428 Meyen's Report for 1839 on Physiological Botany. 



dently means the suspensor of the embryo. All that I have 

 said in the 3rd volume of my ( Vegetable Physiology' against 

 Dr. Schleiden' s theory of fertilization, applies in an equal de- 

 gree to that of M. W., and I therefore refer my readers to 

 the former Report, &c. &c. 



Since then MM. Mirbel and Spach* have also opposed the 

 theory of Schleiden ; they have made observations on the de- 

 velopment of the embryo in Zea Mays, and have confirmed 

 the results thus obtained in many other grasses, as in Eu- 

 chlcena mexicana, Coioc Lacryma, Tripsacum hermaphroditum, 

 Sorghum vulgare, &c. &c. 



MM. Mirbel and Spach observed the complete development 

 of the ovulum and the ovarium, and have given full descrip- 

 tions accompanied by figures ; they consider the formation 

 of the above-mentioned cavity as the first appearance of the 

 embryo-sac in the end of the nucleus, and call the gum con- 

 tained therein " amorphous cambium." Finally, the trans- 

 parency of this gum disappears, and in the cavity of the nu- 

 cleus there is seen a proportionately large tube, egg-shaped 

 and transparent ; this was called " utricule primordiale f at 

 the upper end (chalaza end) it is furnished with a slender elon- 

 gation, on which small cells are fastened in the form of a com- 

 pound raceme ; at the lower end it terminates in a thread- 

 shaped tubular appendage, which extends into the endosto- 

 mium, and may be compared to the suspensor in other plants. 

 It is shown that this primordial or primitive tube is not pro- 

 duced by a depression of the embryo-sac, for the Graminece 

 have no embryo-sac at all. 



Soon after the appearance of the primitive tube they re- 

 marked in it the formation of a " cambium globulo-cellulaire," 

 which consisted of globules, in each of which there is a central 

 cavity. This cambium forms finally a mass of cellular tissue, 

 Avhich fills the cavity of the tube and the supporter, which lat- 

 ter becomes larger and longer. This primitive tube being 

 filled with cellular tissue is the young embryo, which, as the 

 authors say, no one will doubt ; the upper end thickens, 

 spreads itself out like a blunt-headed lance and becomes the 

 hypoblast of Richard, while the lower end exhibits for some 

 time the lax thread or supporter. These gentlemen have con- 

 vinced themselves long since that the formation of the primi- 

 tive tube takes place before the action of the pollen, and that 

 it is quite independent, that it is produced in the nucleus 

 and does not descend into it. Schleiden evidently took this 



* Notes pour servir a l'Histoire de l'Embryogenie Vegetale. — Compt. 

 Rend., Mars, 1839 ; Annates des Sc. Nat. 1839, I. 



