496 



FILICES. 



ASPIDIUM. 



3. Aspidium cristatum, Swartz. Crested Shield-fern. 



Frond pinnate, lanceolate, somewhat rigid ; pinnae oblong or triangular-ovate, deeply pin- 

 natifid, somewhat cordate ; segments oblong, obtuse, doubly serrate ; sori near the midrib, 

 large ; involucre orbicular-reniform ; stipe nearly naked. — Swartz. syn. Fil. ; Willd. sp. 

 5. p. 252 ; Pursh, fl. 2. p. 661 ; Engl. bot. t. 2125 ; Beck, bot. p. 449. A. cristatum, /3. 

 Lancastriense, Torr. compend. p. 577. A. Lancastriense, Spreng. ; Bigel. fl. Bost. p. 391 ; 

 Beck, I. c. ; Darlingt. fl. Cest. p. bll ; Hook. fl. Bor.-Am. 2. p. 261. Lastrea cristata, 

 Presl. 



Stipe rather stout, varying from tawny to brown. Frond 1^-2 feet long and 3-5 inches 

 wide, somewhat uniform in its breadth, except towards the summit, bright green : pinnae 

 opposite or alternate ; the lowest ones broad at the base : segments 6-8 lines long, sharply 

 (and the lower ones doubly) serrate. Sori rather large, 10 - 14 on each segment, situated as 

 in the preceding species, finally somewhat confluent. Involucre smooth, becoming funnel- 

 form and stipitate by the growth of the capsules around it. 



Moist woods and borders of swamps : rare. Fr. July. I entirely agree with Hooker in 

 regarding this fern as identical with the European A. cristatum. 



4. Aspidium dilatatum, Swartz. Dilated Shield-fern. 



Frond bipinnate ; the pinnules deeply and incisely pinnatifid ; segments or laciniae mucro- 

 nate-serrate ; sori minute, distinct, situated about the middle of the pinnules, in a double 

 row ; involucre orbicular-reniform ; slipe chaffy. — Swartz, I. c. ; Willd. sp. 5. p. 263 ; 

 Pursh, fl. 2. p. 663 ; Torr. compend. p. 382 ; Beck, bot. p. 450 ; Darlingt. fl. Cest. p. 

 578. A. intermedium, Muhl. in Willd. sp. I. c. ; Pursh, I. c. A. spinulosum, Willd. I. c. ? 

 Pursh, I. c. Nephrodium cristatum, Michx. fl. 2. p. 269. Lastrea dilatata, J. Sm. 



Slipe 6-10 inches long, rather slender, pale brown, more or less chaffy with thin brown 

 scales. Frond 1-1^ foot long, ovate-lanceoiate in outline, thin, light green : pinnae numerous, 

 mostly opposite : pinnules cut into small ovate or oblong segments or laciniae, which again 

 are incisely serrate ; the serratures acuminate and mucronate at the tip. Sori scarcely the 

 size of the smallest pin's head, situated about the middle of the base of the laciniae. Involucre 

 light brown, umbilicate in the centre, smooth or slightly glandular-pubescent. 



Shady woods and thickets : frequent. Fr. July. Hooker refers this species to A. spinu- 

 losum of Willdenow, to which he also adds A. dumetorum, Sm., and Nephrodium expansum, 

 Presl. 



5. Aspidium Thelypteris, Swartz. Meadow Shield-fern. Lady-fern. 



Frond pinnate ; pinnae linear-lanceolate, sessile, gradually diminishing in length from below 

 upward, deeply pinnatifid ; segments ovate-oblong, rather acute, the margin slightly crenulate, 



