4 THE AMERICAN BOTANIST 



the stately proportions of the justly famous Norfolk Island 

 tree ferns. These belong- to the species Alsophila excelsa, and 

 are frequently from sixty to eighty feet in height. 



Chamisso's tree fern, hapu, is more abundant, and more 

 widely distributed than its larger relative. It occurs on all 

 of the high islands of the archipelago 1 , and is plentiful in the 

 humid lower and middle forest zones. Its trunk is usually 

 but six or eight feet in height, and its crown never equals the 

 magnificent dome of the ha pit i'i'i. Under very favorable con- 

 ditions the trunk may rise to fifteen feet, but this size is 

 exceptional. 



The popular notion that tree ferns are tender and easily- 

 damaged is derived from kinds quite different from the hardy 

 hapu. The tree ferns possess great vitality, and will reju- 

 venate themselves after repeated injuries. The Hawaiian 

 Cibotiums are able to maintain themselves in many districts 

 overrun by cattle, goats and swine. These half-wild herbivores 

 have irreparably damaged much of the native w-oodland, but 

 have not so seriously injured the tree ferns. The wild pigs are 

 particularly obnoxious by reason of their rooting habits, and 

 undoubtedly destroy considerable quantities of young fern trees. 

 The pig hunters well know that fern groves are the favorite 

 haunts of their game. 



The large petiole-bases, and the terminal bud, (which is as 

 big as a man's head), are densely covered with a thick matting 

 of golden-brown hair. This soft, silky substance is called pulu 

 by the natives. Under the microscope the individual hair is 

 seen to consist of a series of flat, thin-walled cells, large at the 

 base and tapering to a slender apex. In the early days pitlit 

 was exploited commercially as a stuffing for pillows and mat- 

 tresses. Several hundred tons were annually exported t<> Cali- 

 fornia, in addition to the large local trade. 



