamberlain. 



Apogamy in Marsilia. — While investigating apogamy 



ported 

 Ls bota 



apogamy 



Since 



in the Kew and Berlin herbaria. Some of the sporocarps 

 collected more than thirty years ago, germinated readily. 



megaspores 



microspores 



abundantly as when 



crospores are present. Sections show that embrj^os often develop from eggs 



without 



sporophyte number, 



tips and other vegetative structures. Megaspores are formed which have 2^ 

 chromosomes in their nuclei, the reduction of chromosomes ha\ing failed to take 



" Strasburger, E., Apogamy bei Marsilia. Flora 97:123-191. pis. 3-8. 19^7- 



