HYMENOPHYLLACEAE - BARRO COLORADO ISLAND

BARRO COLORADO ISLAND

INTRODUCTION 63 INTRODUCTION 63

7. HYMENOPHYLLACEAE

KEY TO THE SPECIES OF GLEICHENIACEAE

Veins of leaf segments 1-forked; leaflet midribs normally covered with brown scales below; leaf segments 8-16 times longer than wide Gleichenia hifida (Willd.) Spreng.

Veins of leaf segments 2-5-forked; leaflet midribs not covered with brown scales below; leaf segments less than 5 times longer than wide:

A pair of accessory pinnae at all but ultimate nodes Dicranopteris flexuosa (Schrad.) Und.

Accessory pinnae lacking, or (rarely) only at lower nodes Dicranopteris pectinata (Willd.) Und.

6. GLEICHENIACEAE

Homosporous, terrestrial herbs, often vinelike; rhizomes long-creeping. Leaves 2-pinnate or more compound (in ours; sometimes pinnate elsewhere), often pseudodichot- omous by abortion of terminal bud, usually coriaceous;

veins free. Sori exindusiate; sporangia few on lower blade surface, in 2 rows along major divisions, each sporangium with a complete transverse medial annulus opening by a longitudinal slit; prothallia green, flat, costate.

Recognized by their vinelike habit and their dichotomously branched, pinnately compound leaves, the sporangia borne along the segments of the pinnatifid pinnae.

Five or six genera and 130-160 species; tropical, subtropical, and subtemperate areas of the Southern Hemi- sphere.

DICRANOPTERIS Bernh.

Dicranopteris flexuosa (Schrad.) Und., Bull. Torrey Bot. Club 34:254. 1907

Similar to D. pectinata, but with a pair of reduced accessory pinnae at most leaf nodes; the plant glabrous throughout; the veins of the leaflets 2-4-forked, darker, not at all raised. Kenoyer 4.

Found in same habitats as D. pectinata. Collected once by Kenoyer, and possibly no longer present on the island.

Southern Mexico to Colombia and along the Ande-. to Brazil and Peru, mainly at lower elevations; West Indies.

In Panama, known principally from tropical moist forest in the Canal Zone, Veraguas, Herrera, Panama, and Darien, but also from premontane wet forest in Panama (Cerro Campana).

Dicranopteris pectinata (Willd.) Und., Bull. Torrey Bot. Club 34:260. 1907

Free-climbing, vinelike, dichotomously branched herb;

rhizome long-creeping, 3-5 mm diam, scabrous from persistent bases of articulate trichomes; primary leaf axes at first erect, eventually arching. Leaflets paired at ultimate nodes, deeply pinnatifid, oblong-lanceolate, mostly 10-25 cm long, 1.5-6 cm wide, sessile, glaucous beneath, glabrate, sometimes with a few brown, stellate scales below; lobes 3-6 mm wide, firm, the veins 3-5-forked, somewhat raised; leaf nodes in lower dichotomies rarely with a pair of reduced accessory pinnae. Sori round, exindusiate, in 2 rows, 1 row on each side of midrib on underside of lobes, each sorus bearing more than 6 sporangia. Croat 4829.

Locally abundant on steep, eroding banks on the shore, particularly on the northern shore of Orchid Island and on Gross Point.

For a description of branching in this genus, see Un- derwood (1907).

Mexico to Brazil, the Guianas, and Bolivia; West Indies. In Panama, known principally from tropical moist forest in the Canal Zone, San Bias, Herrera, Panama, and Darien; known also from tropical dry forest in Panama (Taboga Island) and from tropical wet forest in Colon.

GLEICHENIA J. Sm.

Gleichenia bifida (Willd.) Spreng., Syst. Veg. 4:27. 1827 Erect or subscandent, dichotomously branched herb;

rhizome creeping, scaly; stems, midribs of leaflets above and below, and lobes of leaflets below ± densely covered with brown arachnoid scales, some scales lanceolate with long-ciliate margins. Leaflets paired at ultimate nodes, deeply pinnatifid, oblong, tapered to long-caudate- acuminate apices, 25-45 cm long, 2-8 cm wide, sessile;

lobes sometimes of irregular lengths, mostly 2-4.5 cm long, 2-3 mm wide, moderately thin, the veins 1-forked.

