500 Morphologie, Teratologie, Befruchtung, Cytologie. 



The nucleus of the definitive archesporial cell, or embryosac 

 mothercell, goes into synapsis before its first division. 



Evanescent cell-walls occur foUowing the first and second nu- 

 clear divisions in the embryosac in all six of the species ot which 

 the material was most nearly complete. 



The mature sac contains sixteen nuclei, one of which tunctions 

 as the eo-g nucleus, one as that of the Single synergid, from six to 

 nine others fuse to form the endosperm nucleus, and the remamder 

 are individually cut off by cell-walls about the periphery of the sac 

 and afterwards degenerate. 



The endosperm is cellular from the Start. 



The embryo is undifferentiated externally except for a shght 

 flattening on the micropylar side. 



In Piper tubenulatum we have a typical eight-nacleate embryo- 

 sac, developed directly from the definitive archesporial cell, no 

 degenerating megaspores being formed. . 



That the first four nuclei in the embryosac of Peperomia are 

 homologous with megaspore nuclei, seems extremely probable from 

 the foUowing facts: 1. they arise from a cell which with very little 

 doubt may be considered a megaspore mother cell; 2. they are 

 arranged tetrahedrally; 3. the tetrad is complete m number; 4 the 

 lareer than usual number of nuclei in the mature sac is m har- 

 monv with this view; 5. the reduction of chromosomes occurs in the 

 divisions which give rise to these four nuclei; 6. a restmg stage 

 follows the formation of these four nuclei; and 7. evanescent cell 

 walls frequently foUow the first and second divisions in the embryo- 

 sac but not the third. 



In view of the foUowing considerations: 1. that the primary 

 archesporial cell of Peperomia is single - a condition probab y 

 derived- 2 that the first four nuclei of the embryosac are probably 

 homoloious with megaspores - certainly not a primitive feature; 

 3 that the peculiar origin of the endosperm nucleus here probabl> 

 represents a derived condition; 4. that an endosperm which is 

 cellular from the Start cannot be regarded as primitive; and 5 that 

 none of the close relatives of Peperomia furnishes any mdication. 

 from the development of the embryosac, that the genus is primi- 

 tive the writer is inclined to believe that the pecuUanties in origin 

 and' development of the embryosac of Peperomia have been secon- 

 darily acquired. Jongmans. 



Gadeceau. E., Observations sur 1' heterostylie dans le 

 genre Oxalis. (Bull. Soc. bot. de France. LXI. p. 133-137. 1914.) 

 L'auteur a constate deux fcrrmes d'Oxalis florihunda, une forme 

 raesostylique et une forme longistylique. Chaque lorme cultivee 

 r/parement, ne donne pas des graines. Les deux formes plantees 

 cö?e ä cöte, produissent des capsules fertiles. On obtient le meme 

 resultat en fecondant artificiellement la forme longistylique avec le 

 pollen de la forme mesostylique. L'auteur de l'espece. Lehmann, 

 n'en a decrit que la forme longistyhque. Jongmans. 



Hamet, R., L'anisomerie fl^rale dans la famille des 

 Crassulacees. (Revue gener. de Bot. LX. p, 84-92. 1913.) 

 L'isomerie de la fleur a ete consideree, pendant longtemps, 

 comme un caractere toujours present dans la famiUe des Crassula- 



