THE SEA SPLEENWORT. C9 



ovate or oblong, unequal at the base, the anterior base 

 being much developed, while the posterior appears cut 

 away, with the margin serrated or crenated. The 

 venation is tolerably distinct : each pinna has a mid- 

 vein, giving off veins alternately on either side, branch- 

 ing again into a series of venules. The sori, lying 

 obliquely on the anterior side of each venule, form two 

 rows on each side of the centre ; oblong or linear, with 

 persistent indusia opening along the anterior margin 

 as the spores ripen. The chief variation of the Sea 

 Spleenwort consists in the elongation of its parts, the 

 pinnae sometimes tapering to a narrow point, sometimes 

 also being auricled at the base and deeply lobed. It 

 keeps very close to the sea-level. In cultivation it 

 requires warmth, and grows best in sandy peat-soil, in 

 the interstices of stones or rock-work. 



The Sea Spleenwort is most abundant on the west 

 coast of Europe, extending, however, eastward in the 

 Mediterranean. It is found also on the African coast, 

 in the Western Isles, and, according to Sir W. Hooker 

 in St. Helena. This peculiar distribution has been sup- 

 posed to indicate that it took place prior to the great 

 disruption of the chalk and the vast deposit of allurial 

 mattar along the eastern coast of England. 



HABITATS. Whitehaven, St. Bees' Head, Head of 

 Morecambe Bay, Sea-cave near Silverdale, Piel Castle, 

 Hey sham. 



