20. 
5. Indusium borne beneath the sorus, surrounding its 
base as a saucer-shaped structure. 
6. Fertile and sterile fronds similar, not rigid. 
Expected (Woodsia, Dennstaedtia). 
6. Fertile and sterile fronds very dissimilar, stiff, 
the sterile much larger, the fertile erect and rigid. 
7. Fronds forming tall vase-like clumps, the sterile 
and fertile simply pinnate. Expected (Pteretis). 
7. Fronds solitary or scattered, the sterile 
coarsely pinnatifid, the fertile bi- 
PANNA’ ChcKeel eke siete eerste) ciclcislie elec) ee lels wieleersieleiaieieiere a ONOGLea 
5. Indusium spreading above or outside the sorus. 
8. Indusium attached at center, orbicular to reniforn. 
9. Indusium shield-shaped, without a sinus...... Polystichum 
9. Indusium reniform or with deep sinus......... Dryopteris 
8. Indusium attached at margin, linear or oblong 
to crescent-shaped. (Also, sori parallel to 
oblique lateral veins). 
10. Fronds deciduous, pinnate to tripinnate; 
stipes flat, angled or furrowed............. Athyrium 
10. Fronds evergreen, pinnate (in species 
collected); stipes slender, nearly terete... Asplenium 
Athyrium 
Fronds bi- to tripinnate; sori roundish or reniform; 
indusium crescent-sShaped....ecescsecereccesccceceeseees A. filix-femina 
Fronds simply pinnate or deeply bipinnatifids; sori 
straight or nearly so. Expected (A. pycnocarpon). 
A. filix-femina 
Rhizome compact, covered with persistent old stipe- 
bases; frond widest near middle; indusia toothed, if 
ciliate the hairs not gland-tipped. (Also, fertile 
fronds more leathery and contracted than the sterile; 
MACUGEMSOG CONF UEMIt) se cteerehens ei ckeheletelrelerss chereierelersietelsleleretaeie Vale much auxeel 
Rhizome horizontally creeping, with few or no stipe- 
bases; frond widest toward base; indusia ciliate, the 
Ci TaneUand tipped. «ac sic ecleicis sie/¢ el Sieeieie civic esleisisleseieivie. Vals asplentoldes 
