Monographs Details: Melpomene caput-gorgonis Lehnert
Authority: Lehnert, Marcus. 2013. Grammitid ferns (Polypodiaceae). II. . Fl. Neotrop. Monogr. 112: 1--121. (Published by NYBG Press)
Description:Species Description - Plants predominantly epiphytic, growing in moss layers, rarely epilithic. Rhizomes moderately to short-creeping, horizontal, 1.0-1.5 mm diam. Fronds to 35-42 cm, arching to pendent, inserted onto the rhizome at right angles, closely arranged (internodes mm). Rhizome scales to 6.5 x 0.8-10 mm, (18 -)20-26(-32) cells wide across bases, clathrate, auburn to brown, strongly iridescent, broadly cordate to pseudopeltate, with obtuse to truncate tips ending in rows 3—4 cells; apical cells numerous, sitting clustered on the wide tips. Petioles 15-50(-70) mm long, 0.6-0.8(—1-0) mm thick, decurrently marginate from the laminar bases, with brown ciliform hairs (1.0-2.0 mm) on both sides, simple and branched clavate hairs of crosiers and young fronds sometimes persistent on older fronds, but generally glabrescent. Laminae firm-chartaceous, rarely coriaceous {Lehnert 781), to 300 (_350) x 14-22 mm, narrowly elliptic (broadest in the middle), decurrent at bases, acute to attenuate at tips, sometimes caudate. Rachises dark brown, flat and slightly sunken between segments adaxially, weakly hemispherically protruding abaxially, glabrous except for the proximal part, with ciliform hairs as on petioles. Largest segments 4.5-9.0(-12.0) x 3.2-3.8 (-5.0) mm (1.5-3 times longer than broad), segments weakly ascending (70-80°), oblong to lunate, equilateral at bases or weakly basiscopically decurrent, fully adnate, the tips obtuse to round; midveins not visible or obscurely so abaxially, especially in dried specimens; proximal pairs markedly smaller than the central segments, inequilateral at bases, basalmost auriculiform (Lehnert 368), but never trapezoid; rarely with a few ciliform hairs scattered along the segment margins; hydathodes present. Sori 2-4 pairs per segment, with 3-10 receptacular and circumsoral, ciliform hairs 1.0-1.5 mm long.

Discussion:The most distinguishing feature of Melpomene caput-gorgonis is the broad rhizome scale with the abundant apical cells that appear as clustured, branched, clavate hairs. No other species of Melpomene has scale apices several cells wide that provide a base for several apical hairs.

Melpomene flabelliformis can be distinguished from M. caput-gorgonis by its distant fronds and glabrous or glabrescent petioles (vs. fronds close and petioles persistently hairy in M. caput-gorgonis). Melpomene flagellata is generally more slender in habit and most features (i.e., laminae to 9(—16) mm broad vs. to 22 mm in M. caput-gorgonis) and has thinner and ascending rhizomes with narrower scales and also some truncate segment tips (vs. always obtuse to round).

Melpomene caput-gorgonis grows together with M. paradoxa, which can be distinguished by its less hairy petioles (rather densely hairy with hairs 1-2 mm long in M. caput-gorgonis vs. sparsely hairy with hairs to 1.2 mm long in M. paradoxa) and shorter segments (only as long as broad vs. 1-3 times longer than broad). Melpomene paradoxa also grows in patches with the fronds erect to arching, whereas M. caput-gorgonis forms solitary plants with arching to pendent fronds.

The name refers to the multiple apical cells on the scale tips. These cells resemble the head of Medusa, one of the Gorgons in Greek mythology, which had snakes instead of hair (Latin caput = head).
Distribution:La Paz Bolivia South America| Cusco Peru South America|