LECT. XI.] CAULINAR AND FOLIAR APPENDAGES. 643 



" exceedingly transparent, and hollow from top 

 " to bottom ; the other, a little bag more pliable 

 " than the bodkin, and within it a cellular struc- 

 " ture, which contains a thin transparent liquid." 

 In figure 21, Plate 9, a. represents the hollow 

 bristle, with a drop of fluid hanging upon its 

 point; b. the cellular bag or sponge which con- 

 tains the poison, and in which, also, it is pro- 

 bably secreted. When the bristle penetrates the 

 skin of the finger, or any other part of the 

 body, it is pressed down upon the sponge, from 

 which a quantity of the liquid is thus squeezed, 

 and rising in the tube, is ejected and depo- 

 sited beneath the skin, causing the inflammation 

 and painful irritation which succeed. 



2. The spindle-shaped bristle ( seta fusiformis) 

 is, as its name implies, thickest in the centre and 

 acuminated at each end. It lies parallel to the 

 surface of the leaf, to which it is fixed by a very 

 short footstalk (Plate 9, fig. 22) ; is hollow, and 

 contains a coloured liquid, which apparently 

 enters it through the footstalk : but I have not 

 been able to discover any opening in the bristle, 

 through which it could be ejected, as in the sting 

 of the Nettle. This form of bristle is peculiar 

 to the genus Malpighia, at least I have never 

 met with it on any other plants. 



b. Compound bristles (setce composites) are 



TT2 