Sori round, in 2 rows, 1 row on each side of midrib on underside of lobes, each sorus usually bearing 4 or fewer sporangia. Croat 11762.

Locally abundant on steep, eroding banks on the shore, on the north side of the island, often growing with the more abundant Dicranopteris pectinata and often prefer- ring the more shaded areas.

Mexico to South America below 2,000 m; West Indies.

In Panama, known from tropical moist forest in the Canal Zone and Darien, but probably more common in premontane wet forest in Col6n, Chiriqui, Code, and Panama.

7. HYMENOPHYLLACEAE

Homosporous epiphytic or terrestrial herbs; stems usually rhizomes with distichous scales, less commonly erect and radially symmetrical. Leaves usually small; leaflets usually 1 cell thick, lacking stomata, usually coiled in bud;

veins usually free. Involucres consisting of urceolate, tubular, or bivalvate marginal extensions of blade (the indusia); sporangia borne on all surfaces of free-ending vein extensions (the receptacles) within the involucre;

sporangia opening by a ± longitudinal slit; spores tetra- hedral or becoming globose; prothallia filamentous or thallose.

78

PTEROPHYTA

KEY TO THE TAXA OF HYMENOPHYLLACEAE

Involucre valvate, not at all tubular Hymenophyllum brevifrons Kunze Involucre tubular Trichomanes

Recognized by their lacy, generally transparent leaves and by their tubular, urceolate, or bivalvate marginal indusia.

Three genera and about 650 species; all tropical and temperate regions of the world.

HYMENOPHYLLUM J. Sm.

Hymenophyllum brevifrons Kunze, Bot. Zeitung (Berlin) 5:185. 1847

Epiphyte; rhizome slender, creeping, branched, with numerous, short, filiform, reddish-brown scales, these ultimately deciduous. Leaves simple, deeply and irregularly divided, translucent, glabrous, usually drying brown and curled; petioles ca 1 cm long; blades ± ovate in outline, ca 1 cm or more long; ultimate lobes usually emarginate, never toothed; veins thick, dichotomously branching several times in lobes. Sori usually near apex of blade, marginal, the indusia bivalved throughout (or at least to middle). Shattuck 1013.

Probably rare; collected once by Shattuck on Zetek Trail.

An inconspicuous plant, usually growing interspersed with mosses. It could easily be overlooked and is possibly more abundant than meets the eye.

Guatemala to Panama and the Guianas. In Panama, known from tropical moist forest in the Canal Zone and Panama and from premontane wet forest in Panama.

TRICHOMANES L.

Many of the smaller, inconspicuous species are easily overlooked and possibly more abundant than they appear.

See the genus key for distinguishing characters of T.

curtii Ros., which has not been identified from BCI but is likely to occur.

Trichomanes diversifrons (Bory) Mett., Sadeb. Nat.

Pfl. 1(4):108. 1899

Terrestrial, mostly 20-30 cm tall; rhizome stout, erect;

petiole bases closely spaced; rhizome and petioles bearing stiff, dark, threadlike, seemingly jointed scales. Leaves simple, dimorphic; petioles on sterile leaves 3-5 cm long; sterile blades deeply pinnatifid, oblong-lanceolate, tapered to very long filiform apex, 3.5-5 cm broad, glabrous above, with short-jointed filiform scales on underside of veins (particularly midrib); lobes mostly to 5 mm broad, acute at apex, ± uncinate-serrate, the veins anas- tomosing, the lowermost lobes reduced; sporophylls linear, denticulate, ca 15 cm long and 6 mm wide, on a petiole 9-18 cm long. Sori immersed into margin; sporangia sessile on a filiform, exserted receptacle. Croat 10813.

Occasional, on steep creek banks in ravines, usually in dark places.

Throughout American tropics. In Panama, known from tropical moist forest in the Canal Zone, San Bias, Veraguas, and Darien; known also from premontane wet forest in Colon (Santa Rita Ridge), from tropical wet forest in Colon and San Bias, and from premontane rain forest in Darien (Cerro Pirre).

