190 CONSERVATIVE ORGANS. [LECT. V. 



until they find another plant to lay hold of, and 

 into which they can dip their caulinar roots, or 

 rootlike absorbents, which are protruded from the 

 stem, in order to share its nutriment, and on 

 which they are afterwards supported ; as, for ex- 

 ample, the Cuscuta, or Dodder *, which may be 

 regarded as the natural parasite of our indigenous 

 Heaths and Hops. 



Some plants, after they have arrived at a cer- 

 tain age, do not even require that their roots 

 should be fixed to any spot ; but maintain life on 

 what they can procure by absorption from the at- 

 mosphere. Such are the Cacti, a curious tropical 

 tribe of succulent plants ; on which account one 

 of the species, the Indian Fig, Cactus opuntia, 

 was recommended to the notice of seafaring 

 people, by the late Dr. Anderson of Madras, for 

 the purpose of supplying vegetable food on long 

 voyages ; and as a preventive of scurvy. But the 

 most curious instance of this kind is the aerial 

 flower, Epidendrum flos ae'ra-f-, an East Indian 

 parasitical plant, which continues to grow, blos- 

 soms, and even perfects its seed, when it is torn 



* The Dodder germinates in the earth, and rising above it, 

 shoots out filiform stems, which twine around the neighbouring 

 plants. Its original root now decays, and a kind of warty roots 

 are formed in the stem at every point where it touches the sup- 

 porting plant by which it is nourished. 

 Aerides matutinum of Willdenow. 



