Morphologie und Teratologie. 407 



removed in June threw out side branches with water-type 

 leaves when other plants under the same external conditions 

 were forming the land type. At one stage in its developement 

 Proserpinaca is positively heliotropic and at another it is dia- 

 heiiotropic; the production of the water-type oi leaf is intimately 

 connected with the latter stage and the land-type with the 

 former. 



He concludes that the cause of the division of the leaf does 

 not depend on external conditions. The plant has an adult and 

 a juvenile form; under good vegetative conditions there is a 

 tendency to produce the former with entire leaf, blossom, and 

 fruit; under poor vegetative conditions the latter with divided 

 leavcb. A reversion to the primitive form may be caused by 

 unfavourably influencing the vegetative conditions. 



M. Wilson (Glasgow». 



Robertson, A., Studies in the Morphology of Torreya 

 californlca Torrey. II. The Sexual Organs and 

 Fertilisation. (New Phytologist. Vol. HI. Nos. 9 and 10. 

 1904. p. 205—216. With plates VII— IX.) 



The germination of the megaspore takes place about the 

 end of June, the endosperm developing throughout July. The 

 outermost layer of the endosperm in the lower part of the sac 

 becomes distinguishable from the rest by its conspicuous nu- 

 clei and rieh starch content; it may be of an epithelial nature 

 and secrete a ferment. The archegonia, generally three in 

 number, appear at the beginning of August; the neck consists 

 of one tier of five to six cells. The nucleus of the central cell 

 divides but no ventral cell is formed, the nucleus being short 

 lived. 



The generative nuclei do not organise cells and are con- 

 tained in a single sheath; they are of equal size but only one 

 is functional. Fertilisation occurs early in September, between 

 three and four months after pollination. The male nucleus be- 

 fore fusion presses in the membrane of the egg nucleus and 

 the cytoplasmic sheath of the fusion nucleus is contributed to by 

 the male cell. Wall formation begins in the pro-embryo when 

 four free nuclei are present and finally the pro-embryo con- 

 sists of a tier of cells, surmounted by the rosette cells and 

 terminated at the chalazal end by a cell Cluster. The number 

 of chromosomes in the female gametophyte appears to be eight. 



M. Wilson (Glasgow). 



WORSDELL, W. C, Fasciation: its Meaning and Origin. 

 (New Phytologist. Vol. IV. Nos. 2 and 3. Feb. and Mar. 

 1905.) 



The subject is introduced by the consideration of two set 

 of phenomena, viz: 1. negative d^doublement or cohe- 

 sion, i. e. the fusion of organs or tissues which were once 



