Hymenophyllum
(from hymen, a membrane, and phyllon, a leaf). Filmy Fern. ORD. Filices. A genus of about eighty species of stove or greenhouse, rarely hardy, ferns. Fronds delicately membranaceous, simple or compound, never with anastomosing veins. Sori marginal, more or less sunk in the frond, or exserted; involucre inferior, more or less deeply two-lipped or two-valved, toothed or fringed, or entire; receptacle elongated, columnar, exserted or included. Except where otherwise stated, the species described below require stove treatment. For culture, see Ferns.
H. abruptum (abrupt). sti. about 1/4in. long, very slender. fronds 1/2in. to 1in. long, 1/4in. to 1/2in. broad, oblong, pinnatifid nearly to rachis; pinnae linear, about 1/4in. long. sori one or two to a frond, terminal on the apex. West Indies and tropical America, 1859. (H. S. F. i. 31.) H. aeruginosum (verdigris-covered).* sti. 1in. to 2in. long, hairy. fronds 2in. to 3in. long, about, or scarcely 1in. broad, lanceolate or ovate-acuminate, tripinnatifid; pinnae often much imbricated, the lower ones flabellate, divided down nearly to the rachis; surface and margin pubescent. sori two to twelve, terminal on the segments. Tristan d' Acunha. H. aspleniodes (Asplenium-like). sti. 1in. to 2in. long, slender. fronds 2in. to 4in. long, 1/2in. to 1in. broad, pendulous, oblong in general outline, pinnatifid nearly to rachis. sori one to four, terminal on the segments. Tropical America, 1859.
H. bivalve (two-valved). sti. 2in. to 4in. long, wiry. fronds ovate-triangular, tripinnatifid, 3in. to 8in. long, 2in. to 3in. broad; lower pinnae triangular-acuminate; ultimate segments linear, two to three lines long, spinulose-dentate. sori very numerous, often six to eight on a single pinnule. New Zealand. (H. S. F. i. 35D) H. Boryanum (Bory's). A synonym of H. ciliatum.
H. caudiculatum (tailed). sti. 4in. to 6in. long, wiry, broadly winged above. fronds 6in. to 12in. long, 2in. to 3in. broad, ovate-acuminate, tripinnatifid; lower pinnae rhomboidal-lanceolate, erecto-patent, divided down to the rachis. sori two to twelve to a pinna, placed at the apex of the segments on both sides. Brazil, Peru, and Chili.
H. ciliatum (ciliated).* sti. 1in. to 2in. long, ciliately and decurrently winged above. fronds oblong, acuminate, tripinnatifid, 2in. to 6in. long, 1in. to 2in. broad at the centre; lower pinnae oblong or rhomboidal, with a broad central undivided portion. sori two to twelve on a pinna, placed at the end of the lateral segments on both sides. Tropical regions of both hemispheres, 1859. SYN. H. Boryanum, H. Plumieri.
H. crispatum (curled). A synonym of H. javanicum.
H. demissum (hanging down).* sti. 4in. to 6in. long, erect, firm. fronds 4in. to 12in. long, 3in. to 4in. broad, ovate-triangular, three or four times pinnatifid; lower pinnae 2in. to 3in. long, triangular-rhomboidal, divided nearly to the rachis. sori twenty to thirty to a pinna, terminal and axillary in the segments on both sides. New Zealand, Philippines, &c., 1858. Greenhouse.
H. dilatum (swollen). sti. 2in. to 4in. long, erect, wiry. fronds 6in. to 12in. long, 4in. to 6in. broad, ovate-lanceolate, tripinnatifid; lower pinnae rhomboidal-lanceolate, divided nearly to the rachis. sori two to twelve to a pinna, terminal or axillary on the segments on both sides. New Zealand. Greenhouse.
H. falklandicum (Falkland Islands). sti. 1/2in. to 3/4in. long, filiform. fronds oblong, pinnatifid, 1in. to 2in. long, 3/8in.to 1/2in. broad; pinnae erecto-patent, sessile, upper simple, lower deeply bifid or trifid; lobes ciliate-dentate. sori solitary. Falkland Islands. Greenhouse. H. fimbriatum (fringed). A synonym of H. javanicum.
H. flabellatum (fan-like). sti. 2in. to 4in. long, firm, erect. fronds 4in. to 12in. long, 2in. to 4in. broad, ovate-acuminate, tripinnatifid, flaccid; lower pinnae 1in. to 2in. long, broadly rhomboidal-acuminate, divided to the rachis. sori six to twenty to a pinna, terminate on the lateral segments. Australia, New Zealand, &c., 1859. Greenhouse. SYN. H. nitens.
