132 



of the female cone of the Conifers are very different from 

 those just mentioned; he considers that which has been re- 

 garded since R. Brown as an open ovarium to be merely a 

 scale-like expanded placenta, and R. Brown's bractea to be 

 the actual carpellary leaf. In fact the placenta shows itself to 

 be in the Abietinece a perfectly independent part in its growth 

 from the carpellary leaf, and perfectly distinct. Nay, it here 

 developes itself, when without the least constraint, to such an 

 extent, that at length the carpellary leaf itself (bractea of 

 authors) appears as a mere supplementary part. The detailed 

 exposition of this highly difficult subject M. Schleiden pro- 

 mises at some future time. He too found an hermaphrodite 

 cone of Pinus alba, and states that these views are confirmed 

 by this monstrosity in the most beautiful manner. 



I have very frequently found hermaphrodite cones, and the 

 transformation of the actual spicular leaves into carpellary 

 leaves or into bracts of authors, may most distinctly be fol- 

 lowed on them, as well as the origin of anthers from the leaves 

 which surround the base of the cone. 



On Phenomena of Sensibility and Irritability of Plants. 



In a memoir with the title ** De la tendance des vegetaux 

 a se diriger vers la lumiere et de leur tendance a la fuir", 

 which M. Dutrochet has published in the collective edition of 

 his memoirs*, various very obscure phenomena of the direc- 

 tion and motions of some plants and their parts have been 

 investigated. The learned author begins this chapter first 

 with the consideration of the direction of the roots in the ger- 

 minating mistletoe (Viscum album),, and arrives at results al- 

 ready known. The greatest portion of the memoir is occu- 

 pied with the consideration of the direction of the root in 

 creeping plants, and the causes. M. Dutrochet has observed 

 that some plants, for instance Humulus Lupulus and Convolvu- 

 lus sepium, avoid the light, while others constantly turn to- 

 wards it. The stems of these two plants were placed in a glass 

 with water, and observed near a small window 7 . The apices 

 of the stems were directed in the morning towards the win- 

 dow, but in the course of the day turned from it, while at 

 night they returned to their original position. With the fading 



* Vol. ii. p. 1640. 



