38 American Midland Naturalist Monograph No. 2 



9. PoLYPODiUM L. — Polypody 



1. Leaves glabrous; rocky ledges, locally abundant. [P. yiilgare of auth., not L.} 

 P. virginianum L. 



1. Leaves scaly beneath; on trees, rarely on rocks; Jackson Co., and southw. 

 [Acrostichiim polypodio'ides L., ex p.; P. polypodioides (L.) Watt, var. 

 michauxianum Weatherby] P. ceteraccinum Michx. 



10. CampTOSORUS Link 

 C. rhizophylUis (L.) Link. Walking Fern. Moist rocky ledges, not rare. 



IL AsPLENiUM L. — Spleenwort 

 1 . Rachis green, flat. 



2. Leaves pinnatifid, or pinnate below, lanceolate, tapering to a long narrow 

 tip, the segments obtuse, crenate; sandstone cliffs, rare, s. III. Pinnatifid 

 Spleenwort A. pinnatifidiim Nutt. 



2. Leaves 2-3-pinnate, rhombic in outline, the segments cuneate, finely 



toothed at apex; usually on calcareous cliffs; s. 111., without definite 

 locality, Brendel. \_A. ruta-muraria of Am. auth, not L.] Rue Spleen- 

 wort A. cryptolepis Fern. 



L Rachis black or brown, terete. 



3. Leaves pinnatifid, the apex caudate, the segments lanceolate, sessile, vari- 



able in size, more or less auricl'ed at base; on a rocky, wooded hillside 

 along the Mississippi River near McClure, Alexander Co., E. J. Palmer 

 in 1919. [Asplenmm platyneuron X Camptosorm rhizophyllus; X 



Asplenosorus ebenoides (R. R. Scott) Wherry] Scott's Spleenwort 



X -^- (^bcnoides R. R. Scott 



3. Leaves pinnate, with 15-40 pairs of leaflets. 



4. Leaflets auriculate on upper side near base, serrate; rocky woods, not 

 common. Ebony Spleenwort A. platyneuron (L.) Oakes 



4. Leaflets crenate, oval, obtuse, not auriculate; sandstone cliffs, s. III., rare. 

 Maidenhair Spleenwort A. trichomanes L. 



12. Athyrium Roth 



A. angustum (Willd.) Presl. Lady Fern. Woods, local. \_A. fltx-jcmma 

 ex p. of Am. auth., not L.] 



13. DiPLAZIUM Sw. 

 {Aspleuiiim ex p. of auth.) 



1. Pinnae entire or crenulate, the veins running into the sinuses; moist woods, 



common. [A. anguftifolium Michx.] Glade Fern 



D. pycnocarpon (Spreng.) Broun 



1. Pinnae deeply pinnatifid, the veins or veinlets running into the teeth; woods, 

 not infrequent. Silvery Spleenwort D. acrostichoides {Sw) Butters 



