A Key to the Pteridophytes of Moorea

With Terminology Glossary

Andrew G. Murdock, 2003
(Note: This key is not fully complete - it does not include plants first found after 2002, but should suffice for nearly all ferns on Moorea)
1 Leaves with single, unbranched veins, or leaves very inconspicuous, veinless 2
  Leaves with multiple and/or branched veins 6
2 Spores of two kinds, naked, bracts ± uniform, stems erect, leaves dimorphic and in two rows Selaginella banksii
  Spores all of one kind, naked or in capsules (synangia) 3
3 Sporangia naked, stems forked and freely braching, strobili nodding 4
  Sporangia in capsules several mm in diameter (synangia) 5
4 Plant terrestrial, strobili simple Lycopodiella cernua
  Plant epiphytic, strobili long, forking Huperzia phlegmaria
5 Stems unbrached, leaves obvious, typically found on tree ferns Tmesipteris gracilis
  Stems forked, triangular in cross-section, leaves scale-like not obvious Psilotum nudum
6 Aquatic with clover-like leaves Marsilea polycarpa
  Terrestrial, epiphytic, or lithophytic without clover-like leaves 7
7 Huge ferns (fronds up to 8 meters long but not tree ferns), with fleshy stipules and stems to several cm thick 8
  Fronds without stipules 9
8 Sporangia of each sorus contiguous but not fused, pinnule tips ± sterile, common Angiopteris evecta
  Sporangia fused, forming synangia, stipe frequently spotted, uncommon Marattia salicina
9 Sporangia without annulus 10
  Sporangia with annulus 11
10 Terrestrial, sterile segment basally cordate Ophioglossum reticulatum
  Epiphytic, sterile segment elongate Ophioglossum pendulum
11 Lamina one cell thick between veins, sori on end of veins 12
  Lamina thick enough to have epidermis and other tissue 17
12 Rhizome creeping or scandent, coarse, fronds frequently over 5 cm long 13
  Rhizome creeping, filiform, fronds rarely over 5 cm long 14
13 Fronds clear green, thin Trichomanes societense
  Fronds dark green, harsh Trichomanes dentatum
14 Fronds peltate Trichomanes tahitense
  Fronds pinnatifid or pinnate 15
15 Fronds hairy, sometimes glaucous Trichomanes pallidum
  Fronds neither hairy nor glaucous 16
16 Fronds with submarginal false vein Trichomanes bipunctatum
  Fronds lacking submarginal false vein Trichomanes humile
17 Blades dichotomously or pseudodichotomously compound 18
  Blades not dichotomous, annulus longitudinal 20
18 Sori dorsal, annulus transverse, forming thickets on dry slopes Dicranopteris linearis
  Sporangia or sori in specialized spikes 19
19 Fronds erect, fan-shaped and branching Schizaea dichotoma
  Rachis scandent, of indefinite length, often climbing Lygodium reticulatum
20 Fronds simple, entire or nearly so 21
  Fronds pinnatifid or more divided 27
21 Sporangia on a greatly narrowed linear apical segment Belvisia spicata
  Sporangia not on a linear apical segment 22
22 Leaves grass-like with sorus along each margin Haplopteris elongata
  Leaves not grass-like, sori various 23
23 Sori irregularly following veins 24
  Sori round, roundish, or, if linear, oblique to costae 25
24 Costa nearly obsolete, frond broad, apex frequently forked Antrophyum reticulatum
  Stipe not winged, apex acute or acuminate Antrophyum plantagineum
25 Sori oblique to costae, with linear indusia, forming "birdís nests" Asplenium australasicum
  Sori round or roundish 26
26 Fronds slender and elongate, with scales Pyrrosia serpens
  Fronds without scales, large Microsorum punctatum
27 Sporangia spread over surface, not in sori 28
  Sporangia in dicrete sori 32
28 Sori on distal pinnae, others sterile, pinnae frequently with irregular margins Acrostichum aureum
  Sori on wholly fertile fronds 29
29 Plants terrestrial, rhizome not climbing into trees Bolbitis lonchophora
  Plants hemiepiphytic, rhizome climbing into trees 30
30 Leaflet margin cartilaginous Lomariopsis brackenridgei
  Margins not cartilaginous 31
31 Veins of sterile blades reticulate Lomagramma tahitensis
  Veins of sterile blades free Teratophyllum wilkesianum
32 Sporangia in linear elongate sori 33
  Sori round, roundish, marginal, or following veins 41
33 Sori parallel to costae 34
  Sori oblique to costae 35
34 Fertile and sterile fronds alike Blechnum orientale
  Fertile fronds contracted with much narrower pinnae Blechnum raiateensis
35 Some sori 2-sided or bent across vein 36
  Sori all 1-sided, never curved across vein 38
36 Lower pinnules pinnate Diplazium grantii
