520 INTBODUCTION TO CBYPTOGAMIC BOTANY. 



is eaten when prepared in the same way. The soft cellular 

 substance of Gyathea medullaris affords a better article of 

 food, for which purpose some other species are occasionally 

 used. A diantwni Gapillus Veneris is an ingredient in Capil- 

 laire ; but other species, as Aspleniwn Adiantum nigruvi, 

 are often substituted. Nephrodium Filix mas is still used 

 as a valuable remedy for tapeworms. A Polypodium, in 

 Peru, has some reputation in fevers and other maladies ; and 

 the down from the stem of some Gibotium has lately been 

 much recommended as a styptic, under the name of Penghawar 

 Djambi :* its action is probably merely mechanical, as che- 

 mical analysis produces nothing active. A similar substance 

 is gathered in Madeira from Dicksonia Gulcita to stuff 

 cushions. The rhizoma of Phymatodes leiorhiza when dry 

 smells and tastes Hke liquorice. A small species of Gram- 

 mites is so odoriferous when dry, that it is used by the Indian 

 women of Peru as an agreeable perfume. 



588. It remains only to say a few words on fossil ferns. 

 Ferns abound in the coal measures and in some other forma- 

 tions ; but they very rarely bear fruit, and are therefore not 

 capable of identification with our own. The species are appa- 

 rently very numerous. Dr. Hooker has shown, in the Memoir 

 quoted above, how impossible identification is from the vena- 

 tion only, and instances the rarity of fruit in the tree ferns of 

 New Zealand as a circumstance in favour of the supposition 

 that many of them were arboreous. Trunks of tree ferns are 

 found in a very perfect state, according in structure perfectly 

 with our own. Corda figures some with comparative analyses 



objection, however, to this as an article food is the nauseous mucilage. 

 If the rhizoma, after being washed and peeled, is scraped so as to avoid 

 including the hard walled tissue, and then mixed with a sufficient quan- 

 tity of water, the mucilage will be dissolved, and after a few hours may be 

 decanted. A little colourless, tasteless mucilage will pass off on a second 

 washing, and the residue, when baked, is far fi-om unpalatable, and 

 must be very nutritious. It is far better than Cassava Bread, and would 

 not be despised in time of famine. See also Hook. Him. Journal, i., 

 p. 293. 



* Pharm. Journ., Nov. 1856 ; Chemisohe Untersuchungen des Peng- 

 hawar Djambi in Vierteljahresschief fur prakt. Pharm., vol. 5, 1856. 



