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accessory: of a chemical, sometimes present, sometimes not present. Often expressed as ±, e.g. ±protocetraric acid.
acute: sharply pointed at the apex.
adnate: thallus attached to the substratum; can usually be removed intact (when wet) from the substratum with a knife; herbarium specimens often have rock attached.
loosely adnate: thallus loosely attached to nearly free growing; easily removed from the substratum by hand and rarely collected with substrate.
moderately adnate: more loose than an adnate thallus, tighter than a loose thallus, usually removed intact with the aid of a knife.
tightly adnate: thallus tightly attached to the substratum; removal of thallus with a knife results in fragmentation; herbarium specimens always with rock attached.
very tightly adnate: thallus subcrustose; removal of thallus with a knife extremely difficult unless thallus has been wetted.
amyloid: staining blue, blue-purple, blue-black or reddish in iodine.
anamorph: an asexual stage or morph characterised by the production of conidia.
anastomosing: joining up, running into each other — used of branched paraphyses which form a network.
anisotomic: unequal branching, with a distinct main axis and smaller side branches.
annular: arranged in or forming a ring.
annulation: a ring-like, often pigmented cortical zone, usually more or less blackened, especially of branches of Neuropogon.
anticlinal: of the orientation of hyphae in a tissue, perpendicular to the surface.
apical: situated at the tip.
apiculate: ending in a short, slender projection.
apothecium: a type of ascoma; a more or less flat, disc-like fruit, either round (e.g. Lecidea) or elongate (e.g. Opegrapha) in which the hymenium is exposed at maturity. pl. apothecia.
appressed: closely and flatly pressed against a surface.
arachnoid: cobweb-like in texture or pattern.
arcuate: bent, curved or arched like a bow.
areola: a small area, rounded, more or less polygonal or angular, delimited by cracks or chinks in thallus surface. pl. areolae.
areolate: island-like, sharply divided into areolae by separating cracks.
ascending: directed upwards at a rather narrow angle, curving upwards.
ascogenous: ascus-producing or -supporting.
ascogonium: a cell or group of cells in Ascomycotina fertilised by a sexual process. pl. ascogonia.
ascohymenial: Ascomycotina having asci and paraphyses arranged as a hymenium, as in pyrenomycetes and discomycetes.
ascolocular: Ascomycotina having asci in cavities, as in loculoascomycetes.
ascoma: the ascus-bearing organ of an ascomycete. pl. ascomata.
Ascomycotina (Ascomycetes): a class of fungi in which spores are developed in asci.
ascospore: a spore produced in an ascus.
ascus: the sac-like cell of the perfect state of an ascomycete, in which ascospores (usually 8) are produced. pl. asci.
ascyphous: without a cup — especially in Cladonia.
aspicilioid: of lecanorine apothecia, more or less immersed in the thallus, at least when young.
attenuate: tapering gradually.
autonomous: separate, independent.
axis: a main stem, or central longitudinal support.
bacilliform: rod-like, usually more than 3 times as long as wide. cf. cylindrical.
basidioma: the basidium-bearing organ of Basidiomycotina. pl. basidiomata.
Basidiomycotina (Basidiomycetes): a class of fungi in which spores develop on basidia.
basidiospore: the spores from a basidium.
basidium: the organ in Basidiomycotina which, after karyogamy and meiosis, bears the basidiospores. pl. basidia.
biatorine: of lichen apothecia, of lecideine type, pale or more or less coloured, soft in consistency, and generally strongly convex.
bicornute: bearing, or terminating in, two small horns.
bifusiform: fusiform but constricted in the middle.
biseriate: of spores in an ascus, arranged in two rows.
bitunicate: of an ascus, with two distinct walls, a thin inextensible outer wall and a thick extensible inner wall.
blastidia: small subsidiary locules in a thick-walled spore — especially in Physciaceae.
bullate: of a surface, blistered or puckered.
bullate-areolate: with convex (blister-like) areolae.
campylidia: structures to 1 mm tall shaped rather like a cat’s ear, on the upper surface of foliicolous lichens, possibly acting as a splash-cup mechanism for dispersal of vegetative fragments produced on the inner surface.
canaliculate: with a longitudinal groove or channel.
capitate: having an obvious head, swollen at apex.
carbonaceous: black, opaque.
