Geology and Natural History. 437 



neighbors. It becomes transformed directly into the embryonal 

 sac. From the point of view of physiology, this ovule behaves 

 nearly like ordinary ones, but examined from the point of view 

 of morphology, it is wholly different from them, since it never 

 has any true integument. It is absolutely naked. 



In a subsequent paper, the author considers the fact of poly- 

 embryony in this plant. This phenomenon has recently excited 

 considerable interest from the discovery of its occurrence in cer- 

 tain Leguminous plants (Gutgnard, Ann. Sc. nat. 6 ser., t. XII, 

 p. 35), in Iris Sibirica (Dodbl, 1891, Zurich), and in Lilium 

 Martagon (Overton, same date). The author is satisfied that 

 the multiple impregnation in the case observed by him, was due 

 to the division of the pollinic nucleus after its passage into the 

 embryonal sac. He regards this as indicating that the pollen- 

 grain of Vincetoxicum is comparable to a single antheridium 

 producing the equivalents of antherozoids, here two or more 

 generative nuclei. The author calls attention to the relations 

 which this subject bears to the accepted notion as to the part 

 played by the synergides. He points out also the greater sym- 

 metry of development of the embryos when there is only one 

 present in the embryonal sac, and suggests that the suppression 

 of polyembryony is on the direct line to the more perfect devel- 

 opment of the species. g. l. g. 



8. Researches regarding the effect of leaf-removal in the case 

 of grape-vines. A. Muntz (C. R. 1892, Feb. 22.) — The author 

 has sought to ascertain whether the practice of removing the 

 leaves of the grape-vine just before the ripening of the grapes, is 

 warranted by the results. His observations were made at Verg- 

 nes and Beaulieu, (Gironde), a district where this practice has 

 been in vogue from time immemorial, and where it is regarded 

 as indispensable to the proper ripening of the fruit. In general, 

 his experiments show that defoliation is not followed by favor- 

 able results when the season is dry (like that of last autumn). 

 It may be remembered that experiments by others have given 

 conflicting results. In view of this M. Muntz inclines to hold his 

 judgment in suspense as regards wet seasons, at least. 



Among his incidental results are some which are truly surpris- 

 ing as to the elevation of temperature of the fruits exposed to the 

 direct rays of the sun. But this elevation is not associated with 

 a commensurate increase in the amount of sugar. In some 

 instances there is no increase; there is on the other hand, a fall- 

 ing off in the amount of acidity. Pasteur has noted the latter 

 fact with regard to wine placed in direct sunlight. g. l. g. 



9. The Italian Botanical Society invites the botanists of every 

 nationality to a general assembly in Genoa in order to communi- 

 cate and to discuss the latest discoveries and new ideas and to 

 increase good feeling amongst scientific men. 



This Botanical International Congress will be held in Genoa 

 from the 4th to the 11th of September this year 1892. 



Am. Jour. Sci.— Third Series, Vol. XLIII, No 257.— Mat, 1892. 

 29 



