IOWA ACADEMY OF SCIENCES. 93 



PELL^A ATROPURPUREA, LINK.. ON SANDSTONE LEDGES IN 

 MUSCATINE COUNTY, IOWA. 



BY F. KEPPEKT, MUSCATINE, IOWA. 



There are in Muscatine county two localities where this fern occurs. 

 These stations are sandstone ledges belonging to the carboniferous forma- 

 tion. This seems to be an exceptional and as yet uni'ecorded habitat for 

 this fern. These localities are both along the Mississippi river, the one at 

 Wyoming hills, seven miles, the o.her at Moutpelier, fourteen miles above 

 Muscatine City. 



The sandstone composing these ledges is soft, more or less shaley, par- 

 ticularly that at Montpelier. That these ledges are natural drainage points 

 is evidenced by the facts that at both are found living springs and a more or 

 less wet condition along neaiiy the full length of their exposure. In places, 

 at the base of each of these ledges, tufa is found in limited quantity. These 

 evidences indicate the presence of lime, which is confirmed by chemical 

 tests, both the water and the stone showing the presence of a considerable 

 per cent of this base. The lime may not be an original constituent of the 

 rock, but a secondary addition, resulting from the lime-charged waters 

 which filtrate into these ledges, supplying the necessary lime and moisture 

 which make these sandstone ledges congenial to this fern. 



In "Ferns of North America," by D. T. Eaton, it is stated that "this 

 fern was collected by John Clayton about 1736, on the shore of the river 

 Rappahannock, in a shady place by the root of a juniper." 



It may be worthy of mention that at both of the Muscatine stations for 

 this fern the red cedar ( Junipcrus virginiana, L.) is found on the brinks 

 of the ledges. These are the only known places in the county where the 

 juniper is found native. 



