Word Description
Abortive(Of spores): not completely developing and infertile
AcroscopicFacing towards the apex (of frond or pinna)
AcuteAngle less than 90°
AdnateAttached all along the base, usually applied to a leaf segment
AlienIntroduced plant that has become established
Anastomosing(Of veins): joining up to form a network
AnnulusThe ring or line of thick-walled (indurated) cells on the sporangium that allows it to burst open when ripe (dehisc)
Antheridium; plural: antheridiaMale sex organ, on the underside of the prothallus, that produces sperm
ApogamousFerns that reproduce asexually: the new plants (sporophytes) grow directly from the prothallus, not from a fertilized egg
AppressedLying flat against
Archegonium; plural: archegoniaThe female sex organ containing the egg
AreoleArea enclosed by netted (anastomosing) veins
AscendingCurving upwards
AttenuateGradually tapering to a long thin point
AuricleEar-like lobe at the base of a leaf
AxilAngle between the main and side branches
AxillaryIn the axil
Axis; plural: axesThe primary or central part of of a plant or leaf to which the other parts are joined, eg the rachis or midrib
Basal cellsCells in the sporangium, between the annulus and the top of the stalk. The number of these is a diagnostic character in Polypodium
Basal sinusLowest sinus on a leaf
BasiscopicFacing towards the base (of frond or pinna)
BipinnatePinnate with the pinnae also pinnate (also 2-pinnate, twice-pinnate); the secondary divisions are called pinnules
Bipinnate-pinnatifidAs above, but with the pinnules divided again about half to three-quarters of the way to the midrib
BladeMain part of the leaf or frond, excluding the stipe
BulbilSmall bulb-like or bud-like body borne above the ground on a stem or leaf, which detaches to grow as a new plant - see Huperzia selago. (See also gemma)
CalcicoleA plant that prefers alkaline (base-rich) conditions ("lime-loving")
CalcifugeA plant that prefers acid (base-poor) conditions ("lime-hating")
CapsuleThe part of the sporangium within which the spores develop
Clathrate(Of scales): having a latticed appearance under a hand-lens - the result of dark cell walls
ConcolorousUniformly coloured
ConeBranch tips bearing modified spore-bearing leaves (sporophylls) compressed together so they appear distinct from the other leaves; also known as a strobilus. Found in Horsetails and Clubmosses
ConfluentRunning or merging together
Contiguous(Usually of margins of leaf segments): touching each other or running alongside
Cordate(Usually of the base of a frond or blade): heart-shaped
CoriaceousLeathery in texture
CostaMidrib of a pinna
CrenateHaving rounded teeth
CrozierThe young leaf forming a coil before it unfurls. (Often called a fiddlehead in the U.S.)
CuspidateNarrowing abruptly to a point
Decumbent(Usually of rhizomes): prostrate or flat to the ground but with the tip turned up
Decurrent(Of the frond or leaf-segment): having the base extend downwards along the axis
Dehiscence (verb: to dehisc)Opening of the sporangium to release the spores
DentateToothed, with the teeth pointing mostly outwards
DenticulateFinely dentate
DichotomousBranching in two
DimorphicHaving two forms. Usually applied to fertile and sterile leaves of some ferns, eg Thelypteris, Osmunda
DiploidWith two matching sets of chromosomes
DissectedDeeply divided
DistalFurthest away, usually referring to the part of leaf or leaf segment furthest way from the point of attachment
DistantWidely spaced, far apart
DivergentGrowing apart, spreading out
Dorsiventrally flattenedFlattened to give an upper and a lower surface
Entire(Of the margin of leaf): not toothed, lobed or divided
EphemeralLasting only a short time; (of indusium): quickly shed
EpiphyticGrowing on trees, using their bark or branches as support but not parasitic on them
EuphyllophytesThe group containing both ferns (monilophytes) and seed-bearing plants (spermatophytes)
Eutrophic(Of lakes, ponds, etc.): rich in nutrients
False indusiumAn indusium formed by the rolled-over margin of the leaf enclosing the sorus, as in Adiantum capillus-veneris
FamilyTaxonomical division comprised of a group of related genera
Fern alliesGroup of vascular plants traditionally thought to be closely related to ferns, based mainly on the spore-bearing characteristic. These comprise the families of horsetails (Equisetaceae), quillworts (Isoetaceae), clubmosses (Lycopodiaceae), whisk ferns (Psilotaceae) and spikemosses (Selaginellaceae). Recent research has shown quillworts, clubmosses and spikemosses to be much less closely related to ferns, while horsetails and whisk ferns are more closely related, in fact essentially part of the main fern grouping
Free(Of veins): not joined at the ends
FrondThe leaf of a fern, including the stipe
