lil Linncean Society. 



"It is curious," Mr. Griffith observes, "that this prolongation 

 [of the embryo- sac] has only been observed in association with a 

 particular form of the free central placenta. So far as I know," he 

 adds, " it is the only instance of an embryo -sac prolonged posteriorly, 

 it may be said, from two points of its surface." And further : " In 

 all the really analogous instances in which the albumen is exterior 

 to the ovulum, it is always exterior, that part of the embryo -sac in 

 which it is developed being protruded long before any albuminous 

 tissue has been developed*." 



In conclusion, Mr. Griffith refers to the observations of Mr. Brown 

 on the ovula of Avicennia in the ' Prodromus Florse Novse HoUandise,* 

 and in Dr. Wallich's ' Plantse Asiaticse Rariores,' and states that 

 the most important difference between this last account and that 

 which he has given is, that he finds the embryo only to be erect. 

 *' The embryo, in its earlier stages of development, undergoes a degree 

 of change of direction, but only sufficient to enable it to pass up out- 

 side the ovulum in the same direction it would have maintained had 

 it been ordinarily developed." 



The paper was illustrated by a series of coloured drawings. 



December 3.— E. Forster, Esq., V.P., in the Chair. 



Read, some " Remarks on Vegetable Physiology." By Mr. James 

 Main, A.L.S. 



Mr. Main's object in the present paper appears to be the reproduc- 

 tion before the Society of the leading ideas on vegetable growth con- 

 tained in his * Illustrations of Vegetable Physiology,' published in 

 1833, and to state his objections to some received theories on that 

 important subject. He denies the descent of the sap, and asks, " Who 

 has met with sapless branches in winter, or surcharged roots at the 

 same season ? " He states that " the spring movement of the sap 



♦ In a Memoir by M. Planchon, published at Molitpellier, 1844, " Sur les 

 d6veloppements et les caracteres des vrais et des faux arilles, suivi de con- 

 siderations sur les ovules de quelques V^roniques et de V Avicennia," it is 

 shown that in two species of Veronica ( V. kedercsfolia and V. Cymhalaria) 

 (and consequently in plants with the ordinary form of placenta) the nucleary 

 ovula are furnished with embryo-sacs, acquiring during the progress of their 

 growth two tubular prolongations, one from near each extremity, the upper 

 of which passes into the placenta, and there becomes digitately divided. In 

 these plants also the albuminigerous portion of the embryo-sac becomes, 

 during the progress of its development, external to the nucleus. In other 

 species of the same genus {Ver. agrestis and V. arvensis) the ovula are 

 equally reduced to a nucleary form ; but the embryo-sac is much less de- 

 veloped at its extremities, and a tegument derived from the nucleus con- 

 tinues to enclose it up to the complete maturity of the seed. Comparing 

 these observations on Veronica with the description given in 1818 by M. A. 

 de St. Hilaire of the development of the ovulum oi Avicennia, M. Planchon 

 comes to the conclusion, that " II devient impossible de ne pas considerer, 

 avec Brown, comme I'ovule lui-meme le corps oblong pris [par M. A. de 

 St. Hilaire] pour un cordon ombilical, et de ne pas voir dans le tubercule 

 arrondi qui sort de lafente du corps oblong, un sac embryonnaire analogue a 

 celui de la Veronique, et destine, comme ce dernier, a accomplir, hors du 

 nucelle, toutes ses evolutions." — Secr. 



