12 MEYEN ON VEGETABLE IMPREGNATION 
times misled by those observations to consider the fully de- 
veloped funiculus of the embryo as the remnant of the pollen- 
tube. 
MM. de Mirbel and Spach* have also come forward with a 
very interesting memoir against the new doctrine of M. Schleiden 
on the sexes of plants; they have made their observations on 
the formation of the embryo in the Grasses, and particularly 
in Maize, and have discovered some hitherto unknown and 
very important phenomena, which serve still further to show 
what an exceedingly manifold diversity there may be in the im- 
pregnation and formation of the embryo in plants. They dis- 
covered that in the Maize a separate transparent bag is formed 
within the small cavity in the summit of the nucleus, which is 
transformed into the embryo; this bag or utricle is, accord- 
ing to Brongniart, the germ-vesicle, and was regarded by M. 
Schleiden as the end of the pollen-tube. But MM. de Mirbel 
and Spach found that this bag originates directly from the 
cambium, i.e. from the formative sap of the cavity of the 
nucleus, and indeed even previous to the action of the pollen, 
and called it ?utricule primordiale. How impregnation takes 
place in the Maize and in some other tropical Grasses, they have 
not been able to state; but they have endeavoured to demon- 
strate that the primordial utricle is neither the apex of the pol- 
len-tube, nor can the name of embryo-sac be applied to it. At 
the inferior extremity of this utricle the above-mentioned ob- 
servers found a small group of minute ovate cells, and they are 
inclined to believe that these small cells are nothing more than 
abortive primordial utricles; but they do not mention what fur- 
ther becomes of them. At the period of the formation of the 
embryo in the seeds of Mais the primitive utricle first expands 
in length, and especially the extremity situated toward the mi- 
cropyle expands into a long and slender bag. In the interior of 
the primitive utricle cellular tissue is formed, and from this ori- 
ginates the embryo, whilst its long-extended apex is converted 
into the funiculus, and does not disappear till after the perfect 
development of the scutellum [Schildchen]. Quite unexpected 
as these communications on the formation of the embryo in 
Mais, &c. were to me, and undoubtedly to many other observers, 
yet from my recent researches relative to this subject on the 
* Notes pour servir a |’ Histoire de l’Embryogénie Végétale :—Compt. Rend. 
18 Mars, 1839. 