cartilaginous: firm and tough but readily bent, gristly.
centrum: the perithecial chamber enclosed by the exciple
cephalodium: a delimited region within, or a warty, squamulose or foliose structure on the surface of, a lichen thallus containing a photobiont different from that characteristic of the rest of the thallus. Generally cephalodia contain cyanobacteria (e.g., Nostoc) while the rest of the thallus has a green photobiont (e.g., Trebouxia). Nostoc heterocysts in cephalodia fix atmospheric nitrogen. Genera containing cephalodia include: Coccotrema, Lobaria, Placopsis, Psoroma, Psoromidium, Pseudocyphellaria, Solorina, Stereocaulon and Sticta. pl. cephalodia.
cerebriform: convoluted, brain-like.
chlorophycean: having the grass-green colour and other essential characteristics of the Division Chlorophyta.
chondroid: tough, cartilaginous.
cilium: a short, eyelash-like hair, usually marginal on thallus or on fruits. pl. cilia.
coccoid: of cells, globose or subglobose, usually free from one another and often grouped within a gelatinous matrix
columella: a central shaft of hyphae within an ascoma.
complicate: folded, bent upon itself.
compound: of a perithecium, having an involucrellum.
concave: hollowed out, basin-like.
concentric: arranged around a common centre.
concolorous: of one or the same colour.
confluent: blending or running together.
conglutinate: of hyphae, especially paraphyses, glued or stuck together.
conidiogenous: producing conidia.
conidioma: a multi-hyphal, conidium-bearing structure. pl. conidiomata. cf. pycnidium.
conidiophore: a simple or branched hypha-bearing cell from which conidia are produced.
conidium: an asexual spore produced in a pycnidial conidioma. pl. conidia.
constricted: of lobes, of varying width.
contiguous: touching but not fused.
convex: equally rounded, broadly obtuse.
convolute: of lobes, the upper surface strongly convex and the lower surface strongly concave.
coralloid: usually of isidia, coral-like, often brittle.
cortex: the outermost layer of the thallus which, if present, consists of compacted hyphae which may appear either fibrous or cellular.
corticate: having a cortex.
crenate: scalloped with small, rounded notches or teeth, the sinus acute.
crenulate: finely crenate.
crisped: of a margin, crumpled or thrown into waves.
crustose: crust-like, used for lichens having a thallus stretched over and firmly fixed to the substratum by the whole of the lower surface, such thalli generally lack rhizines and a lower cortex.
cryptolecanorine: of an ascoma, with a reduced or inapparent thalline margin.
cuneate: wedge-shaped, thinner at one end than the other.
cyanobacteria: prokaryotic organisms without organized chloroplasts but having chlorophyll a and oxygen-evolving photosynthesis; capable of fixing nitrogen in heterocysts; occurring in lichens both as primary photobionts and as internal or external cephalodia; still commonly called blue-green algae.
cyanobiont: the cyanobacterial photosynthetic partner in a lichen symbiosis.
cyanophycophilous: containing cyanobacteria as the primary photobiont.
cylindrical: rod-like, usually 2–3 times as long as wide. cf. bacilliform.
cyphella: a break in the lower cortex of a lichen thallus which is rounded or ovate or effigurate and in section appears as an inverted cup-like structure lined with a layer of loosely connected frequently globular cells distinct from the medulla, characteristic of the genus Sticta. pl. cyphellae.
dactyl: a hollow, nodular to cylindrical protuberance, somewhat resembling a swollen isidium, bounded by a cortex, often opening at the apex to expose the medulla.
decorticate: lacking a cortex.
decumbent: resting on a substratum, with the end turned up.
deflexed: bent sharply downwards.
delimited: having a distinct restricting edge or margin.
dendroid: irregularly branched, tree-like in form but not in size.
determinate: having a distinct, defined form.
diaspore: any propagule, sexual or asexual.
dichotomous: branching, often successively into two more or less equal branches.
diffract: cracked into small areas, areolate.
diffuse: widely or loosely spreading, with no distinct margin.
digitate: branching from the axis or stalk like the fingers of a hand.
dimidiate: of an involucrellum, covering only the upper half of a perithecium.
dimorphic: having two forms.
disc: a round, plate-like or curved spore-producing part of the fruiting body, the upper surface of an ascoma.
discoid: flat and circular, disc-like.