H. flexuosum (flexuous). A synonym of H. javanicum.
H. hirsutum (hairy).* sti. 1in. to 2in. long, slender. fronds linear-oblong, once pinnatifid, 2in. to 6in. long, about 1/2in. broad, slender, flaccid, often pendulous, hairy over the surface; pinnae short, close. sori one to four on a pinna. South America, Madagascar, 1823.
H. hirtellum (small-haired). sti. 1in. to 4in. long, tomentose. fronds ovate-acuminate, tripinnatifid, 3in. to 6in. long, 2in. to 3in. broad; lower pinnae rhomboidal-lanceolate, with a narrow central undivided portion; lower pinnules pinnatifid, with long, narrow-linear ciliated segments. sori two to twelve to a pinna, placed at the end of the lateral segments on both sides. West Indies, Mexico, &c., 1859. (H. S. F. i. 31D.) H. javanicum (Javanese). sti. 2in. to 4in. long, erect, margined above with a broad crisped wing. fronds 4in. to 8in. long, 3in. to 4in. broad, triangular, tripinnatifid; lower pinnae 1 1/2in. to 2in. long, triangular-rhomboidal, divided down to a narrow crisped centre. sori six to twenty to a pinna, terminal and axillary on the segments on both sides. India to Australia, &c. Greenhouse. SYNS. H. erispatum, H. fimbriatum (H. S. F. i. 36), H. flexuosum. H.nitens (shining). A synonym of H. flabellatum.
H. Plumieri (Plumier's). A synonym of II. ciliatum.
H. polyanthos (many-flowered).* sti. 2in. to 3in. long, slender. fronds 2in. to 8in. long, 1in. to 3in. broad, ovate-oblong, tripinnatifid; lower pinnae triangular-rhomboidal, divided down to a narrow centre. sori two to twelve to a pinna, terminal or axilary on the segments of both sides. Tropics, 1824. SYN. H. protrusum. (H. S. F. i. 37B.) H. protrusum (protruded). A synonym of H. polyanthos. H. pulcherrimum (very pretty).* sti. 3in. to 4in. long, wiry, erect, winged down to the base. fronds 6in. to 12in. long, 4in. to 6in. broad, ovate-triangular, three or four-pinnatifid; lower pinnae 2in. to 3in. long, lanceolate-rhomboid. sori numerous, axillary and terminal on the segments of both sides. New Zealand. Greenhouse.
H. rarum (rare). sti. very slender, 1in. to 3in. long, fronds flaccid, pendent, 2in. to 6in. long, 1in. to 2in. broad, oblong, bipinnatifid; pinnae simple, linear or forked or pinnatifid. sori large, terminal on the segments of the upper pinnae. New Zealand to Cape Colony. Greenhouse. H. scabrum (rough). sti. 2in. to 4in. long, wiry, ciliated. fronds 6in. to 15in. long, 2in. to 5in. broad, ovate-acuminate, tripinnatifid; lower pinnae 2in. to 3in. long, oblong-rhomboidal, acuminate, divided nearly to the rachis. sori six to twenty to a pinna, terminal on the lateral segments on both sides. New Zealand, 1859. Greenhouse.
H. sericeum (silky). sti. 2in. to 4in. long, wiry. fronds pendent, 6in. to 24in. long, 2in. to 3in. broad, elongate-oblong, obtuse or acuminate, simply pinnatifid; pinnae 1in. to 2in. long, numerous, opposite, very variable in division. sori numerous to a pinna, small, terminal on the apex of the pinnae and lateral segments. Tropical America, 1859.
H. tunbridgense (Tunbridge).* sti. 1/2in. to 1 1/2in. long. fronds oblong-lanceolate, 1in. to 3in. long, 1/2in. to 1in. broad, pinnate throughout; pinnae distichous, flabellato-pinnatifid; lobes linear, one to three lines long, spinulose, serrated, as is also the compound involucre. Temperate regions (Britain). Hardy.
H. unilaterale (one-sided). This differs from H. tunbridgense in the more ovoid and turgid involucre, in the darker green and more rigid fronds, with the pinnae pinnatifid on the upper side chiefly. Britain. Hardy. SYN. H. Wilsoni.
H. Wilsoni (Wilson's) A synonym of H. unilaterale.