Origin and Development of the Vegetable Embryo. 59 



consider the pollen-grain, not as the ovule of the plant, but as its 

 fertilizing organ; that Schleiden's theory of vegetable impregnation 

 is false." 



He considers these observations as a complete proof of this 

 proposition, since he worked with such care and perseverance 

 that he ventures to consider them incontestable. They refer to a 

 single species alone, and this of a family possessing many pecu- 

 liarities, but he believes that every one will agree with him in 

 idea that the process of fecundation is essentially the same in all 

 Phanerogamous plants, that is, in reference to the question whe- 

 ther the pollen-grain or the ovule produces the embryo — what- 

 ever modifications of the minor points may occur in different 

 families. At the end of his memoir the author offers some spe- 

 culations which have arisen out of the foregoing observations. 

 He asks whether the three germinal vesicles which are formed in 

 the upper end of the embryo-sac may not be identical in their 

 nature with R. Brown's corpuscula in the Coniferce : the chief 

 difference between them appears to be, that in the Orchidacete 

 the suspensor (the filamentous elongation) consists of a single 

 row of cells and takes a backward course, breaking through the 

 nucleus and growing out into the seed, the embryo remaining in its 

 place ; while in the Coniferce the suspensor is composed of several 

 rows of cells and breaks through the embryonal vesicle below, so 

 that the growing embryo at its lower extremity attains its fuller 

 development outside the embryonal vesicle*. 



K. Miiller f has followed the development of ovules in a num- 

 ber of plants ; he gives a minute account of his observations on 

 Orchis Morio, Monotropa Hypopitys, Begonia cucullata and Ela- 

 tine alsinoides. He fully confirms the statements of Amici and 

 Mohl with regard to O. Morio, the only point of difference being 

 that he could never see the end of the pollen-tube filled with 

 green matter as above described. Otherwise he traced the pollen- 

 tube through the foramina of the coats and saw it lying on the 

 side of the summit of the embryo-sac. His researches in 0. la- 

 tifolia, paludosa, maculata, militaris, Platanthera bifolia and 

 Ophrys ovata yielded similar results. In all these the embryo 

 was produced from the lower cell of the series produced from the 

 germinal vesicle. In Monotropa the pollen-tube is applied di- 

 rectly to the apex of the embryo-sac, and the embryo is here 



* It appears to me that this parallel is not well-grounded : have not tlie 

 corpuscula of the Coniferce rather the import of embryo-sacs, like those 

 of Viscum, than of germinal vesicles? This is the opinion of Schleiden. — 

 Rep. 



f Beitrage zur Entwickelungsgeschichte des Pflanzen-embryo, von Karl 

 Miiller.— Botanische Zeitung, Oct. 15, 22 and 29, 1847. 



