A Key to the Pteridophytes of Moorea

GROUP 2: Filmy Ferns

1 Plants terrestrial; rhizomes erect 2
  Plants rarely terrestrial, usually epiphytic or epipetric; rhizomes long-creeping 4
2 Laminar tissue not expanded or only consisting of one to two rows of cells on each side of midrib Abrodictyum asae-grayi
  Laminar tissue normally expanded 3
3 Long bristle-like, light reddish hairs present on stipes and rachises; blades light green, membranaceous Callistopteris apiifolia
  Such hairs absent; blades dark green, coriaceous Abrodictyum dentatum
4 Blades covered in fine white hairs, appearing glaucous Hymenophyllum pallidum
  Blades not glaucous 5
5 Rhizomes ca. 2 mm diam. 6
  Rhizomes filiform, less than 1 mm diam. 7
6 Plants epiphytic on tree ferns Abrodictyum caudatum
  Plants terrestrial or epipetric Vandenboschia maxima
7 Rhizomes covered with fine yellow hairs Hymenophyllum flabellatum
  Rhizomes either nearly glabrous or covered with reddish to black hairs 8
8 Rhizomes nearly glabrous; involucres bivalved 9
  Rhizomes covered with reddish to black hairs; involucres tubular or conical 12
9 Marginal hairs present on blades Hymenophyllum digitatum
  Marginal hairs absent from blades 10
10 Blade margins denticulate; involucres bent at ca. 45° to blades Hymenophyllum aff. multifidum
  Blade margins not denticulate; involucres in same plane as blades 11
11 Blade margins undulating Hymenophyllum cf. javanicum
  Blade margins flat Hymenophyllum polyanthos
12 Leaves peltate, tightly appressed to substrate Didymoglossum tahitense
  Leaves not peltate, not appressed to substrate 13
13 False veins absent 14
  False veins present 15
14 Blades flabellate to irregularly pinnatifid, less than ca. 3 cm long; new stipes proliferating irregularly from other stipe bases or blades Crepidomanes minutum
  Blades 2-pinnatifid or more divided, ovate-lanceolate, greater than ca. 3 cm; no such proliferations Polyphlebium borbonicum
15 False veins marginal 16
  False veins submarginal 17
16 Rhizome hairs black, dense; false veins consisting of double row of slightly elongated marginal cells Crepidomanes humile
  Rhizome hairs reddish brown, numerous but not dense; false veins consisting of single row of greatly elongated marginal cells (ca. 4-5 x longer than other laminar cells) Polyphlebium endlicherianum
17 Leaves 1 cm or less; submarginal false veins continuous Crepidomanes kurzii
  Leaves 3 cm or greater; submarginal false veins discontinuous Crepidomanes bipunctatum


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