Trichomanes ekmanii Wessels-Boer, Acta Bot. Neerl.

11:319. 1962

Epiph5T:e; rhizome slender, creeping, scaly, the petiole bases well spaced. Leaves simple; petioles 3-7 mm long, sparsely scaly; blades obovate or oblong to orbicular, rounded to irregularly lobed especially in upper part, rounded or tapered at base, to 2(3) cm long and 1(1.5) cm wide, the midrib distinct, the lateral veins pinnately arranged, and cross-veins lacking; false vein continuous, submarginal. Sori 4-9 per leaf, together near apex or solitary on apical lobes; indusium wholly immersed in margin, lacking lips and not dark-edged, the tube cylin- drical and broadly expanded at apex. Croat 16515.

Distribution on BCI unknown. Found in wet forests on roots and bases of trees and on fallen logs.

Throughout Central America and northern South America; Greater Antilles. In Panama, known only from tropical moist forest in the Canal Zone.

Trichomanes godmanii Hook, in Baker, J. Linn. Soc, Bot. 9:337. 1866

Tiny epiphyte; rhizome slender, creeping, with fine scales.

Leaves simple, glabrous; petioles 4-10 mm long; blades orbicular or obovate, rounded at apex, tapered to obtuse or acute base, 5-20 mm long and wide, entire or slightly lobed, with a distinct costa and pinnate veins in lower blade and flabellate venation above; false veinlets distinct, reticulate; false vein submarginal. Sori 1-9 in upper part of leaf; indusium wholly immersed in margin, lacking lips and not dark-edged, obconic with the mouth expanded, the receptacle long-exserted. Croat 16202.

Fairly common; seen densely covering all sides of base of Scheelea zonensis (19. Palmae) trunk.

Throughout Central America; Cuba. In Panama, known only from tropical moist forest in the Canal Zone and Panama.

Trichomanes kapplerianum Sturm in Mart., Fl.

Brasil. 1(2):276. 1859

T. hooheri Presl var. minor (Jenm.) Domin

Tiny epiphyte; rhizome slender, creeping, scaly. Leaves simple; petioles very short; young blades often orbicular, cordate; mature blades ovate to oblong, irregularly lobed,

± rounded at apex, rounded to narrowly acute at base.

7-

HYMENOPHYLLACEAE/TRICHOMANES

79

KEY TO THE SPECIES OF TRICHOMANES Plants terrestrial; leaves often more than 20 cm long:

Leaves dimorphic, simple, the sterile leaves pinnatifid, the fertile leaves linear; sori immersed in margin T. diversifrons (Bory) Mett.

Leaves ± monomorphic, 1-pinnate; sori along margins of leaflets except near apex T. pinnatum Hedw.

Plants epiphjftic; leaves less than 10 cm long:

All leaves pinnately lobed, most more than 3 cm long, the costa extending to apex of blade:

Trichomes frequent on blade surface and margins, all trichomes stellate; indusia bell-shaped, immersed, the lips not dark-edged T. polypodioides L.

Trichomes only on margins of blades, the blades otherwise glabrous, the trichomes simple or bifid; indusia tubular, partly exserted, the lips dark-edged T. krausii Hook. & Grev.

At least some leaves not pinnately lobed, most less than 3 cm long, the costa only rarely extending to the apex:

Leaves bearing marginal trichomes but lacking a submarginal false vein; indusia at least partly exserted, with 2 distinct dark-edged lips:

Leaves less than 8 mm long, usually bearing a single terminal sorus T. ovale (Fourn.) Wessels-Boer Leaves more than 1 cm long, usually bearing several to many sori:

Sori often 6 or more per leaf; indusia exserted, not between lobes or in sinuses (species not known from BCI but to be expected) 7". curtii Ros.

Sori rarely as many as 5 or 6 per leaf; indusia half immersed, between lobes T. punctatum Poir. subsp. sphenoides (Kunze) Wessels-Boer Leaves lacking marginal trichomes but bearing a submarginal false vein; indusia wholly im-

mersed, without lips and not dark-edged:

Venation reticulate; mature fertile leaves ± orbicular T. godmanii Hook.

