Australian Biological Resources Study
Fern definitions mostly compiled by Mary D.Tindale
(definitions of conifer terms provided by K.D.Hill)
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pachycaul: thick-stemmed, sparingly branched and ±succulent, with a massive parenchymatous pith and cortex and relatively little secondary wood.
paleate: clothed with scales.
palmate: of a leaf, divided into several leaflets which arise at the same point. cf. palmatifid, pinnatifid.
palmatifid: of a leaf, deeply (but not completely) divided into several lobes which arise (almost) at the same level. cf. palmate, pinnatifid.
papilla: a small elongated protuberance on the surface of an organ, usually an extension of one epidermal cell. adj. papillose.
paraphysis: sterile filaments occurring among the sporangia of some ferns. pl. paraphyses.
parenchyma: plant tissue consisting of mature living cells that are relatively unspecialised in function.
pectinate: comb-like.
pedate: of a palmate or palmately-lobed leaf, having the lateral segments divided again.
pedicel: the stalk of a sporangium.
peduncle: the stalk of a sporocarp, e.g. in Marsilea.
peltate: having the stalk attached to the lower surface usually at or near the centre; umbrella-shaped.
perine: an outer (perisporial) spore wall, present in some families and genera of ferns. cf. exine.
peripheral fibre strands: multicellular fibre strands which strengthen the periphery of the leaf in some Isoetes species.
perispore: the folded membrane of most spores, forming an ornamental external covering.
persistent: remaining attached to the plant beyond the expected time of falling.
phanerocotular: mode of germination where cotyledons emerge from the seed and above ground.
phyllopodium: an outgrowth from the stem to which a stipe is articulated.
pilose: hairy, the hairs soft and clearly separated but not sparse.
pinna: a primary segment of the lamina in a compound leaf. pl. pinnae.
pinnate: of a lamina, divided into pinnae, with the pinnae (leaflets) arising at points along the rachis.
pinnatifid: cut deeply (but not to midrib) into lobes that are spaced out along the axis. cf. palmate, palmatifid.
pinnatisect: pinnately dissected down to the midrib but having the segments confluent with it.
pinnule: a leaflet, i.e. ultimate segments of the lamina.
pit: of a cell wall, a small hollow or depression.
plagiotropic: mode of growth of lateral branches, growing horizontally away from the leading shoot and maintaining a different morphology, especially in conifers.
platyspermic: describing flat and bilaterally symmetrical seeds.
pluricellular: having many cells, as in some hairs.
polymorphic: having more than two distinct morphological variants.
polyploid: having more than two of the basic sets of chromosomes in the nucleus. cf. diploid, haploid.
proliferous: having adventitious leaf buds which produce new plants.
prothallus: the gametophyte of a fern or fern ally.
protostele: a simple primitive type of stele having a solid central vascular core.
proximal: near to the point or origin of attachment. cf. distal.
pseudo-: false; apparent but not genuine.
ptyxis: pattern of folding and rolling shown during leaf development.
pubescent: clothed with short soft erect hairs.
punctate: marked with dots, depressions or translucent glands.
pustule: a blister-like prominence, often in which a sorus occurs. adj. pustulate.
pyriform: pear-shaped.
quadrate: squarish.