PTERIDOPHYTA. 5 



cleft into oblong obtuse segments, some of the leaves contracted in the middle and 

 bearing 2-5 pairs of sporophylls with dense, cylindric divisions which are green- 

 ish at first, afterwards dark brown, finally withering ; leaves clothed with (omen- 

 tum when young, glabrous when mature, the fertile ones taller than the sterile, and 

 finally widely recurving. In moist places. Newf. to Minn., N. C. and Mo. Also in 

 India. May-July. 



Family 3. HYMENOPHYLLACEAE Gaud. 



Membranous, mostly small ferns with filiform or slender creeping root- 

 stocks. Leaves usually much divided. Sporanges sessile on a filiform, 

 usually elongated receptacle, surrounded by a transverse ring which opens 

 vertically. Several genera, comprising some 200 species, very abundant 

 in tropical regions. 



1. tricho'manes l. 



Delicate filmy ferns, the leaves usually much divided. Sporanges flattened, 

 surrounded by a broad entire transverse ring opening vertically, sessile on the 

 lower part of the slender filiform receptacle. Receptacle surrounded by a tubular 

 or funnel-shaped indusium which is truncate or slightly 2-lipped. [Greek, in al- 

 lusion to the thin hair-like segments of some species. ] About 100 species, mostly 

 of tropical regions. 



1. Trichomanes Boschianum Sturm. Bristle Fern. (I. F. f. 11.) Rootstock 

 filiform, wiry, tomentose, creeping. Stipes (petioles] ascending. 2.5-7.5 cm. long, 

 naked or nearly so; leaves 5-20 cm. long, 1.5-3.3 cm. wide, membranaceous, lanceo- 

 late or ovate-lanceolate, 2-3-pinnatifid ; pinnse ovate, obtuse, the upper side of the 

 cuneate base parallel with or appressed to the narrowly winged rachis ; segments 

 toothed or cut into linear divisions ; indusia terminal on short lobes, 1-4 on a pin- 

 nule, the mouth slightly 2-lipped, receptacle more or less exserted. On wet rocks. 

 Ky. to Fla. and Ala. Has been confused with the West Indian T. radicans Sw. 



Family 4. SCHIZAEACEAE Reichenb. 



Ferns of various habit, with simple or pinnate leaves. Sporanges borne 

 in spikes or panicles, ovoid, sessile, provided with an apical ring, opening 

 vertically by a longitudinal slit. Several genera and about 100 species, 

 mainly tropical. 



Sporanges in close 2-ranked spikes ; leaves filiform or linear. 1. Schizaea. 



Sporanges in ample panicles ; pinnules palmate. 2. Lygodium. 



1. SCHIZAEA J. E. Smith. 



Small slender ferns with filiform or linear leaves, the fertile distinct from the 

 sterile. Sporanges sessile in close distichous spikes along the single vein of the 

 narrow divisions of the sporophylls, provided with a complete apical ring. [Greek, 

 in allusion to the cleft leaves of some species.] A genus of 19 species, of wide dis- 

 tribution, mostly tropical. 



1. Schizaea pusilla Pursh. Curly-grass. (I. F. f. 12.) Sterile leaves 

 linear, slender and tortuous. Sporophylls longer, 7-12 cm. high, the fertile portion 

 terminal, consisting of about 5 pairs of crowded pinnae, forming a distichous spike; 

 sporanges ovoid or pyriform. sessile in two rows along the single vein of the narrow 

 incurved linear divisions of the fertile leaf, partially concealed by its incurved 

 margins, which are hooded at the apex and ciliate ; ring apical, the sporanges 

 opening by a vertical slit. In wet soil, pine-barrens of N. J. and in N. S. and 

 Newf. Rare and local. Aug.- Sept. 



2. LYGODIUM Sw. 



Twining or climbing ferns, the lower divisions sterile, variously stalked and 

 lobed, the fertile terminal, panicled. Sporanges ovoid, solitary or in twos in the 

 axils of imbricated scale-like indusia, provided with an apical ring, opening verti- 



