22 
ASPLENICM. 
whitish lines, varying in number from three to seven, 
on the under surface of the leafits. The whiteness 
arises from a thin covering (called the indusium), which 
bursts with a smooth edge on the side next the mid-vein 
of the leafit. The covering finally peels off, and then 
the sori, which are brown, spread until they cover the 
entire back of the leafit, all but the edge. This spread¬ 
ing, or running together, of the fructification is called 
confluent by botanists. The seed, or spores, are in 
various states of growth from April to October. 
There are two varieties, acuturn (very pointed), and 
obtusum (blunt). The only differences between these 
and the species we have described are that the fronds, 
the leaflets, and leafits of acutum extend to a longer 
and sharper point, whilst those of obtusum, are more 
rounded. The intermediate forms are so various, that 
we really consider the above not entitled even to the 
subordinate distinction of a variety. 
Variegatum is a more certain variation, for it is very 
distinctly variegated with cream-colour. It was found 
on the church of Shottisbrook, in Berkshire, during 
1847, by Mr. Silver. 
The generic name, Asplenium, is derived from a, 
not, and splen, the spleen, alluding to the supposed 
medicinal power of some of the species to lower the 
activity of the spleen. The specific name, Adiantum 
nigrum, is literally translated in the popular title, Black 
Maiden-hair. 
This is one of the common Ferns of the British 
Islands, being found very generally on old walls and 
