346 M. Tulasne's Researches in Vegetable Embryogeny. 



free for a very short space. Several pollen-filameuts often intro- 

 duce themselves in this manner into each ovuliferous cell, but it 

 cannot be so frequently proved that the micropyle of the ovule 

 gives entrance to more than one of them. Their extremity 

 which comes in contact with the euibryo-sac is obtuse and 

 scarcely inflated ; it applies itself to the surface of the embryo- 

 sac by twisting in various manners, or lodges itself in a shallow 

 depression which it sometimes causes. The point of insertion of 

 the suspensor of the embryo usually corresponds with the point 

 of contact of the fecundating tube. 



The suspensor in the Caryophyllacese is far from being of the 

 same tenuity as in the Labiatae ; its diameter on the contrary is 

 very considerable, and it is divided into several very unequal 

 cells. It is attached by a broad base to the apex of the em- 

 bryo-sac, and sometimes, as in Alsine media, L., for instance, 

 is elongated in a remarkable manner at this point, without how- 

 ever quitting the sac, which appears rather to become intimately 

 united with it. The pollen-filament of the Pinks is remarkably 

 voluminous, and contracts such an adherence to the embryo- 

 sac, that it easily resists the dragging inseparable from the dis- 

 section of the ovule ; its extremity is often bifid, and then sits 

 as it were astride upon the sac above the embryoferous disc. 

 M. Schleiden's theory is here shown to be in fault in a most 

 evident manner. 



The unusual development of the suspensor towards the micro- 

 pyle presented by Stellaria media, Sm., occurs also, but in a very 

 exaggerated form, in the genus Calendula. In these plants, the 

 suspensoi', which is at first entirely enclosed in the embryo- 

 sac, soon becomes formed of two distinct parts : one tubular, 

 always enclosed and continuous with the nascent embryo; the 

 other excessively inflated into an oval or elongated vesicle, the 

 greater part of which is protruded from the sac. ]M. Schacht 

 does not appear wilhng to admit that the suspensor may thus 

 grow simultaneously in opposite directions at its two extremities. 

 Would he therefore regard that of Calendula as a modified and 

 metamorphosed pollen-filament ? There is nothing, certainly, 

 more improbable than such a metamorphosis. 



The same author is also in the wrong in calHng in the Viola 

 tricolor, L., in support of his theory. Whenever we have been 

 able in this plant to see the pollen-filament supporting its kneed 

 extremity upon the embryonal sac, it has been manifest to us 

 that it remained entirely out of the sac, that is to say, that be- 

 tween it and the more or less enlarged embryonal vesicle, the 

 embryoferous membrane was always extended, in the form of an 

 uninjured diaphragm. 



The same circumstances may also be easily observed in Helian- 



