1885.] NEW-YORK MICROSCOPICAL SOCIETY. 11 



bryonic vesicles) usually appear within the embryonic sac, below 

 the tip of the pollen-tube. These vesicles elongate ; the upper 

 and thinner end adhering to the membrane of the sac. While 

 one of the two shrinks and disappears, the other develops, and 

 fills more or less completely with its free end the cavity of the 

 embryonic sac. * * * * ^U physiologists concur in the 

 above." 



Le Maout and Decaisne describe also the fertilization of San- 

 talum, and give illustrations of it.^* "The fertilization of the 

 ovule in Santalaceae, presents a quite exceptional phenomenon, 

 which deserves to be mentioned. The ovary is unilocular, and 

 the free central placenta bears several suspended ovules ; each 

 is a naked nucleus. At the period of fertilization the nucleus 

 bursts at the lower part, the embryonic sac emerges by this open- 

 ing and ascends along the whole length of the outer surface of 

 the nucleus, to meet the pollen-tube a little below the top of the 

 nucleus. The latter soon withers, and the embryonic sac, which 

 alone grows, forms the integument of the seed." 



H. Marshall Ward, in an elaborate paper " On the Embryo- 

 sac and Development of Gymnadenia conopsea,"^^ says of its im- 

 pregnation, " The pollen-tube, after a sinuous course from the 

 placenta, has made a sharp bend ere plunging into the micro- 

 pyle, and has then spread its broad apex over the ' Gehiil- 

 finnen,'^" apparently penetrating between the sac and the integu- 

 ment ; but the difficulty of following so delicate an outline as it 

 presents is no ordinary one. * * * * If no pollen-tube 

 enters the micropyle, the whole ovule turns brown, shrivels, and 

 the contents of the sac become ill-defined, and decay." 



In Griffith and Henfrey's Micrographic Dictionary, last edition, 

 there is a figure of the embryo-sac and supporting cells of Orchis 

 Morio, after the contact of the pollen-tube. The two are shown 

 in contact (pi. 47, fig. 5). 



In Gymnosperms, after the pollen-tubes have extended for a 

 short distance into the ovule, their growth temporarily ceases, or 

 progresses very slowly ; they enter on a period of rest. " This 

 continues in the annual-seeded Coniferse a few weeks, in the 

 biennial-seeded about a year. For example, the pollen-tubes 

 reach the corpuscula of Taxus baccata at the end of May of the 



'*Loc. cit., p. 157 ; flgs. 751, 752, 753. 



'^Quart. Journ. Micros. Sci., Vol. XX. (New Series), p. 1, pis I., 11., lU. 



'^Germinal vesicles. Literally, female consorts. 



