MONOCOTYLEDONE^E. 59 



is so completely herbaceous, that it is cut into small 

 pieces, and used as green food for cattle. The Musa 

 is one of the most useful tropical plants, as well for 

 shade, shelter, and forage, as for its fruit, both green 

 and ripe, as food for man. 



The next orders as we ascend are Cannece and 

 Scitammece^ which present no particular physio- 

 logical circumstance worth notice, except that the 

 irregular tubers of several of them are valuable as 

 medicine, condiments, and nutritious food. 



The Orchidece are a remarkable tribe of plants. 

 They inhabit both the torrid and temperate zones. 

 Between the tropics they are mostly epiphytes, grow- 

 ing on the stems and branches of trees, or among the 

 rotten leaves in their shade. Many of them orna- 

 ment the meadows, moist dells, and woods of Europe ; 

 and where they are attractive of the most incurious 

 eye. Their structure is equally interesting to the 

 botanist as to the physiologist ; and though their 

 members are, in most cases, extremely singular in 

 form and texture, their elements are cellular, with a 

 vascular fabric and apparatus. Many of them absorb 

 the whole of their sustenance from the air, especially 

 if it be sufficiently moist : and though they attach 

 themselves to the bark of trees, they are not, strictly 

 speaking, parasites. Some of the American species 

 have curiously jointed stems; and the British Qrchidece 

 exhibit good examples of annual tubers ; (Fig. 26 ;) 

 that is, the new tuber formed last year, comes into 

 flower in this, and when it has ripened seeds, and pro- 



