The Lichen Color Chart shows the variability in lichen colors.
Click on photos for larger version.
Scale: Bar=1mm unless noted
Habitat refers to ecosystem where the lichen can be found.
Substrate refers to the surface where the lichen can be found. Many lichens have a preferred substrate such as calcerous rock or conifer bark.
The outer "skin" of lichens, generally smooth, often glossy, composed of closely packed fungal hyphae.
The interior layer of most lichens, composed mainly of fungal hyphae. See photos above.
Growth FormGrowth forms are the general macroscopic appearance of a lichen.
Fruticose is a 3-dimensional growth form not differentiated into upper an lower surfaces, including pendulous and stringy, upright, or bushy, or with a 2-part thallus of primary squamules and upright stalks.
Foliose is a "leaf-like" growth form with dorsiventral lobes that is usually loosely to tightly appressed, 2-dimensional or weakly 3-D, and usually with a cortex on upper and lower surfaces.
A crust-like growth form of lichens that is closely applied to the substrate, like paint, generally attached by all of the lower surface and lacking a lower cortex and rhizines. See many examples of crustose lichens at the Oregon Digital lichen photo library at https://oregondigital.org/sets/lichens-pnw.
Lobes growing pressed closely to substrate.
Melanohalea multispora - Habit
Growth forms that are strongly three dimensional either by flattened branches or lobes, but without regard to whether the lobes have distinguishable upper and lower surfaces. Examples include Cetraria orbata, Platismatia glauca, Ramalina farinacea, and Evernia prunastri. "Strappy" branches are elongate and flattened, as in Ramalina farinacea and Evernia pruinastri. "Fluffy foliose" includes 3-dimensional foliose forms such as Cetraria orbata and Platismatia glauca. Using the "fluffy foliose or strappy" character avoids the technical distinction between fruticose forms like Ramalina farinacea and dorsiventrally differentiated (i.e. foliose) but otherwise extremely similar growth forms, such as Evernia prunastri.
Ramalina farinacea - Habit
Hairlike, pendant from the substrate or in tufts when small.
Hairlike, growing erect or suberect from the substrate.
Hairlike, growing appressed to the substrate.
Growth form of basal squamules and erect stalks.
Cladonia coniocraea - Habit
Growth form with cylindrical or roundish stalks, the tips pointed, rounded, or with cups. A podetia is the upright, hollow stalk that forms the secondary thallus in Cladonia-like lichens having a prostrate primary thallus and upright secondary thallus.
Squamules are small flakes or scales of a lichen, often rounded, ear-like, or lobed, these units typically clustered into a colony.
Thallus attached by a single holdfast; can be foliose or fruticose.
Network of interconnected branches
Ramalina menziesii - Habit
Upper SurfaceFor fruticose lichens, these characteristics apply to all surfaces
Upper Surface Color (Dry)Check dry specimen away from lobe tips. Although colors are a critical characteristic in lichen identification, they are also highly variable between specimens, lighting, screens and eyeballs.
The Lichen Color Chart attempts to show the variation of colors and within a color.
Lichens with usnic acid in low concentrations may appear pale gray green.
This subtle but critical color in lichens indicates the presence of usnic acid, a secondary chemical which is very helpful in identification. In shade, it may look like green with a hint of dirty pale yellow. In sun, it may look more like a dirty pale yellow with hint of green (like chamomile tea).
Upper surface (dry) fluourescent yellow greenish (example: Letharia)
Upper surface (dry) light orange to dark orange or reddish orange
Upper surface (dry) pale sulphur yellow, banana, or deep egg yolk yellow
Upper surface (dry) whitish, including snow white and cream
Upper surface (dry) pale gray, ashy, neutral (without a greenish, olive, or brown tint)
Upper surface (dry) dark gray, battleship gray, neutral gray
Upper surface (dry) blackish, too dark to easily discern color
Upper surface (dry) blackish with an olive tint
Upper surface (dry) brown with an olive tint
Upper surface (dry) pale to deep olive green
Upper surface (dry) brown, including reddish brown, grayish brown, milk chocolate, dark chocolate, chestnut, sepia
Upper surface (dry) tan
Range of lobe widths in millimeters. Lognormal probability distribution used to calculate probabilities.
Upper surface with minute hairs that can be matted, felty, or erect
Upper surface pruinose or scabrous, the latter often crystalline in appearance. Pruina are superficial chemical deposits, usually whitish and usually formed from calcium oxalates, giving a frost-covered or floury appearance. Scabrous means a surface having a roughened appearance. With a hand lens or dissecting scope the texturing material often appears crystalline or glassy (i.e. partly transparent, unlike pruina which appear white and frosty).
Upper surface (or all surfaces for fruticose species) with a regular to irregular network of ridges
Upper surface with pseudocyphellae, which may be pale, dark, white and often inconspicuous. Pseudocyphellae is a broad term referring to any differentiated breaks in the cortex of lichens but that lack specialized cells surrounding the opening: these may be round, irregular, angular, or a minuscule pore.
Upper surface with holes into the hollow lobe interiors.
Menegazzia terebrata - Habit
Cilia are hair-like projections, usually applied to threadlike multicellular marginal hairs.Cilia present on the margins (foliose species) or projecting from branches as short, sharp, branches or spines (fruticose species).
The medulla is the interior layer of most lichens, composed mainly of fungal hyphae and generally white. If the entire medulla is pale yellow, deep yellow or orange, this characteristic is true.
Inside of fruticose thallus has a central cord. Characteristic of genus Usnea.
Lobes or stalks hollow
Lower SurfaceThese characteristics generally apply to foliose lichens or foliose lichens with squamules which have a lower surface.
