124 



M. Schleiden regards this explanation as a supposition totally 

 unfounded, and thinks that he is able to establish as a general 

 law that a bud is never formed upon a leaf. This law however 

 is easily seen, by direct observation of nature, not to exist ; the 

 very supposition is the weakest point of Dr. Schleiden's ex- 

 cellent memoir, and has led him to many forced explanations. 

 I believe that I am able to prove that, if we base the morpho- 

 logical signification of the ovarium on unprejudiced obser- 

 vation, and do not explain the observations according to pre- 

 conceived views, we must admit a four-fold mode of origin of 

 the ovules; viz. they originate most frequently at the margins of 

 the carpel leaves, next at the sides of the midrib of the carpel 

 leaves, more rarely upon their entire inner surface, and lastly 

 also from the axis, where they occur either at the end of the 

 axile formation, or at the side of the frequently much shortened 

 axis. 



I will here draw attention to some of the splendid monstro- 

 sities figured and described by M. Turpin in the work pre- 

 viously noticed*: the explanation it is true frequently stands 

 quite in contradiction to the figured observations. Fig. 19 is 

 the drawing of a monstrous fruit of Aquilegia vulgaris, the five 

 carpel leaves are almost completely rolled up and their lateral 

 walls covered with ovules and leaves. Figs. 28 and 29 repre- 

 sent monstrous involucra of Trifolium repens ; in one case 

 the ovule-bearing margins of the carpel-leaves are not adhe- 

 rent and are clothed with six small leaves ; in the other partly 

 ovules and partly leaves have shot out from the margins. Im- 

 mediately above, in figs. 20 22, M. Turpin gives his explana- 

 tion respecting the formation of the legumen by the cohesion 

 of the convoluted leaves. 



Now, says M. Schleiden, as in the pollen-bearing organs 

 the cellular tissue is converted by a peculiar modification into 

 pollen, so also we observe in the summit of the axis, the nu- 

 cleus, a peculiar modification of this tissue ; for in it is deve- 

 loped a single long cell which is subsequently converted into 

 the sac of the embryo, and this happens at a period long pre- 

 vious to the so-called impregnation. The manifold varia- 

 tions, to which this sac is subject in various plants, are partially 



* Esquisse d'Organographie Wget., &c. PL IV. 