disjunct: of a population of a species, widely separated geographically or ecologically from other populations of the same species.
divaricate: widely spreading.
divergent: spreading away from one another, usually at a rather wide angle.
dorsal: the back or upper surface, the surface facing away from the axis; of a thallus, the ‘back’, i.e. the side facing away from the substratum. cf. ventral.
dorsiventral: with distinct upper and lower surfaces.
eciliate: without cilia.
ecorticate: without a cortex.
effigurate: of pseudocyphellae, particularly on the upper surface, having a definite form or figure.
effuse: stretched out flat especially as a film-like growth.
ellipsoidal: oval in outline and three-dimensional.
elliptic: oval in outline and flat.
endemic: occurring naturally only in a single geographic area.
endolithic: immersed in rock.
endophloeodal: immersed in bark.
endosubstratic: growing within the substratum.
entire: not dissected or lobed.
epicortex: a thin, homogeneous polysaccharide layer over the surface of the cellular cortex, which may have regular pores or breaks (using the scanning electron microscope).
epicorticate: covered by epicortex; of apices of isidia, eroding or breaking open very easily and often appearing hollow or erumpent, or becoming pustulate.
epihymenium: uppermost (often pigmented) layer of hymenium, above asci.
epilithic: growing on surface of rocks.
epiphyllous: growing on the surface (usually upper) of leaves, the mycobiont not penetrating the leaf surface.
epiphyte: a plant growing on another but not organically connected with it.
epipsamma: a granular zone (usually pigmented) permeating upper parts of hymenium but more or less distinct from epithecium, especially in Rhizocarpon.
episporium: the thin outer covering of a spore. cf. exosporium.
epithecium: the upper part (3–15 µm) of the hymenium where this differs in appearance from the lower part; the layer of uppermost parts of the paraphyses overtopping the asci, often pigmented.
erumpent: bursting through surface; of isidia, apices bursting open.
esorediate: without soredia.
eutrophicated: nutrient-enriched (correctly of water).
evanescent: short-lived, soon disappearing.
excavate: of a perithecial axis, deeply concave.
exciple: of an apothecium, tissue or tissues characteristic of the margins adjacent to the hymenium and hypothecium. Proper exciple (excipulum proprium) — tissue at the margin of an apothecium adjacent to the hymenium and hypothecium and inside the thalline exciple when present, without photobiont cells. Thalline exciple (excipulum thallinum) — tissue at the margin of an apothecium external to proper exciple and having a structure similar to that of the vegetative thallus with photobiont cells included in it.
excluded: shut out — applied to proper or thalline margin of a discocarp when the disc swells, causing the margin to be obliterated.
exfoliating: losing outer cortex through peeling or cracking.
exosporium: thin or thick outer covering of a spore (especially in Pannariaceae). cf. episporium.
fabiform: kidney-bean shaped.
fasciculate: of branching or growth form, many branches arising from one point like a bundle of sticks; of rhizines, many simple rhizines arising from one point or region.
farinose: of soredia, like grains of flour (use ×10 lens).
fastigiate: having parallel, massed upright branches (of lichen cortex, made up of parallel hyphae at right angles to axis of thallus).
fenestrate: with open areas or slits.
fibrous: of a lichen cortex, consisting of loosely woven distinct hyphae parallel with the long axis of the thallus.
filiform: very narrow in section.
fissitunicate: a type of bitunicate ascus discharge where the outer wall ruptures at the apex and slips down towards the base, and the inner wall swells.
fissured: cracked, split.
flaccid: limp, flabby.
flexuose: having a wavy or zig-zag form.
floccose: covered with soft woolly trichomes that are entangled, tufted, and tend to rub off and adhere in small masses or pills.
foliole: a small, dorsiventral, leaf-like appendage.
friable: readily powdered, crumbling.
fruticose: shrub-like in habit.
furcate: forked, as in rhizines with two long, terminal branches.
fusiform: spindle-like, narrower at the ends than in the middle.
gelatinous: rubbery, jelly-like.
geniculate: bent, angled, bent like a knee, often with a subtending spur.
glabrous: without an indumentum.
glaucous: having a bluish grey bloom.
globose: more or less spherical.
glomerule: a very dense cluster. adj. glomerulate.
