424 



POLYPODIACEAE. 



10. POLYST1CHUM Eoth. 



'Coarse pinnate or bipinnate ferns growing from an erect rootstock, with 

 round sori usually borne on the backs of the veins, the sterile and fertile leaves 

 similar in outline. Indusium superior, centrally peltate, orbicular. Stipe con- 

 tinuous, not jointed with the rootstock. Veins free. [Greek, signifying many 

 rows, without obvious application.] Some 100 species of wide distribution. 

 Type species: Polystichum Lonchitis (L.) Eoth. 



1. Polystichum adiantiforme (Fors- 

 ter) J. Smith. TEN DAY FERN. DEVON- 

 SHIRE MARSH FERN. (Fig. 462.) Root- 

 stock stout, creeping; leaves several, 1- 

 4 high, subcoriaceous, 2-3-pinnate. 

 Lower pinnae the largest, sometimes 1 

 long, 3'-4' wide ; pinnules ovate-lanceo- 

 late in outline, acuminate; ultimate seg- 

 ments or lobes oblong or oblong-lanceo- 

 late, acutish serrate; rachis smooth and 

 somewhat shining; stipes scaly at the 

 base; sori nearly 1" broad, mostly in 2 

 rows between the margin and the mid- 

 vein of the segments. [Polypodium 

 adiantiforme Forster; Aspidium capense 

 Willd. ; Dryopteris capensis Gilbert ; 

 Aspidium coriaceum of Hemsley and of 

 Verrill.] 



Local in Devonshire Marsh, and among 

 shaded rocks between Harrington Sound and 

 Castle Harbor. Native. West Indies, South 

 America, Polynesia, Africa. Figure 462 

 shows a single pinna. 



Polystichum aculeatum. (L.) Schott is recorded by Hemsley as found at 

 caves by Lefroy, and also mentioned as Bermudan by Eein, by Verrill, and by 

 Jones, but it has not been seen here recently. It may have been in cultivation, 

 or may have been mistaken for P. adiantiforme. [Dryopteris aculeata Kuntze; 

 Aspidium aculeatum Sw.] 



11. DRYOPTERIS Adans. 



Ferns with 2-3-pinnate or pinnatifid leaves and round sori usually borne 

 on the backs of the veins, the fertile and sterile leaves similar in outline. 

 Indusium flattish, cordate, reniform, superior, fixed by its sinus. Stipe con- 

 tinuous, not jointed with the rootstock. Veins free or anastomosing. [Greek, 

 signifying oak-fern, in allusion to the forest habitat of most species.] Species 

 several hundred, of wide distribution. Type species: Polypodium Filix-mas L. 



Leaves once pinnate. 

 Pinnae all sessile. 



Veinlets not forked. 

 Veinlets forked. 



At least the lower pinnae short-stalked. 

 Leaves bipinnate or tripinnate. 



1. D. nor mails. 



2. D. Thelypteris. 



3. D. bermudiana. 



4. D. spcluncae. 



