] tj Stopes and Fujii, The nutritive relations of the sarrounding tiasues etc. 



to be distributed all over the irregularlj bhickened membrane 

 closing the pits of the i i ist order (<•!'. fig. 1 and 2 and diagram 4). 



A similar arrangemenl < » t" the Plasmodesmen «ras seen in alcohol 

 materiaJ of Cycas, Zamia ßoridana and others, although for the 

 latter specics Smith 1 ) recently elaborated a ncw vicw regarding 

 tlir mechanism of nutrition. elaiming large open Communications 

 betweeD the egg and jackel cells. 



Tili' thick wall oi' the egg appears tu be composed of at least 

 pectin substance, cellulose, and amyloid, for we lind that with 

 ruthenium red and other stains for pectin substance it stains deeply, 

 as it also does with congored, chlorzinc iodine and other cellulose 

 stains, while it goes hluish with simple iodine, indicating amyloid. 



For l'imis practically all that we have stated about the egg 

 cell wall in Ginkgo and the Cycads holds good. 



Although Ferguson 2 ) states that no pit groups as described 

 by Goroschankin have been obserred by her, yet Blackman 3 ) 

 noted a "verv distinctly pitted wall" in /'. sylvestris, and in our 

 materials we found no difficulty in detecting the 1 arger sieves; even 

 in hand sections of yoting stages mounted in water and uiistained 

 they were quite easy to ohserve in tangential direction with so low 

 a power as Zeiss B X 4. The surface riev? of the "sieves" and 

 pit groups is quite similar to those in Cycas or Gingko, but the 

 actual thickness of the wall is much less. Pits of the 2 nrl and 3 rd 

 degree have been observed quite clearly, and although we have not 

 yet seen the Plasmodesmen we are convinced that they exist. The 

 chemiGal nature of the thick wall is apparently the same as in 

 the Cycads and <>i/i/: ; i<>. containing at least pectin, cellulose, and 

 amyloid. 



The question arises as to the reason for the great thickness 

 of this wall. We lind on the wdiole that the larger egg cells have 

 the thicker walls; for example in the cycads, where the egg cell 

 reaches a length of 3 or more millimeters, the wall is sometimes 

 0.15 mm thick, while in Ginkgo with egg cells considerably smaller 

 it is less than half that thickness, and in the relatively small eggs 

 of Pimis we und the wall very much thinner though it is still thick 

 in comparison with those of the endosperm cells. In P. Cembra 

 which has an exeeptionally large female prothallium the w r all is 

 thicker than in the others. The thick wall is probably accounted 

 for all through the Gymnosperms by the need of support and 

 protection for the extremely large and delicate egg, which might 

 easily be crushed by the rapidly growing endosperm. Such a 

 thickness would consequently make it difncult even for soluble 

 food stuffs to pass into the egg, so that pits would be necessary. 

 These pits however need by no means be large open Communications. 



1 ) Smith. I. S.. „Nutrition of the egg in Zamia". (Bot. Gaz. Vol. 37. 

 1904. p. 346 to 352.) 



2 ) Ferguson, M. C, loc. cit. see p. 94. 



3 ) Blackman, V. H.. ..Cytol. feat. of fertiliz. and rel. phenom. in 

 Pimis sylvestris". (Phil. Trans. Boy. Soc. Lond. Ser. B. 1898. see p. 399—400.) 



