PROPERTIES AND USES. 387 



Polystichum coriaceum. 



This is common to many countries. In Chili it is one of 

 the plants termed Calahula, and like the others is reputed 

 for the cure of syphilis. 



Nephrolepis tuberosa. 



This is a native of Nepaul. It produces underground 

 tubers like small potatoes, which are used for food by the 

 natives. 



Alsophila excelsa. 



A native of Norfolk Island, which when first discovered, 

 abounded in examples of this Fern, averaging in height 

 from 25 to 50 feet, or even, it is said, 80 feet. The centre 

 of the stem contains a white pith, in consistency resembling 

 a yam, which is greedily eaten by hogs ; it is also common 

 to the Fiji and other islands of the Pacific. The stems are 

 much used for building purposes, being hard and fire-proof, 

 and lasting an incredibly long time ; it is also cut into 

 ornamental forms, and placed round tombs. 



A. australis is a native of Tasmania ; it grows in gullies 

 on Mount Wellington at an elevation even reaching the 

 snow-line ; its stems are used in the same manner as the 

 preceding. 



CyatJiea medullaris. 



A fine tree Fern ; a native of New Zealand, Queensland, 

 and Pacific Isles. The interior of its trunk contains a soft 

 mucilaginous pulp, which may be compared to sago ; it is 

 extensively used as an article of food by the natives, to 

 obtain which fine trees are cut down. 



