646 CONSERVATIVE ORGANS. [LECT. XI. 



pedicles of fragrant sharp-leaved Mint, Mentha 

 acutifblia. In these and similar instances the 

 direction forms essential distinctions in the spe- 

 cific characters of the plants. Indeed, Sir E. 

 J. Smith, speaking of the direction of the hairs 

 about the calyx and flower-stalk in the Mint tribe, 

 says, " I have found it the only infallible distinc- 

 " tion between one Mint and another." Hairs are 

 said to be ascending (ascendentes) when they are 

 directed towards the summit of the part on which 

 they are seated ; descending ( dependent es) when 

 towards the base; and appressed (adpressi) when 

 they are closely applied lengthways to the part, as 

 on the peduncle of long smooth-headed Poppy, 

 Papaver dubium, which is distinguished from the 

 common red Poppy chiefly by this character. A 

 very curious effect of the direction of hairs is per- 

 ceived in the pitchers or ascidia of Sarracenia, 

 and in some tubular flowers. The stiff hairs, in 

 these instances, by pointing inwards and towards 

 the bottom of the cavities in which they are found, 

 perform a service similar to the wires which point 

 inwards at the mouth of a mouse-trap, preventing 

 insects which enter these cavities from escaping 

 out of them. 



With regard to the uses of the hairs, some 

 Phytologists have considered them to be trans- 

 spiring and absorbing organs. I have already de- 

 monstrated that the cnticular pores are the trans- 