GametophyteThe sexual generation of the fern developing from the spore, generally a small flattish plant (see prothallus). The sex organs (archegonia and antheridia) develop on this, and the fertilization of the egg by the sperm (antherozoid) produces the gamete which develops into the recognizable fern plant (sporophyte)
Gemma; plural: gemmaeA bud or bulbil that detaches from the main plant and develops into a new plant, as in Huperzia selago
Genus, pl: generaTaxonomic division comprised of a group of related species
GlabrousHairless and scaleless
GlandAn organ that secretes a sticky and/or scented juice, usually on the surface of leaf or stem, appearing as a spot, a raised bump or the tip of a hair
GlandularHaving glands
GlaucousGreyish, blue-grey or whitish (often as a bloom on an otherwise green surface)
Globose; globularSpherical or nearly so
HaploidWith a single set of chromosomes. This is characteristic of the gametophyte stage
HeterosporousWith two types of spores: megaspores (female) and microspores (male), as in Isoetes and Selaginella
HexaploidWith six sets of chromosomes
HomosporousWith spores all of a single type, as in most ferns
HybridCross between two different taxa. Usually between species, but subspecies may hybridise (see Nothosubspecies), and occasionally hybrids between species belonging to different genera occur
ImbricateOverlapping, like roof tiles
IncisedCut deeply
Indurated cellsThe thickened cells of the sporangium making up the annulus
Indusium; plural: indusiaMembrane covering the sorus, not always present, and often shed at some stage in the development of the sorus. See also false indusium
InternodeThe part of the stem between nodes. Used of Equisetum
IntroducedA plant that was brought into the country (either deliberately or accidently) by man
LaminaThe leafy part of a frond, not including the midrib, rachis or stipe
LanceolateLance-shaped: narrow, pointed, slightly wider below the mid-point of the leaf
LatticedForming a mesh
LeafFrond; used here to include both the "leafy" part and the stipe or stem
Leaf-bladeThe "leafy" part of the frond excluding the stipe or stem
Leaf-segmentAny subdivision of a frond. See pinna, pinnule, pinnulet
LiguleSmall membrane at the base of the upper side of the leaf, found in Isoetes and Selaginella
LinearLong, narrow and parallel-sided or close to
LobeA clear division of a leaf or leaf segment but not so as to be completely cut to the midrib
LycophytesThe group comprising quillworts, clubmosses and spikemosses. Distinct from both euphyllophytes, the group that contains both seed plants (spermatophytes) and ferns (monilophytes)
MegasporangiumThe sporangium bearing megaspores, in heterosporous plants - Sealaginella and Isoetes
MegasporeThe female spores, usually relatively large, in heterosporous plants. These give rise to female gametophytes (archegonia)
MicronOne thousandth of a millimetre
MicrosporangiumThe sporangium bearing microspores, in heterosporous plants - Sealaginella and Isoetes
MicrosporeThe male spores, usually relatively small, in heterosporous plants. These give rise to male gametophytes (antheridia)
MidribCentral vein of a frond in simple fronds, or of a leaf-segment in divided fronds
MonilophytesThe group comprising all ferns, now known to include horsetails and whisk-ferns; a recently-coined term to distinguish them from spermatophytes (seed-bearing plants)
MonoleteHaving a single rectilinear mark. Used of spores. The mark derives from the way the spore was attached to the other spores in the sporangium. Monolete spores are generally approximately bean-shaped; see also Trilete
MorphotypeAn intermediate taxonomic division (not formally recognized), generally used to describe forms at around species level or narrower, where the differentiation is not fully understood (as in Dryopteris affinis)
MucronateTerminating abrubtly in a short point
NativeOccurring naturally, not introduced by man
NaturalizedAn introduced plant that has become established and propogates itself naturally
NodeThe point on a stem where leaves arise. Nodes are most clearly seen in horsetails
Nothosubspecies, often abbreviated to nothosubsp., nothossp. or n-subspHybrid where one or both parents is a subspecies (the term nothospecies is occasionally used to denote a hybrid between two species)
ObtuseAngle greater than 90°
Oligotrophic(Of lakes, ponds, etc.): poor in nutrients
OvateEgg-shaped (in two dimensions)
Paraphysis; plural: paraphysesSmall hairs, often branched, among sporangia; eg Polypodium cambricum
PatentAt right-angles
Peduncle(Of Clubmosses): the stalk of a cone
PeltateHaving the stalk attached in the centre
PersistentLasting a long time; (of indusium): remaining in place
PetioleThe stalk of a leaf; usually referred to as a stipe in ferns
Pinna; plural: pinnaePrimary division of a leaf. Pinnae are attached to the rachis by their midribs
Pinna segmentDivision of a pinna, whether cut entirely to the midrib or not