  Lower pinnules entire to pinnatifid 37
37 Pinnules deeply pinnatifid, lowest acropetal sorus 1-sided, others 2-sided Diplazium harpeodes
  Pinnules entire or toothed, sori 1- or 2-sided Diplazium ellipticum
38 Fronds pinnate 39
  Fronds bipinnatifid to more divided 40
39 Pinnae linear, spurred, margins dentate, apices obtuse Asplenium tenerum
  Pinnae rhomboid-deltoid, spur rounded, margins serrate, apices acute Asplenium polyodon
40 Fronds bipinnatifid, pinnae long acute, margins crenulate Asplenium caudatum
  Fonds at least tripinnate, resembling a large filmy fern Asplenium gibberosum
41 Sori following veins, typically obscured by white resinous farina Pityrogramma calomelanos
  Sori round, roundish, or marginal 42
42 Sori marginal or submarginal, not round 43
  Sori round or roundish 50
43 Exindusiate or indusium opening towards margin, not formed by reflexed margin 44
  Indusium formed by reflexed margin; plants terrestrial 45
44 Exindusiate, frond pinnatifid or pinnae adnate by entire base; plants epiphytic Prosaptia subnuda
  Indusium opening towards margin, superficially similar to Adiantum spp. Lindsaea propinqua
45 Fronds seriate on a long, creeping rhizome; sori on tips of free veins Hypolepis tenuifolia
  Fronds clustered; sori on marginal vein or inside indusia 46
46 Sori on marginal vein connecting vein-tips; ultimate segments with distinct midrib, segment neither fan-shaped nor trapeziform 47
  Sori in the inside of indusium; ultimate segments fan-shaped or trapeziform, lacking distinct midrib 48
47 Segments up to 15 mm long, lowest pinnae tripinnatifid Pteris tripartita
  Larger segments over 30 mm long Pteris comans
48 Ultimate segments fan-shaped Adiantum raddianum
  Ultimate segments trapeziform 49
49 Ultimate segments 3-4 cm wide; stems shiny black, lacking hairs Adiantum trapeziforme
  Ultimate segments <2 cm wide; stems brown with minute hairs Adiantum hispidulum
50 Tree ferns 51
  Not tree ferns 52
51 Costal scales with dark spreading teeth; stipe dark brown; stipe scales with apical setae, not glaucous Alsophila tahitensis
  Costal scales lacking; stipe light brown; stipe scales with marginal setae, glaucous Sphaeropteris medullaris
52 Sori without indusia or rarely with vestigial indusia 53
  Sori consistently with indusia 59
53 Fronds pinnate or pinnatifid 54
  Fronds bipinnatifid or decompound 55
54 Without free included veinlets Plesioneuron attenuatum
  Free included veinlets present, rarely with vestigial indusia Tectaria tahitensis
55 Veins free, fronds rarely over 10 cm long Ctenopteris blechnoides
  Veins reticulate, fronds over 10 cm long 56
56 Sori in regular rows, up to 5 mm in diameter, yellow 57
  Sori not in regular rows 58
57 Pinnae more or less alternate, lobes rounded, frond less than 1 m Microsorum grossum
  Pinnae more or less opposite, fronds commonly over 1 m long Microsorum membranifolium
58 Sori superficial, fronds rarely over 50 cm long, margin regular, lobes acute Microsorum commutatum
  Sori slightly sunken, fronds to over 1 meter long, margin highly irregular Microsorum x maximum
59 Veins anastomosing 60
  Veins free 61
60 Lowest pinnae reduced and remote; without sessile spherical glands on lower surfaces Sphaerostephanos invisus
  Lowest pinnae reduced to rudiments; with sessile spherical glands on lower surfaces Sphaerostephanos subpectinatus
61 Stipes articulate 62
  Stipes not articulate 65
62 Blades 1-pinnate; indusia fixed by base only 63
  Blades 2-pinnate or more; indusia fixed by base and sides 64
63 Frond coriaceous Pachypleuria pectinata
  Frond not coriaceous Arthropteris palisotii
64 Indusia cylindrical, truncate Davallia solida
  Indusia ovate with free apex Davallia denticulata
65 Blades 2-pinnate or more, pinnae not articulate to rachis; without stolons 66
  Blades 1-pinnate, pinnae articulate to rachis; with stolons 69
66 Indusia peltate Arachniodes aristata
  Indusia not peltate, fixed 67
67 Indusia fixed by base and sides Microlepia scaberula
  Indusia reniform, fixed by sinus 68
68 Minor rachises bearing ciliate, whitish scales Macrothelypteris polypodioides
  Minor rachises bearing entire, brown scales Ctenitis sciaphila
69 Indusia broadly reniform Nephrolepis cordifolia
  Indusia circular or nearly so 70
70 Sori near the margins, all parts scaly Nephrolepis hirsutula
  Sori not marginal, scales lacking Nephrolepis exaltata


