OKCHIL OF ECONOMIC PLANTS. 301 



in one year. At Nice, where tte Orange flourislies in the open 

 air, a tree is recorded to have grown to the height of 50 feet, 

 with a trunk that required the arms of two men to embrace it. 

 The Orange also attains a great age even under artificial culti- 

 vation ; one growing in a box at Versailles, in Prance, is said 

 to have been sown in 1421. The wood of the Orange resembles 

 boxwood in density and colour. The tree has become naturahsed 

 as well as cultivated in the United States, especially in Florida, 

 where there are extensive groves, occupying a tract of country 

 between the latitudes 2T and 29° North, which is said to contain 

 20,000,000 trees, and vast quantities of the fruit are sent to all 

 parts of the United States, but the quantity falls short of the 

 demand. Large quantities are imported from Sicily, and even 

 from the island of Tahiti, from whence in 1869 eleven vessels, 

 having a total tonnage of 1468 tons, conveyed cargoes of oranges 

 to San Francisco, and fiom thence by rail they are distributed 

 throughout the United States, even to the towns of the Atlantic. 

 Orange trees have within the last fifty years been introduced 

 into and cultivated with success in the Australian colonies. 



Orange-root. (See TeUow-root.) 



Orchil {BoGcella tinctoria), a foliaceous species of Lichen, 

 growing in tufts on rocks. It is from 2 to 6 inches long, and 

 varies much in breadth, which has led to several of the more 

 distinct forms being regarded as species. It is fonnd in all parts 

 of the world, conducive to plant life, even on the dry rocks of 

 Aden, and is abundant on the rocky shores of this country, 

 often growing on perpendicular cliffs, from which situation it is 

 collected, men being lowered with ropes for that purpose. It 

 has been extensively used in dyeing, and originally it formed a 

 valuable article of commerce. The average annual imports 

 amounted at one time to 6000 tons, but like many other things 

 of the past, lichen dyes are now being superseded by fine 

 dyes obtained from coal-tar. The delicate chemical test called 

 Litmus is obtained from this and other lichens. 



Many other lichens resembling the Boccella in habit, but 

 growing on trees, are found in this country. Ramalina fraxinea 



