17. POLYSTICHUTSIi Roth, 1800. 
floc genus Polystichum nominavi (ex verbts rorv 
mulium et otixos ordo) guia fructificationum puncta 
plura in ordines vel sertes ordinata plerumgque obser- 
waniur.  hoth, Fl, Germ: 3:69. 
Rootstock stout, very chaffy. Leaves pinnate, spinu- 
lose-serrate. Sori large. Indusium peltate. 
|. P. acrostichoides (L.C. Rich.) Schott. 
filix mas foltts integris aurtculatis Banister; 
Ray, Hist. 1926. 
Polypodium fronde pinnata lanceolata, folits lun- 
ulatts ctltato-serratts. Gron. F\. Virg. 123. 
Nephrodium acrostichotdes L. C. Rich.; Michx. 
22 207, 
oe acrostichotdes Sw. Syn. Fil. 44. Haton, 
Ferns N. Am. 1: 257. t. 34; in Gray Man. 689. 
Polystichum acrostichoides Schott, 1834. Gen. Fil. 
Underw. Nat. Ferns 115; in Britt. Man. 14. Clute 
Ferns 106. Waters, Ferns 244. 
Dryopterts acrostichotdes Kuntze, 1891. Revisio 
Gen. 2: 812. Underw. in Ill. Fl. 1: 14. 
CHRISTMAS FERN. 
Plant 3—6 dm. high; leaves very chaffy below ; pinnae 
2—8 cm. long, auricled on the upper side, oblong-lance- 
olate, spinulose-dentate ; upper pinnae fertile, reduced and 
at length covered by the numerous sori. 
In dry, deciduous woods. 
The form P. acr. Schweitnitztz, having toothed or in- 
cised pinnae, has been observed by /. H. Panter at 
Cabin John, Md. 
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