THE ASPLENIA 



6* 



does not present a single character peculiar to that genus. The 

 distinguishing fructification of the genus is the arrangement of the 

 spore heaps or sori in definite lines, short or long, arranged herring- 

 bone fashion on each side of the midribs of the divisions, resembling 

 what we may see on a large scale in the Hartstongue (Scolopendrium 

 vulgar e), which is a near relation, but has the lines arranged in faced 

 pairs, the two heaps coalescing into one when ripe. These linear 

 heaps are provided when young with a transparent whitish cover, 

 (indusium), springing from one side. By this character any fertile 

 Spleen wort is easily recognizable. This arrangement is very clearly 

 shown by Fig. 34. The Spleenworts are thoroughly evergreen, and 

 are more at home in old walls, rock crevices, and stony dykes than 

 in the soil proper, and, in fact, it is only in such positions that our 

 native species occur. As regards variation, the genus generally 

 is little prone to depart from normal types, and especially to assume 

 tasselled forms, and it is therefore somewhat singular that several 

 of our native species have done so on rather a generous scale ; 

 several, on the other hand, have not " sported " at all, or at any rate 

 have done so on so indifferent a scale that we may well ignore the 

 exceptions. Culture, as may be gathered from the nature of their 

 habitats, involves perfect drainage, a rubbly, open compost, in- 

 cluding some old mortar and porous stone, intermingled with 

 leaf mould, and a little loam and sand. On rockwork they should 

 be installed in chinks, and not in flat beds, and very close culture 

 is not advisable. With these remarks 

 we may now proceed to treat of the 

 species seriatim. 



asplenium adiantum-nigrum 

 (The Black Maiden-hair 

 Spleenwort) 



(Plate IV) 



This member of the Spleenwort 

 family is one of the commonest and 

 most widely spread. It is found in 

 abundance in many places, on old 

 walls, in stone dykes, and in hedge- 

 banks, in which the fronds are some- 

 times between one and two feet in 

 length, including a very long stalk, 

 such length being due to the Fern 

 projecting its fronds from very deep 

 chinks. For culture a larger admix- 

 ture of leaf mould is advisable than 

 for other Spleenworts, and Mr. G. B. 

 Wollaston advised an admixture for Fig. 23. Asp. ad. nig. (pinna). 



