BLACK MAIDEN-HAIR SPLEENWOET 67 



duced near the junction with the midvein, that is to 

 say, near the centre of every lobe or pinnule. All the 

 ultimate divisions of the fronds, as well as all the 

 larger lobes, have midveins with these simple or 

 branched venules. When young, the sori are distinct 

 and of the elongated narrow form common to the 

 genus, but, growing older, they spread till they often 

 become confluent and cover the entire under-surface of 

 the frond. The indusium is narrow, its margin free 

 and entire ; but it is soon lost, being pushed away by 

 the growing sori. This species is very variable : in 

 dry and exposed places small and obtuse, in more 

 sheltered drawn out and elongated. These extreme 

 states are ranked as varieties. Some have been found 

 also with the fronds variegated with white. It seems 

 to be nearly as common as the Athyriums, though not 

 .growing to so great an elevation, for it is found nearly 

 everywhere, from Scandinavia to the Cape of Good 

 Hope, in the Sandwich Islands, in Afghanistan, in 

 Java, and in St. Helena. It thrives moderately well 

 in cultivation if planted in a sandy soil and well 

 drained ; and is easily manageable as a pot-plant, but 

 requires a pure atmosphere. It is common throughout 

 the Lake Country, either on the slate or limestone, 

 often preferring old walls. 



VARIETIES. 



intermedium, Heversham, J. M. Barnes. 

 depauperatwm, Winder in ere, P. Clowes. 

 acuti-dentatum, Witherslack, J. Crossfield. 



F2 



