Biodiversity

Australian Biological Resources Study

Flora of Australia Glossary

Lichens

D.J.Galloway

A

 

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.

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.

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.

B

 

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.

C

 

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.

D

 

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.

E

 

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.

F

 

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).

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.

G

 

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.

H

 

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.

I

 

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.

L

 

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.

M

 

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.

N

 

nigrescent: turning black.

nodular: with lumps or knots.

O

 

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.

P

 

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.

R

 

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.

S

 

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.

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.

T

 

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.

U

 

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.

V

 

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.

Z

 

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

Lichens

Key

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