HYMENOPHYLLACEAE 



Sporangia ovoid or pyri- 

 form, with a complete 



apical ring. Fam. 3. SCHIZAEACEAE. 



Sporangia borne on the back 

 or margin of a leaf-blade. Fam. 4. POLYPODIACEAE. 



FAMILY 1. HYMENOPHYLLACEAE 

 FILMY-FERN FAMILY 



Delicate or dainty, mostly matted small ferns with 

 filiform or slender creeping or suberect rootstocks. 

 Leaves often numerous and crowded: blades very 

 thin, entire, erose, toothed, or usually much divided, 

 the leaf -tissue pellucid, usually consisting of a single 

 layer of cells. Sporangia sessile upon a filiform 

 usually elongate receptacle within an urceolate, cup- 

 like, or tubular, either truncate or 2-lipped marginal 

 indusium which arises at the tip of a vein; ring com- 

 plete, transverse* opening vertically. There are two 

 genera in the filmy-fern family, the following and 

 Hymenophyllum. The latter, common throughout 

 wet tropical regions, has not yet been found within 

 the United States. 



1. TEICHOMANES L. 



Plants extensively creeping, often densely matted, ter- 

 restrial or epiphytic. Leaves remote or close together 

 on the rootstock: blades entire, lobed, or pinnatifid, or 

 several times pinnately divided, or flabellate. Indusium 

 tubular or funnel-form, truncate or sometimes broadly 

 2-lipped, the sporangia mostly upon the lower portion 

 of the slender often exserted receptacle. Two species 

 occur on the adjacent Everglade Keys and another has 

 been found in northern Florida. An additional species 

 is found in Georgia, Alabama, and Mississippi. (FILMY- 

 FERN.) 



