FLOWERING PLANTS OF THE GREEN LANES. 227 



Arum is ill many respects a very peculiar plant. The 

 corn (a), or root as K . 



we should call it, 

 is really an under- 

 ground stem, which 

 contains a large 

 quantity of starch 

 that has heen mis- 

 used in commerce 

 for the purpose of 

 adulterating arrow- 

 root. In the early 

 history of the plant 

 there appears a 

 convolute leaf (&), 

 which eventually 

 opens after hav- 

 ing sufficiently pro- 

 tected the spadix 

 and its remarkable 

 cluster of flowers. 

 For some hours after 

 the opening of the 

 spathe, the heat 

 evolved may be felt 

 by the hand, or 

 tested with an ordi- 

 nary thermometer. 

 The leaves are very Cuck Pint (Arum """**"> ' -' 

 acrid, and are sometimes mistaken by children 



Q 2 



