14 POLYPODIACEAE 



15. Asplenium acrostichoides Sw. Eootstock sinuous. Petioles 2-3 dm. long r 

 straw-colored, somewhat chaffy below at least when young ; leaf-blades lanceolate in out- 

 line, 3-9 dm. long, acute or acuminate at the apex, narrowed to the base, pinnate-pinnatifid ; 

 leaflets linear-lanceolate, sessile, acuminate, deeply pinnatitid into numerous oblong obtuse 

 or subacnte, slightly crenate segments : sori crowded, slightly curved, or straight, the lower 

 ones often double : indusium light-colored and somewhat shining when young. 



In rich moist woods, Nova Scotia to Minnesota, south to Georgia and Louisiana. Also in Asia. 



16. Asplenium Filix-fofemina (L. ) Bernh. Kootstock rather slender for the size of 

 the plant. Petioles tufted, 0.5-2.5 dm. long, straw-colored, brownish or reddish ; leaf- 

 blades broadly oblong-ovate or oblong-lanceolate, acuminate at the apex, 3-9 dm. long, 2- 

 pinnate ; leaflets lanceolate, acuminate, short-stalked or the upper ones sessile, 1-2 dm. 

 long, the ultimate divisions oblong-lanceolate, incised or serrate, their lobes or teeth often 

 again toothed, those toward the ends of the leaflets confluent by a very narrow margin to- 

 the secondary rachis : sori short, the indusia straight or variously curved, sometimes horse- 

 shoe-shaped. 



In wet woods and thickets, Nova Scotia to Alaska, south to Florida, Louisiana and Arizona. Also- 

 in Europe and Asia. Very variable. 



17. PHYLLITIS Ludwig. 



Large ferns with oblong or strap-shaped mostly entire leaf-blades. Sori linear, elon- 

 gated, almost at right angles to the midrib and contiguous in pairs, one on the upper side 

 of a veinlet, the other on the lower side of the next contiguous veinlet, thus appearing to 

 have a double indusium opening longitudinally along its middle. [Scolopendrium Adans. ] 



1. Phyllitis Scolope'ndrium (L. ) Newman. Rootstocks short, chaffy with light 

 brown scales. Petioles 5-15 cm. long, fibrillose-chaffy below or sometimes up to the top ; 

 leaf -blades entire, bright green, firm, 2-4.5 dm. long, cordate at the base, pairs of sori dis- 

 tinct, 4-15 mm. long, conspicuous : veins free, usually once forked near the midrib. 

 [Scolopendrium vulgare J. E. Smith.] 



On shaded limestone cliffs, New Brunswick to Ontario and New York, south to Tennessee. Also- 

 in Europe, Asia and Africa. HART'S TONGUE. 



18. CAMFTOSORUS Link. 



Slender plants, with tapering simple entire or undulate leaf-blades. Sori linear or ob- 

 long, several times longer than broad, irregularly scattered on either side of the reticulate 

 veins or sometimes crossing them, partly parallel to the midrib and partly oblique to it, the 

 outer ones more or less approximate in pairs. Jndusium membranous. 



1. Camptoaorus rhizophyllus (L.) Link. Rootstock short, chaffy. Petioles light 

 green, 2.5-15 cm. long, tufted, spreading ; leaf -blades rather thin, lanceolate, simple, long- 

 acuminate at the apex, cordate, hastate or rarely narrowed at the base, 10-25 cm. long, 

 sometimes with a more or less elongated pair of basal auricles ; tip of the leaf and sometimes 

 the tip of one or both of the basal auricles rooting and forming a new plant by the ultimate 

 withering away of its tissue : sori usually numerous, irregularly scattered. 



On rocks, preferring limestone, Quebec to Ontario and Minnesota, south to Georgia and Kansas. 

 WALKING LEAF. WALKING FERN. 



19. LORINSERIA Presl. 



Rather coarse ferns of swamps, with dimorphous leaves and rather large linear sori 

 sunk in cavities in the leaf and arranged in chain-like rows. Indusia rather leathery, fixed 

 by their outer margins and covering the cavity like a lid. Veins forming copious areolae. 



1. Lorinseria areolata (L. ) Presl. Rootstock slender, chaffy. Leaves of two kinds, 

 the fertile taller than the sterile and their blades borne on longer petioles, 3-6 dm. high, 

 their segments much contracted, narrowly linear, 7-12.5 cm. long, 4-6 mm. wide, distant, 

 their bases connected by a very narrow wing along the rachis or quite distinct ; sterile leaf- 

 blades deltoid-ovate, membranous, broadest at the base, or sometimes with one or two -small 

 segments below, acuminate, the segments lanceolate or oblong-lanceolate, minutely serru- 

 late, sometimes undulate, their bases connected by a rather broad rachis-wing. [ Wood- 

 wardia angustifolm J. E. Smith. ] 



In swamps or wet woods, Maine and Michigan to Florida, Louisiana and Arkansas. 



20. ONOCLEA L. 



Ferns with elongated horizontal rootstocks. Leaves growing separately. Fertile leaf- 

 blades closely rolled up into berry-like segments, and entirely unlike the broad pinnatifid 