Lower Surface Color (Dry)Check dry specimen away from lobe tips. Although colors are a critical characteristic in lichen identification, they are also highly variable between specimens, lighting, screens and eyeballs. The Lichen Color Chart attempts to show the variation of colors and within a color.
Lower surface (dry) pale gray greenish, including those with usnic acid in low concentrations.
This subtle but critical color in lichens indicates the presence of usnic acid, a secondary chemical which is very helpful in identification.
Lower surface (dry) pale greenish.
Lower surface (dry) dark green or dark greenish.
Lower surface (dry) light orange to dark orange or reddish orange.
Lower surface (dry) pale sulphur yellow, banana, or deep egg yolk yellow.
Lower surface (dry) whitish, including snow white and cream.
Lower surface (dry) pale gray, ashy, neutral (without a greenish, olive, or brown tint).
Lower surface (dry) dark gray, battleship gray, neutral gray.
Lower surface (dry) blackish, too dark to easily discern color.
Lower surface (dry) blackish with an olive tint.
Lower surface (dry) brown with an olive tint.
Lower surface (dry) pale to deep olive green.
Lower surface (dry) brown, including reddish brown, grayish brown, milk chocolate, dark chocolate, chestnut, sepia.
Lower surface (dry) tan.
Veins (raised branching or netlike strands) on the lower surface of foliose lichens.
Lower surface with rhizines which are multicellular root-like structures
Squarrose branching means branching by many short perpendicular branches from a single main axis.
Faintly to distinctly felty or the surface with short, fine fuzz; having a tomentum. Lower surface tomentose, pubescent, or with minute erect hairs (as opposed to bare or with multicellular rhizines)
Crater-like pores, usually in the lower surface of lichens, that open into the medulla and are lined with differentiated cells; characteristic of the genus Sticta.
Lower surface with pseudocyphellae. Pseudocyphellae are a broad term referring to any differentiated breaks in the cortex of lichens but that lack specialized cells surrounding the opening: these may be round, irregular, angular, or a minuscule pore.
PhotobiontCharacteristics related to the photobiont, the photosynthetic partner in the lichen.
This characteristic is true if the primary photobiont (photosynthetic partner in lichen) is a green alga. Green alga are usually found in a distinct bright green layer of the lichen.
This characteristic is true if the primary photobiont(photosynthetic partner in lichen) is a cyanobacterium. Cyanobacteria are prokaryotic photosynthetic organisms formerly known as "blue-green algae", generally having a blue-green tint and lacking chloroplasts. Cyanobacteria may be found in an an indistinct layer of the lichen or in special structures called cephalodia (ee next characteristic).
Cyanobacteria-containing structures in lichens which otherwise contain green algae; these structures usually appear as irregular warts or inclusions, or occasionally as squamules or minutely fruticose structures. Internal cephalodia present.
CladoniaCharacteristics specific to genus Cladonia.
Upright stalks (podetia) forming distinct cups
Upright stalks are richly branched (branched more than 5 times over the length of a mature individual)
Stalks becoming melanotic (darkened) at the base, with pale spots against a dark gray, brown, or black melanized background.
Cladonia phyllophora - Melanotic base
Stalks with branch axils or cups opening into the hollow interior by either small or gaping holes
Cladonia furcata - Apothecia
UsneaCharacteristics specific to genus Usnea. All Usnea species have a central cord or axis which is elastic. Usnea individuals can be quite variable with overlapping characteristics. Consult Macrolichens of the Pacific Northwest for more defining characteristics.
Cortical papillae (minute, discrete, usually rounded bumps) present
Branches cigar shaped, pinched at the nodes and slightly swollen in the internodes, with the medulla of the inflated parts relatively loose
Central axis pale yellow
Usnea flavocardia - Branches
Cortex of healthy thalli with distinct red or orange pigments (ignore reddish dead or dying parts)
Central axis thick, >2/3 thickness of branch
Usnea longissima - Branches
Main branches are nearly unbranched except for perpendicular fibrils
Usnea longissima - Field appearance
Surface wrinkled (foveolate, pitted, ridged, very subtle or distinct). Foveolate means with delicately pits or shallow surface depressions
Usnea cavernosa - Branches
Fibrils abundant (short perpendicular side branches) A fibril is a small fiber projecting from the thallus, roundish in cross section, usually produced at roughly right angles to the direction of growth, usually applied in Usnea.
Perithecia are a type of globose or flask-shaped ascocarp where the hymenium is completely enclosed by protective sterile tissue, except for a small opening at the tip, the ostiole. Perithecia are usually partially embedded in the thallus and appear as a small dot on the surface.
Apothecium are a sexual reproductive structure of the fungus; usually a disk- or cup- shaped structure lined with, at maturity, an exposed spore producing surface.
Alectoria sarmentosa - Apothecia
Candelaria pacifica - Apothecia
Cetraria orbata - Apothecia
Cladonia carneola - Apothecia
Cladonia umbricola - Apothecia
Fuscopannaria pacifica - Apothecia
Hypogymnia apinnata - Apothecia
Lobaria pulmonaria - Apothecia
Melanelia stygia - Apothecia
Melanohalea multispora - Apothecia
Nephroma helveticum - Lower
Peltigera neopolydactyla - Apothecia
Physconia americana - Habit
Pilophorus acicularis - Apothecia
Platismatia lacunosa - Apothecia
Scytinium gelatinosum - Apothecia, moist
Umbilicaria angulata - Apothecia
Mazedium are a type of apothecia where a modification of the hymenium of ascomycetes whereby the asci quickly disintegrate, producing a loose powdery spore mass that is added to from below and sloughed off at the top.