Monographs Details: Melpomene vernicosa (Copel.) A.R.Sm. & R.C.Moran
Authority: Lehnert, Marcus. 2013. Grammitid ferns (Polypodiaceae). II. . Fl. Neotrop. Monogr. 112: 1--121. (Published by NYBG Press)
Family:Polypodiaceae
Synonyms:Ctenopteris vernicosa Maxon ex, Grammitis vernicosa (Maxon ex Copel.) C.V.Morton, Polypodium pilosissimum var. major Klotzsch, Ctenopteris pennellii Copel., Grammitis pennellii (Copel.) C.V.Morton, Melpomene pennellii (Copel.) A.R.Sm. & R.C.Moran
Description:Species Description - Plants epiphytic in moss layers, sometimes terrestrial. Rhizomes stout, very short-creeping to erect, (1 5_)1 8—2.2 mm diam. Fronds to 26 cm long, erect to patent, inserted onto the rhizomes in narrow angles, closely arranged (internodes 0.5-2.0 mm), caespitose. Rhizome scales 4.0-6.2 x 0.4-0.5 mm, 10-18(-20) cells wide across bases, clathrate, dark brown to blackish, strongly iridescent, narrowly cordate at bases, long-acute to attenuate at tips, apical cells 3-8, in nodding clusters or furcately arranged. Petioles (20-)45-66 mm long, (0.8—)1.0—1.2 mm thick, terete or rarely some also very narrowly marginate, densely hairy, with dark brown setiform hairs (0.6—)1.0— 2.0 mm long; simple and branched clavate hairs sparse or absent. Laminae to 150-210 x 36 mm, broadly elliptic (broadest in the middle), decurrent in proximal half, truncate at bases, acute at tips, abaxially shiny. Rachises very dark brown to black, planar adaxially, strongly hemispherically protruding abaxially, weakly to strongly hairy abaxially, glabrous adaxially or only weakly hairy proximally; setiform/ciliform hairs castaneous to black, 0.8-1.2 mm long, some basally with 2-3 vesiculose hyaline cells with branches identical to those of clavate hairs. Largest segments 16.0-20.0 x 3.0-3.5 mm (5-6 times longer than broad), segments patent or nearly so (80-90°), weakly gibbose, equilateral at bases, fully adnate, linear-oblong, the tips obtuse, often with hyaline margins; midveins not clearly visible, weakly protruding in dried specimens; proximal segment pairs sometimes markedly smaller than subsequent segments (1/2-1/3 of longest segments), but not auriculiform; setiform hairs to 1.5 mm long clustered in sori, scattered along the midveins, but also evenly distributed on laminae abaxially, absent adaxially and on the margins; hydathodes present, weakly immersed in laminar tissue. Sori 3-14 pairs per segment, 3-8 setiform hairs to 1.5 mm long within each sorus.

Discussion:Melpomene vernicosa is one of the larger species in the genus, and differs from M. xiphopteroides mainly in the size of parts: rhizome diam. 1.8-2.2 mm vs. 0.6-0.8 mm and petiolar thickness 1.0—1.2 mm vs. 0.6-0.8 mm. These differences are relative and do not change with absolute size (i.e., plants of the same frond length have stouter rhizomes and petioles in M. vernicosa than in M. xiphopteroides). Similarly size-independent are the petiolar margins/alae (generally absent in M. vernicosa vs. present in M. xiphopteroides).

Melpomene vernicosa is found more commonly at the upper limit of its elevational range, above 1800 m, whereas M. xiphopteroides occurs mainly below 2000 m. However, their elevational ranges overlap completely. Geographically, the overlap is also considerable Both occur from Mexico to Colombia and south to northern Peru, but whereas M. vernicosa is restricted to the continent north of the Amotape-Huancabamba region, M. xiphopteroides extends to the Greater Antilles and south to Bolivia and SE Brazil.

The Venezuelan collections Smith et al. 1570 and 1593 (UC) have weakly marginate petioles but judging from other characters (e.g., the lacquer shine of the laminae), they clearly belong to Melpomene vernicosa. This indicates a certain ambiguity of the petiolar character, which is otherwise reliable for distinguishing M. vernicosa with terete petioles from M. xiphopteroides with marginate to alate petioles.

The branched clavate hairs with one dark acicular tip, which may occur abaxially on the rachises of Melpomene vernicosa, are unique within the genus (Fig. 1G). These hairs comprise an infallible, reliable, distinguishing character but, unfortunately, are not present on all specimens. It is very likely that they are shed with age or while drying, which happens regularly to clavate hairs. Similar mixed hairs occur in other grammitid genera, e.g., Lellingeria tungurahuae (Rosenst.) A. R. Sm. & R. C. Moran (de la Sota et al., 2000).

The combination of these apparently minor differences of Melpomene vernicosa compels me to recognize it as a distinct species and not a synonym of M. xiphopteroides, as done by Labiak & Prado (2005a).

Melpomene personata can be distinguished from M. vernicosa by its thinner, longer petioles (to 150 mm long, 0.6(-0.8) mm thick vs. to 66 mm long, (0.8-)1.0-1.2 mm thick in M. vernicosa); larger internodes (3-10 mm vs. 0.5-2.0 mm); and frond characters (pendent with mostly acute and ascending (60-70°) segments vs. patent to erect obtuse and patent (80-90°) segments).

The name refers to the shiny adaxial surfaces of the laminae (Latin vernix = lacquer, varnish).
Distribution:Puntarenas Costa Rica Central America| Chiapas Mexico North America| Oaxaca Mexico North America| San José Costa Rica Central America| Quiché Guatemala Central America| Lempira Honduras Central America| Azuay Ecuador South America| Loja Ecuador South America| Pastaza Ecuador South America| Zamora-Chinchipe Ecuador South America| Amazonas Peru South America| Mérida Venezuela South America| Trujillo Venezuela South America| Antioquia Colombia South America| Cundinamarca Colombia South America| Huila Colombia South America| Nariño Colombia South America| Santander Colombia South America|