lobules often again toothed; sori short, 3 to 10 pairs in each segment; indusia 

 mostly curved, with gland-tipped cilia. A. asplenioides (Michx.) Eat. 



In sandy bogs, moist sandy woods, swamps, wet thickets and on stream banks 

 in s.e. Okla. and in Tex. generally distributed and rather common in the Timber 

 Belt and in several n. border cos. in the Coastal Prairies, w. to Williamson Co. 

 in the Blackland Prairies; from Fla. to Tex., n. to e. Mass., Ind. and Mo. 



Var. californicum Butters. Characterized by its dark scales, indusia short ciliate 

 or merely toothed, and large spores with a distinct, wrinkled and reticulate 

 exospore. 



In habitats similar to those of var. asplenioides in N.M. (Socorro, Grant, San 

 Miquel and Rio Arriba cos.) and Ariz. (Apache, Graham, Cochise and Pima cos.); 

 Ida. and w. Wyo., s. to N.M., Ariz, and Calif. 



6. Thelypteris Schmid. 



Terrestrial plants of moist woodlands and rocky places, with stout or mostly 

 slender strong long-creeping sparsely scaly rhizomes; scales of the rhizome ciliate, 

 entire, fibrous; fronds erect-ascending, somewhat distant, deciduous; stipes stra- 

 mineous, essentially scaleless, with two bundles at the base; blades uniform, thin- 

 membranous, bipinnatifid to pinnate-pinnatifid or bipinnate-pinnatifid, pubescent 

 with acicular unicellular hairs on the costae above, rarely sparsely scaly; ultimate 

 segments usually entire or nearly so, rarely serrate or coarsely toothed, ciliate; 

 veins few, simple or once-forked, reaching the margins; sori dorsal on the veins, 

 median or supramedial; indusia small or sometimes absent, reniform, usually 

 glandular or ciliate. 



A large world-wide genus of several hundred species that attains its optimum 

 development in temperate and subtropical Asia. 



1. Ultimate segments with the margins serrate or coarsely toothed 



1, T. Torresiana. 



1. Ultimate segments with the margins entire to crenate or nearly pinnatifid, never 



serrate nor toothed ( 2 ) 



2(1). Blades strongly triangular, pinnatifid (the rachis winged throughout); 

 indusia wanting 2. T. hexagonoptera. 



2. Blades lanceolate to elliptic-lanceolate or sometimes ovate-lanceolate, pinnate; 



indusia present (3) 



3(2). Veins of ultimate segments once- or twice-forked; indusia glabrous 



3. T. palustris var. Haleana. 



3. Veins of ultimate segments simple; indusia variously pubescent (section Cyclo- 



sorus) (4) 



4(3). Basal veins of adjacent segments united below the sinus with an excurrent 

 vein leading toward the sinus; costules, veins and often lamina 

 above hairy (5) 



4. Basal veins of adjacent segments free below or connivent at the sinus; costules, 



veins and lamina above with or without hairs (6) 



5(4). Costae below with predominately short hairs which are uniform in length 

 (less than 0.2 mm. and often less than 0.1 mm. long); excurrent 

 veins mostly greater than 2 mm. long; stipe purplish; frond with 



usually more than 2 pairs of greatly reduced pinnae at the base 



4. T. dentata. 



5. Costae below with most hairs greater than 0.3 mm. long with some exceeding 



0.5 mm.; excurrent veins less than 2 mm. long; stipe stramineous; 



fronds with to 2 pairs of reduced pinnae at the base 



5. T. quadrangularis var. versicolor. 



69 



