FUNCTION.] OF EMBRYOLOGY. 233 



earlier stages of development. That part of the embryo in 

 which the condensed tissues occur, and which, from its 

 appearance and frequent tendency to constriction round its 

 base, I at first suspected was the only part of the embryo 

 (the rest being then funiculus), corresponds, I think, in 

 situation with the collet ; it is very evidently not the point of 

 the radicle, for this will subsequently be found so close to 

 the vesicle as to authorise me in assuming that the greater 

 part of the soft cellular tissues becomes the body of the 

 root. 



"None of my observations have tended to confirm his 

 (Schleiden's) idea of the inflection of the embryo-sac before 

 the pollen tube ; and it appears to me sufficiently obvious, 

 that if such were the case, the cylindrical bag constituting 

 the ' embryo in its first stage of development/ would consist 

 of three membranes or layers : viz., the first or outer, of the 

 ordinary and uninflected membrane of the sac ; the second, 

 of its inflected portion ; the third, of that of the pollen tube 

 itself." 



M. Schleiden assumes the applicability of his conclusion, 

 drawn from direct observation in several plants, to all others 

 in which direct observation is more difficult, on three distinct 

 grounds, the first of which, regarding the diameter of the 

 tube outside the sac and just within it, is, I cannot but think, 

 of very minor importance, neither does it present itself in 

 Santalum ; the second, which would confine certain peculiar 

 contents to the pollen tube, appears to me contradicted by 

 Santalum and Loranthus ; and the third, which positively 

 refers plurality of embryos to a plurality of pollen tubes, is 

 contradicted in a most marked manner by Loranthus. 



In the Ray Reports we have the following translation of 

 Link's remarks upon the observations made by M. Decaisne 

 upon the Miseltoe ; a very anomalous plant : 



" On examining the ovary in its earliest state, it presents 

 a uniform mass, with two small interruptions of the cellular 

 tissue ; the cells, however, soon unite again, in order to form 

 a clear cellular tissue in the centre, surrounded by a green 

 circle. No ovule is perceived in the ovary for a long time, 

 not as far as the commencement of June, when the ovary has 



