322 ■FEENS: BillTISH AND FOEEIGW. 



witli farinose fronds, commonly called Gold and Silver 

 Fema, are also very susceptible of moisture; they 

 should never be syringed, or water allowed to fall on 

 their fronds, as the- farina, being loose, is distarbed by 

 the water, and running down, gives the appearance as 

 if the plants were smeared with dust. They, howeve^, 

 differ from the preceding, requiring more light, and 

 the temperature of the Tropical House. The species 

 of Gymnogramma vary very much in habit, as regards 

 size and circumscription of the fronds, G. trifoUata 

 having fronds from three to, four feet high, while in 

 G. chaerojphylla and G.leptophylla^ej are fragile, and 

 average from two to six inches in length. These two 

 species are peculiar in being, with the exception of 

 Geratopteris thalictroides, the only known truly annual 

 Ferns. G. elicBropliyUa grows freely ; its spores vege- 

 tate abundantly throughout the house, often as a 

 weed. G. leptophylla is, however, not so free in its 

 growth. When its fronds decay, ' the pot should be 

 covered with a piece of glass, and put in a dry place 

 until the proper season arrives in spring, when the 

 apphcation of moisture will cause the latent' spores to 

 vegetate. G.flexuosa differs from, the whole of the 

 "genus in having prolonging fronds, which climb in a 

 rambling manner over bushes, like those of Lygo- 

 dium, noticed in another page : it will probably lief e- 

 after form the type of a distinct genus. The beautiful 

 genus LindsoBa, of which no less than sixty species are 

 described in Hooker's " Species Filicum," are, with 

 few exceptions, natives of the tropics of both hemi- 

 spheres; in my Catalogue of 1857, only two species are 

 recorded as being cultivated ; but, within these few 

 years, the number has increased to fourteen, the greater 



