Meyen's Report for ] 839 on Physiological Botany. 429 



tube for the end of the pollen-tube which had penetrated into 

 the nucleus. 



The raceme of small cells which crowns the primordial 

 tube at the upper end has been overlooked by Schleiden, and 

 MM. Mirbel and Spach state them to be abortive primordial 

 tubes. 



The results of the observations are too evident to require 

 any very full explanation. According to them, the fertiliza- 

 tion of Zea Mays takes place neither according to the new 

 nor the old theory : the observations are quite unfavourable to 

 the new view ; for the tube which produces, or is changed into 

 the embryo, does not come into the nucleus from without, but 

 is formed in it and at a distance from the pollen. How the fer- 

 tilization takes place, MM. Mirbel and Spach show they are 

 quite ignorant. The observations of these gentlemen were so 

 very different from my own former ones, that I was obliged to 

 convince myself of their correctness*. I examined the female 

 flowers of the Zea Mays, and not only found the above disco- 

 veries perfectly correct, but was fortunate enough to be able 

 to add some new observations. I saw that the extremity of 

 the primitive tube w T as always closed and never in communi- 

 cation with the pollen-tube ; the primitive tube becomes 

 embryo, and out of the ovoid cells at the lower (chalaza) end 

 is produced the scutellum, which grows more or less over 

 the whole embryo in the form of a folding leaf; out of the 

 small lower cleft of this scutellum there hangs the radicular 

 end of the embryo, and exhibits the half lifeless string of 

 cells which formed the supporter at the end of the primitive 

 tube. I have often succeeded in extricating the little embryo 

 from the imperfectly formed scutellum. 



Afterwards M. Mirbel t acknowledged that his discovery of 

 the primitive tube, out of which the embryo was formed, was 

 erroneous; he convinced himself that this utriculus is the 

 true embryo-sac in which the embryo and the albuminous 

 body are formed ; and according to this also the error into 

 which I have fallen must be corrected ; it was caused by my 

 trusting more to these observations than to my own, which 

 had been made previously. 



[To be continued.] 



* Meyen, Noch einige Worte uber den Befruchtungsakt und die Polyem- 

 bryonie bei den boheren Pflanzen. 2 Steintafeln. Quarto. Berlin, 1840. 

 p.21. 



f Rectification d'une erreur commise dans les " Notes pour servir a. 

 PHistoire del'Embrvogenie Vegetale." — Annales des Sci. Nat., Avril, 1839. 

 Part. Bot. i. p. 381/ 



