88 BOTANICAL GAZETTE [july 





Doubling of embryo sac. — Compton 32 reports an interesting situation in 

 a Lychnis hybrid, in which an ovule contained two embryo sacs, each pene- 

 trated by a pollen tube, and each containing a two-celled embryo. He calls 

 this "a curious example of duplicity. " The closing statement is worth remem- 

 bering: "The fact that two pollen tubes should enter and fertilize an ovule 

 which had developed two embryo sacs can hardly be a mere coincidence; 

 rather it would seem to indicate a quantitative relation between embryo sac 

 and pollen tube in the matter of chemotaxis, two embryo sacs excreting suf- 

 ficient of the chemotropic substance to attract two pollen tubes." — J. M. C. 



Seedling structure of Centrospermae. — Hill and DeFraine^ have 

 recorded the results of an extended survey of the transition phenomena of 

 the seedlings of Centrospermae. The "theoretical considerations" are to be 

 presented later, but in the present paper there are indications of what they may 

 be. The families presented, through abundant representatives, are Portu- 

 lacaceae, Caryophyllaceae, Amarantaceae, Chenopodiaceae, Phytolaccaceae, 

 Aizoaceae, and Nyctaginaceae. The authors state that "no very striking 

 results" were obtained, and that the chief interest is connected with the features 

 of the last-named family. — J. M. C. 



Fall of leaves. — Based upon a mass of data collected largely from 

 the literature, Combes** shows that the conception of Sachs regarding the 

 migration of substances at the time of leaf fall is no longer tenable. The 

 substances that do not disappear from the leaves, as well as those that accumu- 

 late in them before their fall in the autumn, are not to be considered a priori 

 as substances non-utilizable or toxic for the plant containing them. The 

 fallen leaves contain an important percentage of substances that would have 

 been utilizable by the plant. — Chas. O. Appleman. 



Morphology of Viola. — Miss Bliss** has studied five species of Viola 

 with reference to the structures connected with the embryo sac. The hypo- 

 dermal archesporial cell, the tapetal cell, the linear tetrad, and all the ante- 

 fertilization structures of the sac are what may be regarded as normal for 

 angiosperms. Double fertilization was observed in V. cucullata. "There 

 is no suggestion of a suspensor," and the embryo, surrounded by a solid mass 

 of endosperm, is bright green.— J. M. C. 



* Compton, R. H., Note on a case of doubling of embryo sac, pollen tube, and 

 embryo. Ann. Botany 26: 243, 244. 1912. 



33 Hill, T. G., and DeFraine, Ethel. On the seedling structure of certain 



rm 



Ann. Botany 26:175-199. figs. 15. 1912. 



w Combes, Raout, Les opinions actuelles sur les phenomenes physiologiques qui 

 accompagnent la chute des feuilles. Rev. Gen. Bot. 23:129-264. 1911. 



35 Bliss, Mary C, A contribution to the life history of Viola. Ann. Botany 



26:155-163. pls.iy-ig. 1912. 

 \ 



