1. Fertile segments not contracted; fertile fronds with most or all of the pinnae 



fertile, erect, 2 to 3 times as long as the spreading sterile fronds 



1. D. cristata. 



1. Fertile segments sharply contracted to about one half the width of the sterile 

 segments; fertile fronds with fertile pinnae only in upper half, 2 

 times or less the length of the sterile fronds 2. D. ludoviciana. 



1. Dryopteris cristata (L.) Gray. Crested shield fern. Fig. 21. 



Fronds inconspicuously dimorphic, clustered on a thick rhizome, glabrous on 

 upper surface, sparsely scaly on lower surface, to 12 dm. tall; sterile fronds broad 

 and spreading, usually evergreen; fertile fronds narrow and erect; blades (of both 

 types of fronds) subcoriaceous, linear-oblong to lanceolate or narrowly elliptic- 

 lanceolate, to 8 dm. long and 15 cm. wide, pinnate-pinnatifid to nearly bipinnate; 

 ultimate segments mostly toothed, often subspinulose, glabrous, not ciliate, some- 

 times capitate-glandular, sparingly or densely scaly; veins free, simple or mostly 

 forked, ending short of the margin in elongate hydathodes; sori dorsal on the 

 veins. 



In marshes, bogs, swamps, thickets and meadows, and on springy wooded 

 slopes, at low elevations, if extant in our region, only in the n.e. corner of the 

 Tex. Timber Belt (Bowie Co., "margin of sandy bog near Texarkana," October 

 27, 1925, E. J. Palmer 29404, p. p.); from Nfld. to Ida., s. to e. Va., N.C., s.e. 

 Ark., n.-cen. La. and n.e. Tex. 



6. Dryopteris ludoviciana (Kunze) Small. Fig. 21. 



Rhizomes horizontal, with cinnamon-colored scales; fronds arising in a short 

 row behind a cluster of apical buds; blades oblong, 5-10 dm. long, 1.5-3 dm. 

 wide, pinnate-pinnatifid to almost bipinnate; pinnae lanceolate, about 4 times as 

 long as wide, the basal pinnae triangular and one half to less as long as longest 

 pinnae, their ultimate segments more or less dimorphic and serrate; fertile pinnae 

 with more widely spaced segments that are constricted to about one half the width 

 of the sterile segments; sori inframedial; indusia nonglandular. 



In swamps, in seepage at base of bluffs, low wet woods and on stream banks, in 

 s.e. Tex (Hardin and Tyler Cos.); from e. N.C. s. to Fla. and w. to s.e. Tex. 



Fam. 11. Parkeriaceae Hook. Floating Fern Family 



Aquatic or semiaquatic plants with roots on the stipes; stems creeping, sparsely 

 scaly, reduced; fronds alternate, successive, viviparous, fleshy-herbaceous, di- 

 morphic, reticulate-veined, floating or emergent; sporophylls erect, taller and 

 more finely divided than the sterile fronds, the linear ultimate segments with the 

 margins evenly and narrowly revolute; sporangia solitary. 



Only one genus. 



1. Ceratopteris Brongn. 



Characteristics of the family. Three species, mostly in the tropics and sub- 

 tropics of both hemispheres; edible aquatic plants. 



1. Ceratopteris thalictroides (L.) Brongn. Fig. 22. 



Fronds erect, strict, to 75 cm. long, usually much smaller; stipes 4—27 cm. long; 

 lamina of sterile frond narrowly deltoid to oblong, to 28 cm. long and 13 cm. 

 wide, 1- or 2-pinnate or -pinnatifid with the pinnae ovate-lanceolate; segments 

 Hnear-lanceolate to oblong, acute, to 25 mm. long and 5 mm. wide; sporophylls 

 taller than the sterile fronds, the oblong lamina 2- to 5-pinnately divided with the 

 pinnae and smaller divisions distant; ultimate segments flagelliform, 1-5 cm. long, 

 the margins narrowly revolute to cover 1 or 2 rows of areolae and sporangia. 



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