A Key to the Pteridophytes of Moorea

With Terminology Glossary

Andrew G. Murdock, 2003

Updated by Joel H. Nitta, 2011

Key to major groups given first. Click on group name for key of species in each group.

1 Sporangia borne singly in the axils of leaves or on upper surface of leaves GROUP 1
  Sporangia borne on underside of leaves or on leaf margins 2
2 Blades extremely thin (laminae usually only a single cell layer in thickness between veins); stomata absent GROUP 2
  Blades with laminae more than 3 cells thick; stomata present 3
3 Plants aquatic Marsilea polycarpa
  Plants not aquatic 4
4 Plants epiphytic, epipetric, or hemi-epiphytic 5
  Plants terrestrial (including those with rhizomes in ground but leaves that clamber or climb over other vegetation as often observed in Group 5) 6
5 Leaves simple GROUP 3
  Leaves pinnatifid or more divided GROUP 4
6 Leaves indeterminate; blades pseudodichotomously forked with a resting bud in each axil GROUP 5
  Leaves usually determinate; blades not pseudodichotomously forked 7
7 Leaves simple to 1-pinnate-pinnatifid GROUP 6
  Leaves 2-pinnate or more divided GROUP 7

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.


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

Aerophore: an evanescent spot, swelling, or finger-like projection of thin-walled cells found along the stipe or in the pinna or pinnule axils of some ferns that apparently aids gas exchange with the atmosphere

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

Aristate: bearing a long, stiff, bristle-like apical prolongation of a midrib beyond the margin

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

Farina: a thick, powdery-appearing exudate of glands covering the lamina surface

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

Medial: (used to describe sorus position) borne midway between the costa or costule and the margin

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

Pedate: having the basal basiscopic portions of the basal pinnae more developed and divided than the other portions of the laminae

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

Sporophyll: in ferns, a frond bearing sporangia; in lycophytes, a scale-like microphyll subtending a sporangium

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

Superficial: (used to describe sorus position) on the surface of the lamina, rather than on 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

Wing: (=ala) a long, narrow membrane laterally bordering a stipe, rachis, or costae

Some definitions adapted from:

Lellinger, David B. 2002. A Modern Multilingual Glossary for Taxonomic Pteridology. Pteridologia 3: 1263.

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