80 THE GEOGRAPHY OF PLANTS. 



torrid zone, though it will grow on the Andes at 

 from 9,800 to 13,000 feet above the level of the 

 sea, nor will it grow further north than Iceland. 



In the West Indies, the arrow-root plant 

 (Maranta arundinaced) is cultivated to a great 

 extent, but it is a native of equinoctial South 

 America. The best is brought from the Ber- 

 mudas, in the sub-tropical zone, 32 N. lat.,but 

 large quantities are also imported from St. 

 Vincent's. The South Sea arrow-root, which the 

 late rev. J. Williams first introduced into this 

 country, is the produce of a tuberous-rooted plant 

 of quite a different character, (Tacca pinnatifida.) 

 The arrow- root, as used in England, is the 

 farina or starch obtained from the root, by 

 washing the rasped or pounded tubers in water. 

 It is said to owe its name to the belief of its 

 being an antidote to the poison of the arrows 

 of the Indians. Sugar, which is the principal 

 produce of the West India Islands, we have 

 described under the equinoctial zone. Pimento, 

 or allspice, is the only spice which occurs 

 naturally in the West Indies, and it is remark- 

 able, that though not a single plant has been 

 raised by sowing the seed, yet self-sown it mul- 

 tiplies exceedingly. 



In these islands also is found the dumb-cane, 

 (Diefenbacliia seguina^ one of the arum tribe. 

 It grows to the height of a man, and has the 

 property, when chewed, of causing the tongue to 

 swell, and thus destroying the power of speech. 

 Hooker relates an account of a gardener, who 

 incautiously bit a piece of the dumb-cane, when 



