10 HISTORY OF BRITISH FERNS. 



nately, the venules being again branched, and the veinlets 

 anastomosing more or less near the margin. The sori are 

 borne along the sides of the venules in a very irregular 

 manner, the majority of them being directed towards the 

 apex of the pinna ; at first the sori are quite concealed by 

 the scales, but the spore-cases ultimately protrude between 

 them, although, being very similar in colour, the latter are 

 never very obvious. 



The Ceteracli is a mural species, occurring on the walls 

 of old buildings and ruins, and in rocky places. It is 

 pretty generally distributed in the United Kingdom, but is 

 considered somewhat rare in Scotland. It occurs also 

 throughout central and southern Europe, and in the north 

 of Africa. 



Like other wall Ferns, this is often difficult to establish 

 in cultivation when first transplanted ; but when once this 

 is overcome its cultivation is not difficult. It is best grown 

 in a cold frame, potted rather high, among loam mixed with 

 a large proportion of brick -rubbish, and not over- watered. 

 Though generally found in exposed and rather sunny situa- 

 tions, the finest examples we have seen were found in a 

 shaded, moist situation, under trees, where sunshine never 

 visited them. 



