Open main menu

An Illustrated Flora of the Northern United States, Canada and the British Possessions/Hymenophyllaceae

Family 3.   HymenophyllàceaeGaud.   in Freyc. Voy. 262.   1826.
Filmy-Fern Family.

Membranaceous, mostly tropical small ferns, with slender often filiform creeping or rarely suberect rootstocks, the leaves usually much divided, the leaf-tissue pellucid, usually of a single layer of cells. Sporanges sessile upon a filiform, usually elongate receptacle, within an urn-shaped or tubular truncate or twolipped marginal indusium, terminal upon the veins; ring complete, transverse, opening vertically.

Two genera, Hymenophyllum and the following, comprising some 450 or more species, abundant in the humid tropics and mainly epiphytic.

{{{1}}}

Blades entire, pinnatifid or lobed, or several times pinnately divided. Indusium tubular or funnel-shaped, truncate or sometimes broadly two-lipped, the sporanges sessile, mostly upon the lower portion of the slender often exserted receptacle. [Greek, in allusion to the delicate hair-like ultimate segments of some of the species.]

About 210 species, mostly tropical. Besides the following. 3 species occur in the southern United States. Type species: Trichomanes crispum L.

1.  Trichomanes BoschiànumSturm.
Filmy-fern.   Bristle-fern.   Fig. 18.
BB-0018 Trichomanes boschianum.png

Trichomanes Boschianum Sturm; v. d. Bosch.  Ned. Kr. Arch. 5²: 160.   1861.

Trichomanes radicans of American writers. Not Sw.

Rootstocks filiform, wiry, tomentose, creeping. Stipes (petioles) ascending, 1–3 long, naked or nearly so; leaves 2–8 long, 8–1½ wide, membranaceous, lanceolate or ovate·lanceolate, 2-3 pinnatifid; pinnae 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 pinnule, the mouth slightly 2-lipped; receptacle more or less exserted, bristle-like, bearing the sessile sporanges mostly near the base.

On wet rocks, Kentucky to Florida and Alabama. Also in the West Indies, Mexico, tropical America, Europe, Asia and Africa.  Summer.