Venation lacking cross-veins; mature fertile leaves elongate:

Submarginal vein continuous; young leaves ± elongate T. ekmanii Wessels-Boer Submarginal vein discontinuous; young leaves often orbicular or cordate

T. kapplerianum Sturm

5-30 mm long, 5-15 mm wide, bearing a distinct midrib, pinnate lateral veins in lower part of blade, flabellate venation above; false vein discontinuous, submarginal.

Sori usually 3-7, together near apex or on small lobes;

indusium wholly immersed in margin, lacking lips and not dark-edged, the mouth expanded; receptacle exserted.

Wilson 87.

Distribution on BCI not known. Forming mats on tree trunks and moist rocks.

Costa Rica to the Guianas and Amazon basin; Lesser Antilles. In Panama, known only from tropical moist forest on BCI and in Bocas del Toro.

Trichomanes krausii Hook. & Grev., Icon. Fil. t.

149. 1831

Tiny epiph5?te; rhizome slender, creeping, scaly. Leaves simple, very thin, somewhat lacy; petioles mostly very short; petioles and lower midribs densely scaly; blades oblong or lanceolate-oblong, irregularly pinnatifid, glabrous except on margins, the segments weakly lobed, 2-4.5 (9) cm long, 1-2.5 cm wide; lobes ± linear, irregular, 1-3 mm broad, separated by broad, open sinuses, a large dark stellate scale on a tooth in the sinus, some of the marginal scales simple or bifid; midrib of lobes extending to apex, almost lacking connected lateral veins;

false veinlets few, partly parallel to margin. Sori several, solitary in upper lobes; indusium partly immersed, its lips semiorbicular, dark-edged. Croat 8789.

Distribution on BCI uncertain. Found on moist, shaded rocks, twigs, and tree trunks to 1,350 m elevation.

Throughout tropical and subtropical America. In Panama, known from tropical moist forest in the Canal Zone and Darien, from premontane wet forest in Panama, and from tropical wet forest in Chiriqui.

Trichomanes ovale (Fourn.) Wessels-Boer, Acta Bot.

Neerl. 11:296. 1962

T. sphenoides Kunze var. minor Ros.

Tiny epiphyte, the blades usually ± appressed. Leaves simple, minute; petioles very short; blades variable, orbicular, ovate, or lanceolate, usually rounded or cordate and broadest at base, 3-8 mm long, 2-6 mm wide, ± entire, with bifid or stellate trichomes on margin; midrib on fertile leaves and some sterile leaves running to apex, the lateral veins pinnate, partly free. Sorus solitary at apex (rarely 2 or 3); indusium partly immersed, at least the lips exserted, the lips dark-edged, small, narrowly winged with stellate scales and with a few rows of brown cells.

Croat 14999.

Distribution on BCI not known. Found on moist, deeply shaded rocks and tree trunks.

Probably throughout the American tropics, but seldom seen because of its small size. In Panama, known only from tropical moist forest in the Canal Zone and Panama.

Trichomanes pinnatum Hedw., Fil. Gen. et Sp. t. 4, f. 1. 1799

Terrestrial, usually 25-50 cm tall; rhizome erect, short, bearing brown, threadlike scales. Leaves 1-pinnate,

8o

PTEROPHYTA

6-30(40) cm long, often with a long leafless tail at apex, the tail sometimes rooting and producing another plant;

petiole and rachis with moderate to sparse, long, threadlike scales; pinnae lanceolate-oblong, blunt to obtuse at apex, obtuse to truncate or subcordate at base (sterile pinnae imbricate at base), 3-6 cm long, 1-1.5 cm wide, minutely and sharply serrate, glabrous except on midrib below, with many lateral, 1-4-forked veins; fertile leaflets somewhat narrower and more widely spaced along rachis.

Sori along margin except very near apex; indusium ± tubular, stalked; receptacle exserted, about as long as tube. Croat 5046.

Occasional, in ravines on steep banks.

Throughout the American tropics. In Panama, known only from tropical moist forest in the Canal Zone and Panama and from tropical wet forest in Panama.

Dalam dokumen Flora of Barro Colorado Island - Introduction (Halaman 72-75)