Adapted from:

Murdock, A. G. and A. R. Smith. 2002. Pteridophytes of Moorea, French Polynesia, with a new species, Tmesipteris gracilis. Pacific Science, 57 (3).

Copeland, E. B. 1932. Pteridophytes of the Society Islands. Bernice P. Bishop Museum Bulletin 93: 1–86.

Glossary:

Acropetal: occurring on the side of a pinna that is nearest the apex of the frond

Anastamosing: in reference to veins, joining to form areoles (i.e. space enclosed by veins)

Annulus: the structure on some sporangia responsible for dehiscence of spores (often appears worm-like, spring-like, or accordion-like)

Apical: towards the tip or apex

Articulate: jointed, having a clear place of separation

Axis: a midrib or main stalk

Bipinnatifid: pinnatifid with lobes also pinnatifid

Cartilaginous: thick and translucent

Ciliate: conspicuously bearing cilia (minute hair-like segments)

Cordate: heart-shaped (in the stereotypical sense)

Coriaceous: thick and tough, leathery

Costa: (plural = costae) the axis of a pinna

Crenulate: minutely scalloped

Crozier: (aka. Fiddle-head) the typical curled form of a growing frond

Decompound: at least 1-compound

Dentate: with toothed margins

Dichotomous: regularly branching into segments of equal length

Dimorphic: having two distinct morphologies

Distal: towards the tip; apical (opposite = proximal)

Epiphytic: growing on other plants

Exindusiate: lacking an indusium

Filiform: thread-like

False-Vein: a more or less translucent line on a pinna that resembles a vein but is not connected to other veins

Free included veinlets: small veins that terminate in an areole (i.e. a space enclosed by other veins)

Frond: the entire leaf (blade + stipe)

Glaucous: thinly coated with a white waxy substance

Hair: a single cell or chain of single cells that protrudes from any tissue (compare scale)

Indusium: a cover for the sorus (called “false” if formed by recurved leaf margin)

Lithophytic: (aka. Epipetric) growing on rocks

Marginal: occurring along the margin of any surface

Oblique: at an angle to a reference line (not parallel or perpendicular)

Pinna: (plural = pinnae) primary division of a leaf blade

Pinnate: two rows of pinnae on opposing sides of an axis (rachis or costa)

Pinnatifid: deeply cut into lobes in a pinnate fashion, but not into individual pinnae

Rachis: the axis of a fern blade which represents the continuation of the stipe

Reniform: kidney-shaped

Reticulate: forming a net

Rhizome: the stem of a fern, often creeping

Scale: similar to a hair but several cells wide, typically flattened

Scandent: climbing

Seriate: in a contiguous series

Serrate: toothed like a knife or saw

Seta: (plural = setae) a type of hair that is long, thin, and often round (also called a bristle)

Sinus: an indentation separating a surface into lobes

Sorus: a group of sporangia, often round or linear

Stipe: the stalk of a frond that attaches to the rhizome and continues into the rachis

Stipule: in members of the Marattiaceae, a fleshy appendage, a pair of which are found at the base of every stipe, and perhaps serve to protect young croziers

Stolon: a laterally creeping stem, either above or below ground, that produces new shoots and roots

Submarginal: closer to the midrib than the margin

Synangia: a group of sporangia fused together into one structure (seen in Marattiaceae and Psilotaceae, albeit in very different forms)

Terrestrial: growing on the ground

Transverse: lying across; in reference to an annulus, not vertical, more or less horizontally oriented

Trapeziform: trapezoidal; asymmetrically four-sided

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