160 THE ROCK SPLEENWORTS. 



the backs of the ordinary fronds in a single row near the 

 edge of each pinnule, the individual sori oblique to the 

 rachis. 



In size, shape and habitat, this species seems to stand 

 halfway between the maidenhair and ebony spleenworts. 

 It was once considered a variety of the latter and is 

 sometimes called the little ebony spleenwort. The points 

 by which it may be distinguished from the maidenhair 

 spleenwort have been mentioned. It may be well, also, to 

 contrast it with the ebony spleenwort. For all their re- 

 semblances, it will be found upon comparing the two that 

 they have very little in common. 



In parvulum the fronds are small, thick, stiff, with en- 

 tire, deflexed pinnae. Fertile and sterile fronds are of the 

 same size. 



In ebeneum the fronds are larger, thin, flexible, with 

 serrate horizontal pinnae and the fertile fronds are much 

 the taller. 



Asplenium parvulum is found from Virginia and Kan- 

 sas south and southwestward to the tropics. In the 

 mountains of Jamaica it frequently grows on wayside 

 banks and old stone walls, often in full sun. 



The Ebony Spleenwort. 



The ebony spleenwort (Asplenium ebeneum) loves the 

 rock as much as any of its kin, but only rarely is it 

 found on the shelving sides of cliffs. I have found it 

 thus along the Palisades of the Hudson, but it had evi- 

 dently strayed down from its home at the top. It espe- 

 cially delights in thin stony soil and comes to its best in 

 half wooded lands in a tangle of small bushes, brambles 

 and clumps of the New York and boulder ferns. It also 



