acuminate, pinnate-pinnatifid to rarely bipinnate, slightly pubescent (especially 

 the rachises), 9-20 cm. wide, membranous to herbaceous; pinnae numerous, linear- 

 lanceolate to lanceolate, somewhat acuminate, sessile or nearly so, deeply pinnati- 

 fid to rarely pinnate, to 3 cm. wide, the midrib beneath mostly with broad brown 

 or tawny scales at the base of the ultimate segments; pinnules or ultimate segments 

 mostly linear-oblong, numerous and closely set, entire or with minutely undulate 

 margins, obtuse or appearing to be acute because of the revolute margins, to 1.5 

 cm. long, with all the veins (including those of the fertile segments) commonly 

 once- or twice-forked; sori medial, numerous, sometimes confluent; indusia small, 

 glabrous. 



In open sandy bogs, swamps and meadows, or in open low woodlands, seepage 

 about lakes and ponds, and along streams, rare in several cos. in the e. Tex. 

 Timber Belt and in Jefferson Co. in the Coastal Prairies and Waller and Colorado 

 cos. in the Post Oak Prairies; from Fla. to e. Tex., n. to (?) Pa. 



4. Thelypteris dentata (Forsk.) E. St. John. Downy shield fern. Fig. 18. 



Fronds clustered, erect-ascending from a thick rhizome, to 12 dm. tall; stipe 

 and rachis purplish; blades ovate-oblong to lanceolate, to 8 dm. long and 28 cm. 

 wide; pinnate-pinnatifid, with usually more than 2 pair of greatly reduced pinnae 

 at the base, costae below with predominantly 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. Dryopteris dentata (Forsk.) C. Chr. 



On rocky wooded slopes, on hummocks in swamps, and along wooded streams 

 at low elev., rare in the Tex. Timber Belt; from Fla. to Tex., in part escaped 

 from cult.; also from Mex. to Arg., the W.I., Asia and Afr. 



5. Thelypteris quadrangularis (Fee) Schelpe var. versicolor (R. St. John) A. R. 



Smith. 



Fronds erect, arching, mostly 3-10 dm. tall; rhizomes short-creeping to suberect, 

 obscured by the persistent leaf bases; stipes 1.5-5 mm. in diameter, pubescent, 

 stramineous above, sometimes darkened at the base, nearly as long as the blades, 

 with lanceolate shining dark-brown to castaneous pubescent scales at the base; 

 blades elliptic-lanceolate, usually with 1 or 2 pair(s) of somewhat reduced 

 pinnae below, occasionally the pinnae very little reduced below, auricled or not, 

 1-3 dm. wide, herbaceous; pinnae numerous, linear-lanceolate, sessile, pinnatifid 

 two thirds to four fifths of their width, to 2 cm. wide; pinnules linear-oblong, 

 somewhat oblique, rounded at the apex, entire; the veins simple, mostly 6 to 9 

 pairs per segment, the basal pair from adjacent segments united below the sinus 

 with an excurrent veinlet less than 1 mm. long to the sinus or the lower pair of 

 veins not uniting at all but approaching each other below the sinus and turning 

 abruptly toward the sinus; costae, costules, veins and leaf tissue pubescent above 

 and below, the hairs often stout and to 0.8 mm. long; stipitate yellow glands 

 often present on both surfaces of the blade; sori medial, numerous or sometimes 

 confined to the basal pair of veins, discrete; indusia persistent, pubescent; sporan- 

 gial stalks with minute glands. T. versicolor R. St. John. 



On the edge of sandy creeks, boggy or swampy areas and wooded slopes in e. 

 Tex.; S.C. to e. Tex.; also Cuba; other vars. in Latin Am. and Afr. 



6. Thelypteris ovata R. St. John var. Lindheimeri (C.Chr.) A. R. Smith 



Fronds erect, arching, mostly 5-14 dm. tall; rhizomes widely creeping, brownish, 

 3-6 mm. in diameter; stipes 2-6 mm. in diameter, arising from the rhizome in a 

 more or less bilinear series 1-4 cm. apart, glabrous or nearly so, stramineous 

 above, darkened at the base, about as long as the blades, paleate at the base, the 

 light-brown scales narrowly lanceolate and short-ciliate at the margin; blades 

 deltoid-lanceolate, mostly 30-75 cm. long, 15-50 cm. wide, pinnate-pinnatifid, 



74 



