36 PALMER : 



Much resembling the walking- leaf is the pinnatafid spleen- 

 wort, Asplcniuin pinnatifidum. This species is to the manor 

 born. Nuttall discovered it on the banks of the Schuylkill 

 above Philadelphia in the year 1818. It has since been found 

 in other places in Pennsylvania, as also in New Jersey. Its 

 range is now stated as " New Jersey and Pennsylvania to 

 Illinois, south to Georgia, Alabama and Arkansas." (Britton 

 and Brown). It is much less frequent than the walking leaf. 

 Unlike that species, also, it habitually grows in the smallest 

 of cracks on the faces of bleakest rocks. This, however, is 

 possibl)^ not a preference on the part of the fern. There is some 

 reason to think that the plant is still more lacking in strenuos- 

 ity than the walking leaf, still less able than it to withstand 

 the encroachments of more vigorous species like the rock poly- 

 pod, and so is forced to find foothold in the most restricted 

 of unoccupied teiTitory. You shall find it, if at all, in the 

 most improbable places. In Fayette county, Pennsylvania, 

 two years ago, Mr. Crawford, of Philadelphia, detected it 

 upon the bleakest, the most sun-scorched rock in the vicinity. 

 Rocks there were by the thousands, about the slopes of the 

 vale, many of them ideally sheltered from the intensest cold 

 of winter and the extreme heat of summer. On them, or 

 some of them, were to be seen the walking leaf, the mountain 

 spleenwort, and others, but no A. pinnatifidum. In 1880, in 

 company with the late Lewis Palmer, the writer had the 

 extreme pleasure of finding it very nearly in the place of its 

 botanical origin. It grew at that time out of the smallest 

 possible crack in the face of a bare and overhanging rock on 

 the west side of Wissahickon creek. The rock at that point 

 is a much-contorted mass of Wissahickon gneiss. Again, in 

 1895, during a lonely scramble along Ridley creek, in Dela- 

 ware county, the writer saw a single flourishing example, 

 situated in the smallest of cracks, on the barest of rocks, 

 where it was exposed to the direct rays of the sun nearly half 

 of each day. (Here again the rock is Wissahickon gneiss). 

 This plant was watched for years. It spored profusely, and 



