The Fern Lover's Companion 107 



THE SHIELD FERNS 



The (.'hristmas axd Holly Ferxs 

 Poli/.slichinn 



These have heeii grouped with the wood ferns, 1)ut are 

 now usuahy ])hxeed under the genus Polj/.siichum, wliieh 

 has the sori round and coxered with a circular indusium 

 fixed to the frond by its depressed center. The wood 

 ferns, on the other hand, ha\e a kidney -slia])ed indusium 

 attaclied to the fronds by tlie sinus, (l^ilf/.tlichum is tlie 

 (Ireek for many rows, the sori of some species being in 

 many ranks.) 



(1) The Christmas Fern 

 Polijst ich inn ac ro.s/ ich o iilcs. ^i sp idiiim (ici-iikI ich b id en 



Stipes clotlied with jjale, brown scales. Frond rigid 

 and evergreen, one to two feet long, lanceolate, pinnate. 

 Pinnae hnear-lanceolate, scythe-shaped, aiu'icled on the 

 upper side, and with bristly teeth; fertile i)inna> con- 

 tracted toward the top, licaring two rows of sori, which 

 .soon become confluent and cover the entire surface. 

 Indusium orljicular, fixed by its depressed center. 



F. indsiiui is a form in which the jjimiic are much 

 incised. 



F. crispum has the edges of its pinn;c crisped and 

 rufSed. 



