80 HISTORY OF BRITISH PERNS. 



each lobe, or if the frond is not lobed the stipes is continued 

 upwards in the form of a vein ; this becomes forked so as 

 to send up one vein to each of the teeth into which the 

 part is divided ; and three or four linear sori are produced 

 in a very crowded manner within this small space, so that 

 when from age the sori burst open the indusiurn, the spore- 

 cases form a confluent mass over the whole under- surface. 



The confluent mass of spore-cases arising from the 

 crowded position of the sori, has led some authors to consider 

 this plant an Acrostichum, the mark of which is to have the 

 whole under-surface thus covered. Some of the sori being 

 face to face, and almost in juxtaposition, has again led other 

 botanists to think it a Scolopendrium, the mark of which is 

 to have the sori confluent in pairs face to face ; but if the 

 plant is examined while young, it will be seen that these 

 resemblances are unreal, and that it is really an Asplenium. 

 It is thus that it has been called by the names of Aero- 

 sticjium septentrionale and Scolopendrium septentrionale ; to 

 which Amesium septentrionale has to be added as another 

 synonyme. 



In cultivation it requires sandy peat-soil, and the shelter 

 of a close frame, or bell-glass. 



ASPLENIUM TRICHOMANES, Linnaw. The Common 

 Spleen-wort. (Plate XIII. fig. 5.) 



