Melpomene

Smith, Alan R., Kessler, Michael, León, Blanca, Almeida, Thaís Elias, Jiménez-Pérez, Iván & Lehnert, Marcus, 2018, Prodromus of a fern flora for Bolivia. XL. Polypodiaceae, Phytotaxa 354 (1), pp. 448-450 : 448-450

Key to the Bolivian species of Melpomene

1 Rhizome scales with marginal glands .............................................................................................................................................. 2

– Rhizome scales without marginal glands, these restricted to the scale apex .................................................................................... 6

2 Costae visible, segments linear-oblong, at least acroscopically decurrent onto rachis ....................................................... M. firma

– Costae not visible, segments deltate to oblong, basally not decurrent along rachises but often cuneate or contracted on the acroscopic side .................................................................................................................................................................................................... 3

3 Rhizomes thick, wiry, and long-creeping, fronds separated; scales more than 1 mm long, max. 50–60 cells wide across base ........ ............................................................................................................................................................................................. M. erecta

– Rhizomes compact to very short-creeping, fronds clustered; scales very small, usually <1 mm long, max. 12 cells wide across base ................................................................................................................................................................................................... 4

4 Petioles marginate to alate, short (<1/4 of frond length); segments broadly adnate to the rachis ........................... M. melanosticta

– Petioles terete, rather long (ca. 1/3 to 1/2 of frond length); segments constricted towards the rachis ............................................. 5

5 Segments abaxially concave with strongly inrolled margins, almost conduplicate, margins entire or shallowly sinuate .................. ................................................................................................................................................................................... M. allosuroides

– Segments abaxially ± flat, margins usually notably lobed ............................................................................................... M. gracilis

6 Apical glands a dense mass of branched hairs at the truncate rhizome scale apex (multicellular base) ............. M. caput-gorgonis

– Apical gland single, or gland a simple or branched hair originating from one basal cell at the acute rhizome scale apex .............. 7

7 Rhizomes horizontally creeping, branching, with well spaced fronds ............................................................................................. 8

– Rhizomes ascending to erect, unbranched, with fronds approximate to fasciculate ...................................................................... 16

8 Scales 40–60 cells across, rhizomes 1.5–2.0 mm diam, segments oblong, weakly contracted basally ............................. M. erecta

– Scales 10–32 cells across, rhizomes usually <1.5 mm diam., segments deltate or rounded, rarely oblong, always fully adnate ... 9

9 Sori without hairs, exceptionally single sori with 1 to 2 hairs ............................................................. M. moniliformis var. minor

– Sori regularly with hairs ................................................................................................................................................................. 10

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