PTERIDOPHYTA. 13 



straw-colored, brownish or reddish; leaves broadly oblong-ovate or oblong-lanceo- 

 late, acuminate at the apex, 3-9 dm. long, bipinnate; pinnae lanceolate, acuminate, 

 short-stalked or the upper ones sessile, 1-2 dm. long; pinnules oblong -lanceolate, 

 incised or serrate, their lobes or teeth often again toothed, those toward the ends oi 

 the pinnae confluent by a very narrow margin to the secondary rachis ; sori short, 

 the indusia straight or variously curved, sometimes horseshoe-shaped. In woods, 

 thickets, and by walls and fences, N. S. to Alaska, south to Fla., La., and Ariz. 

 Also in Europe and Asia. 



10. PHYLLITIS Hill, 1756. [Scolopendrium Adans. 1763.] 



Large ferns with oblong or strap-shaped mostly entire leaves, and linear 

 elongated sori which are 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. Five species, mainly of temperate regions. Only the following 

 is known to occur in N. Am. [Greek name of the Harts-tongue.] 



i. Phyllitis Scolopendrium (L.) Newman. HARTS-TONGUE. (I. F. f. 44.) 

 Rootstock short, chaffy with light brown scales. Stipes 5-15 cm. long, fibrillose- 

 chaffy below or sometimes up to the base of the leaf ; leaves entire, bright green, 

 firm, 2-4.5 dm. l n g> 2 -5-6 cm. wide, cordate at the base, the margins entire or 

 undulate, the lower surface of the midrib sometimes chaffy; pairs of sori distinct, 

 4-15 mm. long; conspicuous on the lower surface, the sporanges dark brown at 

 maturity; veins free, usually once forked near the midrib. On shaded cliffs of the 

 corniferous limestone, Chittenango Falls and Jamesville, N. Y. ; near South Pitts- 

 burg, Tenn. ; Owen Sound, Ont., N. B. and Mex. Widely distributed in Europe, 

 Asia and Africa. 



11. CAMPTOSORUS Link. 



Slender ferns with tapering simple entire or undulate leaves, bearing linear or 

 oblong sori 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. Indusium 

 membranous. [Greek, referring to the bent or curved sori. ] Two species. 



i. Camptosorus rhizophyllus (L.) Link. WALKING-FERN. (I. F. f. 45.) 

 Rootstock short, usually creeping, chaffy. Stipes light green, 2.5-15 cm. long, 

 tufted, spreading ; leaves 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, but commonly two or sometimes as many as four 

 plants are found connected; sori usually numerous, irregularly scattered on the 

 lower surface. On rocks, preferring limestone, P. Q. to Ont. and Minn., south to 

 N. Car. and Kan. 



12. POLYSTICHUM Roth. 



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 continuous, not 

 jointed with the rootstock. Veins free. [Greek, signifying many rows, without 

 obvious application. ] Some 45 species of wide distribution. 



Leaves once pinnate. 



Stipes short ; lower pinnas much reduced. I. P. Lonchitis. 



Stipes longer ; lower pinnae usually little reduced. 2. P. acrostichoides. 



Leaves 2-pinnate. 3. P. Braunii. 



i. Polystichum Lonchitis (L.) Roth. HOLLY-FERN. (I. F. f. 26.) Rootstock 

 short, stout, densely chaffy. Stipes 2.5-12.5 cm. long, bearing large dark brown 

 scales with some smaller ones ; leaves rigid, evergreen, narrowly lanceolate in 

 outline, once pinnate ; pinnae broadly lanceolate-falcate, 2.5-5 cm - l n g> acute or 

 acuminate at the apex, strongly auricled on the upper side at the base and obliquely 

 truncate on the lower, densely spinulose-dentate, the lowest commonly triangular 