goniocyst: discrete, more or less globular structures c. 12–40 µm diam., ecorticate granules consisting of photobiont cells intertwined and surrounded by short-celled hyphae never protected by an amorphous covering layer (in Micarea).
granular: like grains of sugar (use ×10 lens).
granule: a grain.
guttulate: of spores, having one or more oil droplets inside.
gyrose: of an apothecial disc, concentrically folded or ridged, especially in Pannaria, Psoroma, Umbilicaria.
halonate: of the outer layer of spores, surrounded by a transparent coat.
hamathecium: a neutral term for all kinds of hyphae or other tissues between asci, or projecting into the locule or ostiole of an ascoma.
hapteron: an aerial organ of attachment of some fruticose lichens (Alectoria, Bryoria, Usnea) formed by a secondary branch which becomes attached to the substratum; pl. haptera.
haustorium: a special hyphal branch, especially one within a living cell of the host, for absorption of nutrients; pl. haustoria.
hemiangiocarpic: of a sporocarp, opening before quite mature.
heteromerous: having mycobiont and photobiont components in well-defined layers, with the photobiont in a more or less distinct zone between the upper cortex and the medulla.
hirsute: having a covering of long, coarse hairs.
holdfast: a process from the base of the thallus for attachment, often disc-like.
homoiomerous: having mycobiont and photobiont components intermixed throughout thallus, not layered.
humicolous: growing on soil.
hyaline: colourless, translucent.
hymenium: the spore-bearing layer of a fruiting body, containing asci, spores and paraphyses.
hypha: a fungal filament. pl. hyphae.
hyphophores: simple or complex whip-like outgrowths on the upper surface of the thallus, especially of foliicolous lichens, possibly a mechanism for the dispersal of vegetative propagules produced by strands or hyphae protruding from the tip.
hypophloedal: immersed in bark.
hypothallus: a layer of hyphae, often dense and more or less woolly or spongy, without photobiont, at margins or below thallus, often black or dark brown in Anzia, Pannoparmelia and Pannariaceae.
hypothecium: fungal tissue between the hymenium and the exciple (if present), often pigmented, also known as the subhymenium.
immarginate: without a margin or well-defined edge.
immersed: embedded in the substratum.
imperforate: of an apothecial disc, not perforated.
impressed: pressed in.
incised: cut deeply, sharply and often irregularly (an intermediate condition between toothed and lobed).
indeterminate: with margins not well defined.
indigenous: natural to a country or region, native.
indumentum: a covering of surface outgrowths such as hairs.
inflexed: turned or bent abruptly inwards (inrolled), e.g. the margin of a fruit.
innate: sunken, immersed.
interthecial: of hyphae, lying between asci. See hamathecium.
intermediate-type: of lichenan in Parmeliaceae, intermediate between Cetraria-type lichenan and Xanthoparmelia-type lichenan.
involucrellum: tissue forming the upper part of a perithecium, distinct from and surrounding the exciple.
involute: rolled upwards.
isabelline: dirty brownish grey, yellowish or tawny.
isidiate: with isidia.
isidioid: having the form of an isidium.
isidioid soredia: soredia which become corticate in part.
isidium: a corticate, photobiont-containing protuberance or outgrowth of the cortex which may be warty, cylindrical, clavate, coralloid, simple or branched. pl. isidia.
isotomic: branching into two or more branches all of equal diameter.
labriform: lip-shaped (especially of soralia).
lacerate: cut, torn or ragged.
lacinia: a narrow, linear-elongate lobe of a foliose lichen, often arising from the primary lobes. pl. laciniae.
laciniate: deeply, usually irregularly divided into narrow, more or less pointed segments; of lobes, developing laciniae or being lacinia-shaped; of margins, deeply, usually irregularly, divided into narrow, ±pointed segments.
lacuna: a hole, depression, gap. pl. lacunae.
lamina: a thin, flat organ or part, usually main upper surface of thallus.
laminal: on or pertaining to upper surface.
lateral: at or near edge, especially side or secondary branches.
lax: loosely arranged.
lecanorine: of an apothecium, with a thalline exciple, photobiont in margin.
lecideine: of an apothecium, with a proper exciple, without photobiont in margin.
lenticular: having the shape of a more or less circular biconvex lens.
leprose: having the surface dissolved into soredia, loose, powdery, without any cortex.
lichenicolous: growing on lichens.
