79 



A Solitary British Member 



of a large family or genus, and is distinguished from all 

 other British ferns by producing two distinct kinds of 

 fronds, one set being dark lucent green, once divided into 

 blunt, closely set teeth or pinnae, and pendant, so that 

 they spread round in a sort of lax rosette ; the other set, 

 which bears the spores, is stiff and upright, longer and 

 narrowed in all parts, so that the teeth are hardly leafy at 

 all and stand much farther apart. On the back of these 

 fertile pinnae are two rows of spore heaps, covered when 

 unripe with a thin skin-like indusium springing from just 

 within the narrow leafy margin on each side. This con- 

 stitutes the difference between Blechnum and Lomaria, in 

 which the edge of the leafy portion itself forms the cover. 

 In Lomaria, too, the fertile fronds are always narrowed, 

 as in our Blechnum, while in many foreign Blechnums 

 and in one British variety this is not the case. B. s. 

 anomalum, not rare in hilly districts, has all the fronds leafy 

 and lax and the spore heaps ranged along the midribs of 

 the pinnae of most of them. In all the other varieties, 

 and as we shall presently see there are many, the marked 

 difference between the two classes of fronds persists and is 

 often emphasized, broad, leafy, widely-tasselled barren 

 fronds being set off by their stiff erect fertile ones with 

 -spiky, many-fingered crests, or it may be, with heavy 

 bunch crests resembling green flowers. 



Some of the Varieties, 



nearly all of which have been found wild, are very striking. 

 The writer's first find in the fern line was B. s. continuum 

 Dvuevy, found in 1881, on a stone dyke on the middle of 

 Exmoor. In this the long, blunt teeth of the barren 

 normal frond are transformed into deeply notched semi- 

 circular short ones, like tiny scallop shells, so that the 

 frond forms two even rows of these from end to end, and 



