282 CORALS AND CORAL ISLANDS. 



goes, but having nothing of a pine in its habit. Its long, 

 sword-like leaves, of the shape and size of those of a large 

 Iris, are set spirally on the few awkward branches toward 

 the extremity of each, and make a tree strikingly tropical in 

 character. It grows sometimes to a height of thirty feet. It 

 is well fitted for the poor and shallow soil of a coral island ; 

 for as it enlarges and spreads its branches, one prop after an- 

 other grows out from the trunk and plants itself in the ground ; 

 and by this means its base is widened and the growing tree 

 supported. The fruit, a large ovoidal mas9 made up of ob- 

 long dry seed, diverging from a centre, each near two cubic 

 inches in size, affords a sweetish husky article of food, which, 

 though little better than prepared corn stalks, admits of being 

 stored away for use when other things fail ; and at the Gilbert 

 Islands and others in that part of the ocean, is so employed. 



The Pisonia is another of the forest trees, and is one of 

 handsome foliage and large and beautiful flowers, sometimes 

 attaining a height of forty feet, and the trunk twenty in girt. 



Among the species that are earliest in taking root in the 

 emerging coral debris over the reef, there are the Portulaccas 

 (species of Purslane) ; the Triumphetia procumbens, sl creep- 

 ing, yellow-flowering plant of the Tilia family ; the Tourne- 

 fortia sericea, a low, hoary shrub of the family Boraginaceae, 

 and Sccevola Konigii, a sub-fleshy seashore plant. 



On Pose Island, just east of the Navigator Group, Dr. C. 

 Pickering, of the Wilkes Exploring Expedition, found only a 

 species of Pisonia and of Portulacca. This is a small atoll, 

 under water at high-tide, excepting two banks, one of which 

 is covered with trees. 



In the Marshall Group, on the contrary, where the vegeta- 

 tion is more varied, and the islands have probably undergone 

 some elevation since they were made, Chamisso observed fifty- 