lignicolous: growing on decorticated wood.
limiting: surrounding or setting a limit to — often used of a surrounding prothallus.
linear: very narrow, with parallel margins.
lirella: an ascoma with a long, narrow disc often branching or more or less stellate. e.g. Graphis, Phaeographis, etc. pl. lirellae.
lobe: a recognisable but not separated division, especially when rounded.
lobulate: having small lobes.
lobule: a small lobe (often marginal or laminal).
locule: cell or cavity.
lumen: the interior of a cell. pl. lumina.
macrolichen: larger lichens of squamulose, foliose or fruticose habit.
maculate: spotted or blotched, often caused by discontinuities in photobiont zone below upper cortex.
marginate: with a well-defined edge or margin.
matt: with a dull surface.
mazaedium: a spore mass formed in fruits of Caliciales in which spores, generally with sterile elements, become free from the ascus as a dry, loose, often dark, powdery mass on the fruiting surface.
medulla: a loosely arranged layer of hyphae below the upper cortex and photobiont zone.
membranous: thin, more or less pliant, like a membrane.
microlichen: a crustose lichen, usually small.
microphylline: with minute leaflets or leafy scales.
mischoblastiomorph: a specialised thick-walled spore found in Rinodina.
moniliform: like a string of beads.
monomorphic: having a single structural form.
monophyllous: consisting of a single lobe, often undulate or folded.
monopodial: of growth, with a persistent terminal growing point, producing lateral organs successively.
morphodeme: a group of individuals in a taxon that is morphologically differentiated from the rest of the taxon by a characteristic of undetermined or no taxonomic significance.
multiseptate: with many septa.
muriform: like a wall, having many transverse and longitudinal septa. cf. submuriform.
muscicolous: growing on mosses.
mycobiont: the fungal component of a lichen.
nigrescent: turning black.
nodular: with lumps or knots.
obligate: restricted to a particular host, substratum or mode of nutrition.
oblique: with sides unequal.
oblong: having the form of a rectangle of greater length than width.
obovate: inversely ovate (narrowest at base).
obsolete: rudimentary or absent.
obtuse: rounded or blunt at the apex.
ochraceous: of a dull, yellow colour.
ocular chamber: a cavity lying on the longitudinal axis of an ascus and penetrating into the thickened apical dome of the ascus from the ascal sac.
opaque: dull, not translucent.
orbicular: circular or nearly so, more or less flat.
oriented: turned in one direction.
ostiole: an opening or pore, in fungi and lichens, a pore at the apex of a perithecium through which spores are extruded. adj. ostiolar.
oval: broadly elliptic, narrowing somewhat from middle to rounded ends.
ovate: egg-shaped in outline but flat (wider at base).
ovoid: egg-shaped, three-dimensional.
palisade plectenchyma: a tissue consisting of short hyphae emerging from the algal layer, becoming erect, and packing together to form a ±anticlinally oriented layer with sizeable interstices between the cells.
palmate: radiately lobed or divided.
papilla: minute, pimple-like process. pl. papillae.
papillate: with papillae.
paraphysis: a sterile, upright, basally attached fungal filament in a hymenium, growing between asci. pl. paraphyses.
paraphysoid network: a network of anastomosing fungal hyphae surrounding asci in some bitunicate lichens and taking the place of paraphyses.
paraplectenchyma: tissue consisting of isodiametric cells.
parasite: an organism living on or in, and obtaining its food from, its host, another living organism.
parasymbiont: an organism symbiotic with a pre-existing symbiosis (e.g., a lichenicolous fungus) not damaging its host.
parathecium: of apothecia, the outside hyphal layer.
pellucid: more or less transparent.
pendulous: hanging down from a support.
periclinal: curved in the direction of, or parallel to, the surface or the circumference.
periphysis: a hair-like projection inside the ostiole of a perithecium or pycnidial conidioma. pl. periphyses.
periphysoid: short, interascal filaments growing down from the top of a perithecium.
perithecium: a type of ascoma, the more or less globular or flask-like fruiting body of Pyrenomycetes and angiocarpic lichens, opening by a pore at top. pl. perithecia.
phialides: conidiogenous cells producing conidia in basipetal succession through one or several openings.
photobiont: the photosynthetic partner in a lichen symbiosis, either a green alga or a member of the cyanobacteria.