PinnateHaving the leaf divided once into distinct leaflets; like a double-sided comb (also 1-pinnate, once-pinnate). 2-pinnate = having the primary divisions are themselves pinnate (also bipinnate, twice-pinnate)
Pinnate-pinnatifidPinnate, with the pinnatifid pinnae (divided, but not all the way to the midrib)
PinnatifidHaving the leaf divided once into distinct divisions, but not cut all the way to the rachis, so not forming separate leaflets
PinnatisectAs pinnatifid but cut almost all the way to the rachis
PinnuleSecondary division of a leaf. Pinnules are disions of pinnae
Pinnule segmentDivision of a pinnule, whether cut entirely to the midrib or not
PinnuletTertiary division of a leaf. Pinnulets are divisions of pinnules
PolyploidWith more than two sets of chromosomes
ProcumbentLying flat along the ground
ProthallusThe gametophyte stage of the fern. This is the independent stage where sexual reproduction takes place. In most ferns, it is a small, flattish, often roughly heart-shaped body
ProximalClosest, usually referring to the part of leaf or leaf segment closest to the point of attachment
PteridophyteTraditional term encompassing both ferns and "fern allies"; the latter now known to be composed of some groups which are essentially ferns but look unlike them, and others which are not at all closely related. See Lycophytes, Monilophytes, Euphyllopytes
PubescentCovered in small fine hairs
Rachis (also rhachis); plural: rachides or rachisesThe section of midrib within the leafy part of the frond, ie above the stipe
ReceptacleThe part of the frond to which the sorus is attached; often raised slightly above the surface
ReflexedBent backwards or downwards
Reticulate(Usually of veins): forming a network
RhachisSee rachis
RhizomeStem of the fern plant, as opposed to the stem of an individual leaf which is called a stipe. In ferns, this is is often partially hidden, indistinct or partially underground. It may be creeping, as in Polypodium, or upright and highly visible as in tree-ferns
ScaleSmall, often semi-transparent outgrowth of the outer layer of cells (epidermis). Usually most frequent towards the lower part of the stipe. Must be at least two cells wide to qualify as a scale - if only one cell wide it's a hair. Dicksonia species, for example, have hairs instead of scales
ScariousThin, dry-looking, translucent, often whitish
SimpleNot divided. Applies to a whole leaf, as opposed to entire
SinusThe gap or indentation between teeth or lobes of frond
SorusA cluster of sporangia
SpeciesTaxonomic division generally used to describe those plants that will interbreed freely with each other and share a range of visual similarities. There is, however, no precise, universally agreed definition
SpermatophytesSeed-bearing plants
SpinoseWith spines
SpinuloseWith small spines
Sporangium; plural: sporangiaThe spore case; capsule containing spores. A group of sporangia make up a sorus
SporeThe minute, single-celled body which develops in the sporangium. When released it germinates and develops into the gametophyte
SporelingTiny fern plant still attached to the gametophyte from which it has developed
SporocarpA globose structure that contains the sporangia in Pilularia
SporophyllFertile leaf that carries the sporangia in clubmosses
SporophyteThe generation of the fern that produces the spores. This is the main visible plant that is normally thought of as the actual fern. See gametophyte
StipeStalk of the leaf, ie the part of the midrib below the leafy part or blade
StolonRunner from the main stem, producing a new plant that roots independently
Strobilus; plural: strobiliThe cone. Branch tips bearing modified spore-bearing leaves (sporophylls) compressed together so they appear distinct from the other leaves. Found in Horsetails and Clubmosses
Subspecies, often abbreviated to spp. or subspSubdivision of a species
Taxon; plural: taxaAny members of a specific taxonomic grouping, eg species, genus, etc. So one may refer to the Asplenium trichomanes and Asplenium ruta-muraria taxa (species); Dryopteris and Polystichum taxa (genus); or the Lycopodiacae and Selaginellaceae taxa (family)
TerminalAt the tip
TerrestrialGrowing on the ground
TetraploidWith four matching sets of chromosomes
ToothSmall lobe
TransverseAt right angles; cross-ways
TrileteHaving a distinct Y-shaped mark. Used of spores. The mark derives from the way the spore was attached to the other spores in the sporangium; see also Monolete
TripinnatePinnate with the pinnae and pinnules also pinnate (also 3-pinnate, thrice-pinnate)
TriploidWith three matching sets of chromosomes
Ultimate segmentThe final, smallest divisions of a leaf
Variety, often abbreviated to varSubdivision of species, but less well-defined that a subspecies
VeinStrands of vascular tissue, normally visible in leaves
VenationThe pattern formed by the veins in the leaf
VerrucoseCovered in small warts
Print Friendly, PDF & Email

The website for people who like ferns

The British Pteridological Society