386 BOTANY. 



when cultivated,, they trail on the ground as long en- 

 tangled vines. Their esculent roots are very large and 

 shapeless, have a rough brown exterior, and are white and 

 solid within ; they furnish a good vegetable supply for 

 sea-stock, and are the best substitute for the potatoe. 



Pitcairn Island. Society and Sandwich Isles ; native 

 name uhi. Marquesas. Timor. St. Helena. 



(Two other species of Dioscorea obtain at the Society 

 Islands : the one, called patdra, infests the thickets of 

 both low and elevated lands, and is usually entwined 

 around the trunks of trees. It has ternate leaves, and 

 bears bulbs - on its stalk j the root resembles a potatoe, 

 and is eaten by the natives when other vegetable food 

 is scarce. The second species is called hoi. It re- 

 sembles the preceding in growth and habitat, and is 

 alike viviparous, bearing in the axillse of its leaves, 

 muricated bulbs, the size and shape of an Aleppo gall- 

 nut, and of a fawn-colour. The root of this plant is 

 also eaten by the natives, in times of scarcity.) 



DICECIA. DECANDRIA. 



Carica papaya. The Papaw. This fruit-tree, al- 

 though a common denizen of most tropical lands, is not 

 indigenous to Polynesia, but has been introduced to 

 many of the islands by European navigators. We 

 noticed the species chiefly at the Marquesan and Society 

 groups, where it grows on the coast with indigenous 

 vigour. 



The Papaw usually attains the height of about fifteen 

 feet, and has an elegant style of growth, the trunk being 

 slender, straight, and unbranched till near its summit. 

 The leaves are large but light, supported on very long 

 foot-stalks, and have nearly the form of the common 



