Jeff Davis and Presidio cos. in the Trans-Pecos, reported from N. M. (Sierra Co.); 

 from Fla. w. to Tex., N.M. (?) and Okla., n. to N. C, O. and Alas.; also the W. I. 

 and Mex. to Patagonia. 



Fam. 10. Polypodiaceae S. F. Gray True Fern Family 



Usually large terrestrial or epiphytic plants of diverse habits with short or 

 elongate creeping to suberect rhizomes; fronds clustered or remote, pendent to 

 erect-spreading, commonly stalked, occasionally dimorphic; blades simple to 

 much decompounded and variously dissected, with the veins simple to mostly 

 forked, free or united and forming areoles with or without included veinlets; 

 sporangia long-stalked, provided with an incomplete vertical annulus and open- 

 ing transversely, borne either upon the veins on the lower surface or near the 

 margins of ordinary leaf blades in lines or clusters (sori), occasionally borne on 

 wholly fertile fronds or on partially sterile blades; sori naked or covered by a 

 membrane (indusium) that develops from either the vein or modified leaf-margin; 

 prothallia green. 



This family, that includes about 50 genera and several thousand species, is by 

 far the largest family of ferns in that it includes more than two thirds of the 

 living ferns. They are found throughout the world from arctic to tropical regions 

 in dense rain forests to desert areas. 



1. Blades simple, pinnatifid or once-pinnate; pinnae or primary divisions entire, 

 toothed or pinnatifid (2) 



1. Blades twice-pinnate or more dissected (7) 



2(1). Primary divisions or pinnae with the margins entire, undulate, irregularly 

 toothed or incised, never distinctly pinnatifid (3) 



2. Primary divisions or pinnae distinctly pinnatifid (4) 



3(2). Primary segments with entire to undulate margins; sterile blade with the 

 pinnae commonly opposite or essentially so; sporophylls with the 

 divisions tightly rolled together, beadlike 2. Onoclea 



3. Primary segments with serrulate margins; sterile blades with the pinnae com- 



monly alternate; sporophylls with the divisions narrowly Hnear 



4. Lorinseria 



4(2). Sori orbicular to reniform-orbicular (5) 



4. Sori linear to elliptic, never orbicular (6) 



5(4). Acicular unicellular hairs present on the costae above; segments of the 

 fronds ciliate; stipe bundles 2, these united below the base of the 

 blade; rhizome scales ciliate (sometimes sparingly so); rhizomes 

 slender, mostly creeping; fronds membranous, mostly deciduous; 

 veins reaching the margin 6. Thelypteris 



5. Acicular hairs absent on the costae above; segments of the fronds not ciliate; 



stipe bundles 3 to 7, free to above the base of the blade; rhizome 

 scales not ciliate, sometimes toothed; rhizomes massive, short- 

 creeping to erect; fronds herbaceous to coriaceous, sometimes ever- 

 green; veins ending short of the margin in elongate hydathodes 



7. Dryopteris 



6(4). Sori parallel to and contiguous to the midrib of the leaf segments on 

 specialized veins 3. Woodwardia 



6. Sori borne obliquely to and away from the midrib of the leaf segments on 



ordinary veins 5. Athyrium 



7(1). Sori borne on the under surface of the recurved portion of the ultimate 

 segments; blades with only the apical margin of the ultimate seg- 

 ments recurved 1. Adiantum 



61 