photosymbiodeme: either of one or two morphologically distinct structures formed by the interaction of a single mycobiont with two different photobionts.
phycobiont: the green algal photosynthetic partner in a lichen symbiosis.
phyllidium: a small, corticate, scale-like, dorsiventral structure developed at the margins or on the upper surface of a thallus, usually attached by a narrow stalk. pl. phyllidia.
phyllocladium: a small, corticate thalline structure, granular, verrucose, coralloid, squamiform, digitate, or peltate, containing a green photobiont (in Argopsis and Stereocaulon). pl. phyllocladia.
placodioid: crustose at the centre but lobed and plicate at the circumference.
placodiomorph: a 2-celled spore with a thickened septum which may or may not have a pore. cf. polarilocular.
plectenchyma: a thick tissue formed by hyphae becoming twisted and fused together.
plicate: folded into pleats.
podetium: a lichenised, stem-like portion (stipe, or discopodium) bearing the hymenial discs and sometimes conidiomata in a fruticose apothecium (especially in Cladonia).
polarilocular: of lichen ascospores, two-celled, the two lumina separated by a thick septum through which a narrow canal passes. cf. placodiomorph.
polymorphic: having several or many morphological variants.
polyphyllous: of a foliose thallus, divided into many lobes.
polytomic: dividing into many branches usually at one node.
pore: a small opening.
primary lobe: initial lobes forming thallus.
primary species: in lichens, a species reproducing by sexual means. cf. secondary species.
proliferating: producing offshoots or outgrowths, successively developing new parts.
propagule: a thallus fragment capable of propagating the lichen (i.e., isidium, phyllidium, phyllocladium, soredium).
proper exciple: see exciple.
prosoplectenchyma: tissue consisting of cells with thickened walls and longish lumina and in which hyphal elements are recognisable as hyphae.
prothallus: a weft of fungal hyphae (white, reddish or blue-black) at the margin of the thallus, lacking photobiont, often projecting beyond the thallus onto the substratum.
pruina: a frost-like or flour-like surface covering, usually crystalline.
pruinose: surface covered with pruina (especially of apothecia).
pseudocyphella: a minute opening (round, elongate, effigurate) in the cortex exposing medullary hyphae (sometimes pigmented) but lacking specialised cells surrounding the cavity. pl. pseudocyphellae.
pseudoisidium: an elongate soredium which has become partially corticate and resembles an isidium but has the same origin as a soredium. pl. pseudoisidia.
pseudolobate: having the appearance of a lobate thallus due to the presence of radiating furrows.
pseudostroma: a stroma in which fungal cells and remnants of host tissue are mixed. pl. pseudostromata.
pseudothalline: (of a true exciple) concolorous with the thallus rather than with the disc.
pubescent: having a somewhat dense cover of short, weak, soft hairs.
pulvinate: in cushions.
pustulate-isidiate: with isidia which become pustulate.
pustulate-sorediate: developing pustules which become sorediate.
pustule: a pimple or blister-like swelling, hollow within, often eroding. adj. pustulate.
pycnidium: a small, globose or flask-like conidioma in which conidia develop (= pycnidial conidioma). pl. pycnidia (= pycnidial conidiomata). cf. conidioma.
pyrenocarpous: having a perithecioid ascoma, e.g. Verrucaria.
radiating: spreading from a central point.
resupinate: bent backwards or reversed by the twisting of the stalk.
reticulum: a network. adj. reticulate.
revolute: of a margin, rolled downwards; of lobes, weakly convolute, the upper surface weakly convex, the lower surface canaliculate.
rhizine: an organ of attachment, consisting of clustered hyphae, developing from the lower cortex (especially in Parmeliaceae).
rhizohyphae: organs of attachment, consisting of clustered hyphae, developing from the lower medulla, usually black, bluish or whitish (especially in Pannariaceae).
rosette: a circular cluster, e.g. of lobes.
rugulose: delicately or minutely wrinkled.
saccate: sac- or bag-like.
sac: a pouch-like structure.
saxicolous: growing on rocks or stones.
scabrous: rough to the touch with short, hard emergences or hairs. dim. scabrid.
schizidium: propagule formed from upper layers of thallus splitting off as scale-like segments from main lobes. pl. schizidia
scrobiculate: coarsely pitted, faveolate.
