132 Walking Leaf 



undulate or irregiuar or rarely incised: midribs prominent be- 

 neath: surfaces glabrous: color deep, lustrous green, or yellow- 

 ish-olive in age or in plants exposed to the sun: texture cori- 

 aceous or subcoriaceous. 



Venation pinnate, anastomose: marginal veinlets largely free. 



Sori linear, straight or curved, variously placed along veins, 

 some solitary, some confluent with ends of others, some conni- 

 vent, usually outwardly, or simply faced in pairs: indusia whitish, 

 delicately membranous, undulate at margin, attached at sides 

 or around outer ends of areolae or at leaf's margin to free veinlets, 

 those next midrib opening toward it, many of the outer opening 

 toward each other in pairs. 



Spores ovoid, with winglike pellucid crenate margin. 



Habitat. Limestone, gneiss, granite, quartzite, sandstone, 

 shale, and serpentine.* On cliffs, boulders, etc.,f usually on 

 shaded sloping rock coated with mossy earth. Over this the 

 leaves stretch, crossing one another: in the interstices the pro- 

 liferous tips of new leaves are inserted. 



Range. Maine and southern Quebec to Minnesota, south to 

 Georgia, Alabama, and Kansas. 



Camptosorus rhizophyllus (Linnaeus). Link, Hort. Berol. 2: 69. 1833. 

 Asplenium rhizophylla. Linnaeus, Sp. PI. 1078. 1753. 



THE leaf first produced by the plant springing from the 

 proliferous tip of a mature leaf of Camptosorus rhizophyllus 

 often, if not always, represents a higher degree of leaf-develop- 

 ment than the first produced by the plant springing from the 

 prothallus. The blade of the latter leaf is either spatulate, ob- 

 cordate, or obreniform: if spatulate, a leaf with an obreniform 



* See Fern Bulletin, 8:92, 1900. Also D. C. Eaton, N. Am. Ferns, i =56. 1878. 

 t In the limestone region of Vermont I have seen this plant lining the mouth of an 

 old well. 



