CULTIVATION. 849 



practice of potting, it is a rule with many gardeners 

 to remove all the old drainage crocks, the centre thus 

 becomes a mass of soil, which in time becomes com- 

 pact, inert, and useless, liable to become stagnant, 

 and in time causing th.6 plant to sicken. This is 

 avoided by preparing and retaining the old drainage. 

 This mode of drainage is, however, only necessary for 

 plants required to be permanent in botanical collec- 

 tions. Its utility in prolonging life is verified by some 

 yet existing plants of Pruteacece at Kew, some of 

 which are forty, and others above sixty years of age. 

 What has here been stated may be considered as a 

 general rule for the greater number of the Fern 

 family, such as are usually found in ordinary collec- 

 tions of a hundred species, more or less. But in this 

 extensive family there are many possessing some pecu- 

 liar nature, and a few examples of these require to be 

 specially noticed. 



The group which has been termed Epiphytal, 

 consists of the genera Davallia, Goniophlebium, 

 Drynaria, Phymatodes, Pleuridium, Platy cerium, Lo- 

 mariopsis, Polybotrya, and others of like habit, charac- 

 terized by a true and highly-developed rhizome or 

 sarmentum, generally creeping, and adhering by 

 their fine fibrous roots to the surface on which they 

 grow. Their positions in their natural homes are 

 generally on more or less perpendicular surfaces of 

 moist and shaded places of rocks or ordinary soil, 

 where decomposing vegetable matter abounds as a 

 surfacing. They are often found on trees, and with 

 many species of Polybotrya and Lomariopsis this 

 seems to be their true position, and often by their 

 vigorous growth, the trees are clothed with them in 



