46 POLYPODIACEAE Dryopteris 



Fronds longer than wide, dark green, more coarsely pubescent beneath and with 



prominent brown scales along the rachis; veins of the pinnules on the lowest 



pair of pinnae simple or once forked. (See excluded species no. 3, p. 1019.) 



D. Phegopteris. 



Indusia present; blades of fronds not triangular or ternate. 



Rootstocks creeping; veins simple or once forked; fronds lanceolate in outline. 

 Lowest pinnae gradually decreasing in size toward the base; the lowest usually 



less than 1 cm long; veins simple; indusia glandular 2. D. noveboracensis. 



Lowest pinnae scarcely smaller than the middle ones. 



Veins of sterile fronds generally forked; sori crowded; indusia without glands. 



3. D. Thelypteris var. pubescens. 



Veins simple; sori distant; indusia glandular. (See excluded species no. 4, 



p. 1020.) D' simulata. 



Rootstocks short, suberect; fronds cespitose, never pubescent, their veins, at least 

 the lowest, more than once forked. 



Sori marginal 4. D. marginalis. 



Sori not marginal. 



Pinnae widest above the base; basal scales of stipe dark chestnut color; sori 

 mostly 3-7 pairs; the largest fern of the genus (in Indiana) . .5. D. Goldiana. 

 Pinnae widest at the base; basal scales of stipe not so dark colored as the 

 preceding. 

 Surface of indusium glabrous. 

 Fronds bipinnatifid or pinnate. 



Basal scales of stipe lance-linear, caudate-attenuate; segments with 

 parallel sides, serrate at the rounded apex and obscurely so, if at 

 all, on the sides, the teeth rarely somewhat spinulose; sori usually 

 on the lower half of the segment. (See excluded species no. 5, 



p. 1020.) D. Filix-mas. 



Basal scales of stipe wider; teeth of segments more or less spinulose; 



sori not restricted to the lower half of the segment. 



Fronds linear-oblong or lanceolate in outline; pinnae 5-8 cm long, 



triangular-oblong or the lowest pair somewhat triangular-ovate, 



usually the lower half of the frond conspicuously decreasing in 



size toward the base 6. D. eristata. 



Fronds wider; pinnae 8-15 cm long, oblong-lanceolate, the lower half 



of the frond not decreasing in size toward the base 



6a. D. eristata var. Clintoniana. 



Fronds bipinnate, tripinnate, or tripinnatifid, segments with spinulose teeth. 



Basal inferior and superior pinnules of the lowermost pinnae subopposite, 



rarely more than 4 mm apart; the inferior 1-6 cm long, if more, then 



twice as long as the superior; pinnules of the middle pinnae often 



only toothed; pinnules pinnatifid or pinnate 7. D. spinulosa. 



Basal inferior and superior pinnules of the lowest pinnae remote, 0.5-2 

 cm wider apart; the inferior 3-10 cm long, 2-4 times as long as the 

 superior; pinnules pinnatifid or pinnate. (See excluded species no. 7, 



p. 1020.) D. spinulosa var. americami. 



Surface of indusium glandular. 



Frond commonly minutely glandular especially on the rachis and rachillae, 



tripinnatifid or sometimes tripinnate; pinnae slightly ascending to 



divergent, the basal inferior pinnule shorter than to rarely exceeding 



the second inferior one ; scales of stipe usually dark brown at base. 



Mature indusium 0.8-1.4 mm wide; pinnae gradually tapering to apex. 



7a. D. spinulosa var. fructuosa. 



Mature indusium 0.5-0.8 mm wide; pinnae usually narrowed rather 



abruptly to prolonged lance-linear tips 



7b. D. spinulosa var. intermedia. 



Frond not minutely glandular but more or less chaffy, bipinnate or tripin- 

 natifid S. D. Boottii. 



