COMMON PELLITORY OF THE WALL. 



Parietaria officinalis. 



Class Tetraxdeia. Order jNIonogyxia, Nat. Ord. Urtice^. 

 Nettle Tribe. 



Our old walls are often made verdant by the 

 Pellitory. As Knapp has observed, it may be 

 seen in such places seeking the calcareous nitrate 

 found there, this salt appearing essential to its 

 vigom' and health. Large masses of the plant 

 may be found on rocky places near the sea, in 

 some spots almost lying over the surface on 

 which it grows, in others rising erect and 

 branched, a foot and a half in height, and 

 losing much of the downy covering which 

 invests both the flower and foliage of the 

 smaller specimens. The little reddish-purple 

 blossoms crowd closely between the stem and 

 leaf, and appear on the plant from June to 

 September. The manner in which the sta- 

 mens shed their pollen, or yellow powder, is 

 very singular. These minute threads, on their 

 first appearance, all bend inwards ; but no 

 sooner is the pollen matured and fit to be 

 discharged, than the warmth of the sun, the 

 hght tread of an insect, or the smallest touch 

 with the point of a pin, makes them fly back 

 and throw out a little cloud of dust- This 

 elasticity is owing to the jointed structure of 