scyphiferous: bearing scyphi (cups), used especially when apices are expanded to form cups, e.g. Cladonia fimbriata.
scyphus: an expanded, cup-like structure often terminating a podetium.
secondary metabolite: natural product of restricted taxonomic distribution with no obvious metabolic function.
secondary species: in lichens, a taxon reproducing mainly, or only, by vegetative means, derived from extinct or extant species reproducing mainly, or only, by sexual means. cf. primary species.
septate: divided by cross walls.
septum: a cross wall. pl. septa.
seriate: arranged in rows.
sessile: not stalked, attached directly to the thallus surface (usually of apothecia).
sigmoid: curved like the letter ‘S’.
simple: not divided into several more or less similar parts, contrasted with compound.
sinuous: having rounded angles, wavy (of a margin).
sinus: notch, often between two lobes or segments.
soralium: a decorticate area on a lichen thallus where soredia are produced. pl. soralia.
sorediate: with soredia.
soredium: a decorticate structure consisting of photobiont cells and fungal hyphae, having the appearance of a powdery granule and capable of reproducing a lichen vegetatively. pl. soredia.
spathulate: spoon-shaped, broad at the tip and narrowed towards the base.
spongiostratum: spongy hypothallus, usually brown, dark brown-black or black, found in Anzia and Pannoparmelia. Can be continuous or discontinuous.
spore: a general term for a reproductive structure in fungi, bacteria and cryptogams, often 1-celled; the analogue of seeds in flowering plants.
sporocarp: a spore-producing organ; fruiting body.
squamule: a scale or foliole, usually corticate on both sides.
squamulose: scaly, with squamules.
squarrose: branching at right angles, as in rhizines.
stria: a fine, longitudinal line or minute ridge. pl. striae. adj. striate.
stroma: a mass or matrix of vegetative hyphae (usually black) with or without tissue of the host or substrate, sometimes Sclerotium-like in form, in or on which spores are produced, often covering a group of several ascocarps. pl. stromata.
sub-: a prefix meaning somewhat, slightly or not quite, e.g. subpedicellate.
subepilithic: of a crustose thallus, intermediate between endolithic and epilithic.
sublageniform: of conidia, short and rod-shaped with a swelling at one end, giving the conidium a ±elongated, flask-shaped appearance.
submuriform: of ascospores, having both transverse and longitudinal septa, but in which not more than 15 cells may be seen. cf. muriform.
subsorediate: with granules (as in soredia), but which are partly corticate.
substratum: the underlying layer, or base to which a lichen is fixed.
subulate: tapering from a wide base to a sharp apex, more or less circular in cross section, awl-shaped.
superficial: on the surface.
symbiont: an organism that is associated with another in a mutually beneficial relationship.
symbiosis: the living together of unlike organisms in a close, long-lasting association.
sympodial: of growth, without a single, persistent growing point; changing direction by frequent replacement of the growing apex by a lateral growing point below it.
syncorticate: covered by upper cortex; of apices of isidia, entire, and shiny or blackened.
tartareous: having a thick, rough, crumbling surface.
terete: cylindrical or nearly so, circular in transverse section.
terminal: borne at the end.
thalline exciple: see exciple.
thallus: the vegetative part of a lichen, a more or less undifferentiated plant body.
thelotremoid: especially of fruits, having the appearance of Thelotrema.
tholus: a thickened inner part of the ascus wall in the ascus apex.
tomentose: densely covered with matted short hairs.
torus: a thickening or swelling around septa in certain thick-walled spores in Rinodina.
translucent: more or less transparent.
transverse: across the width.
trichotomous: branching almost equally in three parts.
truncate: with an abruptly transverse end, as if cut off.
tubercle: a small, wart-like process.
tuberculate: covered with tubercles.
tufted: of rhizines, a simple rhizine densely fasciculate at the tip.
uniseriate: of spores in an ascus, in one row.
unitunicate: of an ascus which has no inner wall, with one layer, the wall layers not splitting apart at discharge.
urceolate: cup-shaped, urn-shaped.
vein: a strand of conducting or strengthening tissue. e.g. Peltigera.
ventral: front, or lower surface; of a thallus, facing towards the substratum. cf. dorsal.
zonate: ringed (especially at thallus margins) in circular lines forming pale and dark zones.