PHYSIOLOGICAL BOTANY. 263 



The curvature of stems towards the light will be re- 

 ported upon in an article in which the general action of 

 light upon plants will be discussed. Dutrochet has made 

 some observations upon the movements of the free points 

 of plants furnished with tendrils, which were spoken of in 

 the previous Annual Report. In the Compt. rend., 1844, 

 ii, 295, there are some observations, by the same author, 

 upon the Movements of the free Points of twining Plants. 

 They take place in the same direction as that in which 

 the stem coils itself. Dutrochet connects them with the 

 spiral position of the leaves. In Solanum Dulcamara the 

 winding of the stem is sometimes from right to left, some- 

 times the reverse, and the spiral of the leaves is double. 

 I shall here merely observe on this point, that Mohl has 

 already observed the curvature of both the stem and 

 the tendrils when unsupported. Dutrochet also gives 

 the times in which the turns are completed ; but they do 

 not appear to be very constant. 



Dutrochet has also made the observation, that in Epilo 

 bium molle Lam., (E. parviflorum Schreb.) some of the stems 

 grow directly into the earth, like roots. They are thicker 

 than the upright stems, and are furnished with more 

 cortical substance, which Dutrochet ascribes to their de- 

 scent into the earth, or rather the thickness of the cortical 

 substance arises from the moisture of the earth. (See 

 Compt. rend., 1845, ii, 1186.) 



Boucherie reports, that sections of wood prepared by his 

 method (see Annual Report for 1840, pp. 360, 384), kept 

 sound in the earth for three years, whilst other unpre- 

 pared sections of the same wood entirely rotted in the 

 same place. Compt. rend._, 1845, ii, 1153. 



As regards WYDLER'S Morphological Communications, 

 Bot. Zeit., 1844, 641, 657, 688, 705, I shall merely 

 remark, that they do not permit of condensation into the 

 form of an abstract. The author there assumes, as his 

 basis, an ingenious method of explanation, which was 

 proposed by Al. Braun (Flora, 1842, 694). But other 



