Lichen Glossary


This general Glossary contains terms likely to be used in the volumes of the Flora of Australia dealing with the lichens (Volumes 54-58). Specialised terms that are crucial to the understanding of the account of an individual family or genus, but not of wide application, will be defined as appropriate in the relevant volumes.

As far as possible the definitions provided here conform with those used for vascular plants, but there are some instances where the meanings differ and long-standing practice is accepted.

It is the policy of the Flora Editorial Committee to keep the use of technical terms to a minimum so as to make it easy for the reader to use the Flora without constant reference to the Glossary. Words explained accurately, for botanical purposes, in The Macquarie Dictionary have generally not been included in the Glossary unless much more widely used in English in a different sense.


This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced by any process without prior written permission from Australian Biological Resources Study. Requests and inquiries concerning reproduction and rights should be addressed in the first instance to the Executive Editor - Flora. These pages may not be displayed on, or downloaded to, any other server without the express permission of ABRS.

| A | B | C | D | E | F | G | H | I-K | L | M | N-O | P-Q | R | S | T | U-Z |


accessory: of a chemical, sometimes present, sometimes not present. Often expressed as ±, e.g. ±protocetraric acid.

acicular: needle-shaped.

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.

aggregated: clustered.

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.

articulate: jointed.

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.

capillary: hair-like.

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.

clavate: club-shaped.

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.

coriaceous: leathery.

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.

cucullate: hooded.

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.

dactyloid: finger-shaped.

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 x10 lens).

fastigiate: having parallel, massed upright branches (of lichen cortex, made up of parallel hyphae at right angles to axis of thallus).

faveolate: honey-combed.

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.

filamentous: thread-like.

filiform: very narrow in section.

fimbriate: fringed.

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.

flabellate: fan-shaped.

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.

foliose: leaf-like.

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 x10 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.


imbricate: overlapping.

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.

ligulate: strap-shaped.

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.

longitudinal: lengthways.

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.

membranaceous: parchment-like.

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.

pedicellate: stalked.

pellucid: more or less transparent.

peltate: shield-like.

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.

photophilous: light-loving.

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.

punctiform: dot-like.

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.

pyriform: pear-shaped.


radiating: spreading from a central point.

reniform: kidney-shaped.

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).

rimose: cracked.

rosette: a circular cluster, e.g. of lobes.

rugose: wrinkled.

rugulose: delicately or minutely wrinkled.


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.

squamiform: scale-like.

squamule: a scale or foliole, usually corticate on both sides.

squamulose: scaly, with squamules.

squarrose: branching at right angles, as in rhizines.

stellate: star-shaped.

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.


umbilicate: navel-like.

unciform: hook-shaped.

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.

verruciform: wart-like.

verrucose: warted.

zonate: ringed (especially at thallus margins) in circular lines forming pale and dark zones.


This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced by any process without prior written permission from Australian Biological Resources Study. Requests and inquiries concerning reproduction and rights should be addressed in the first instance to the Executive Editor - Flora. These pages may not be displayed on, or downloaded to, any other server without the express permission of ABRS.


Last updated on 13 May 1999.

Australian Biological Resources Study