Common Lichens of Wisconsin 1 his booklet portrays the 30 most common lichen Anatomy and Reproduction species of the approximately 800 species in The body of a lichen is called a thallus, and is covered Wisconsin based on the frequency the lichens T by a cortex, followed by a layer of algae, then a layer have been collected. They are grouped alphabetically of fungal filaments called a medulla, with a lower by Latin name within lichen type. Many of these surface sometimes covered in root-like attachment 30 species can be identified in the field, but most structures called rhizines. The latter do not function others can only be identified in the laboratory using as roots, and only attach the lichen to the substrate. microscopic and chemical characters. Users of this booklet are encouraged to either use the references upper cortex listed at the end or contact the authors for more algae information or help. medulla What is a lichen? lower cortex A lichen is a symbiotic compound organism rhizines composed of an alga growing inside a fungus. They contain no vascular tissue so they tend to be small. Lichens reproduce sexually by producing spores from They are dormant when dry, but rapidly change color a fruiting body called an apothecium, or asexually and grow when wet. They reproduce both sexually by soredia (soralia) or isidia that contain clusters and asexually. of the fungal and algal cells, or by fragmentation of the thallus (lobules). Some lichens have a frosted Three types of lichens appearance due to the presence of pruina, which are calcium oxalate crystals grouped in such a way they Crustose: reflect light. Other lichens have holes in the cortex thin, paint-like tissue called pseudocyphellae. tightly attached to the substrate. Crustose species in this booklet are 10-30 mm across. Foliose: large, leaf-like tissues free apothecia soredia isidia of the substrate. Patches of these range from 10 – 30 cm Habitats across depending on age Lichens can grow in almost any habitat, but are most and species. common in forests, bogs, sand barrens, cliff faces and talus, rock outcrops, and cemeteries. Look for lichens on trees and shrubs, dead tree trunks and Fruticose: fences, most kinds of rocks including tombstones, three-dimensional complex soil, weathered metal and plastic surfaces, and roof (one or two parts) tissues. shingles. Lichens are sensitive to air pollution and Individual thalli are 1-4 cm consequently are not common in cities. They are also in size, but colonies can abundant in agricultural areas due to the fertilization range up to half a meter to a effects of atmospheric ammonia. The greatest lichen meter in area. diversity in Wisconsin is in the northern part of the state, especially in bogs and boreal forests. 1 2 Frosted comma lichen Chrysothrix caesia Brown-eyed rim lichen Lecanora allophana Very common on tree branches with colorful bluish The reddish-brown apothecia of this species stand purple apothecia due to calcium oxalate crystals. out from the white to grey thallus crust, typically Prefers smooth bark. Formerly in the Arthonia genus. found on smooth bark of many hardwood tree Occurs statewide and is common in cities. species. It can be found statewide. CRUSTOSE CRUSTOSE Common script lichen Graphis scripta Fused rim lichen Lecanora symmicta One of a group of lichens whose apothecia are slit- This Lecanora has yellow to orange, hemispherical shaped instead of disk-shaped. The black apothecia apothecia that swell up above the crustose thallus, grow in groups against a white thallus giving it the which is almost non-existent. It occurs throughout appearance of writing from a distance. It is most the state on bark and old wood of both conifers and common on smooth bark but occasionally occurs on hardwoods. rough bark. Occurs statewide. 3 4 Candleflame lichen Candelaria concolor Speckled greenshield Flavopunctelia flaventior The bright yellow color makes this lichen very This lichen differs from the common greenshield by conspicuous on tree trunks and branches statewide. the presence of tiny, white holes in the upper surface. It is pollution tolerant and occurs in cities. The tiny It also grows on tree trunks and branches statewide. lobes can be seen with a hand lens. FOLIOSE FOLIOSE Common greenshield Flavoparmelia caperata Hooded tube lichen Hypogymnia physodes One of the larger foliose species in the state, this One of a group of species characterized by having yellow-green lichen can grow on tree trunks to 20-30 hollow lobes, hence the general morphology of cm if the tree is old. Smaller individuals occur on a tube. This species occurs on both conifer and branches. It rarely has apothecia, and can be covered hardwood tree branches and trunks abundantly in in soredia in the older parts. This is the most common northern WI, and has also been used in air pollution species in the state. monitoring. 5 6 Powdery axil-bristle lichen Myelochroa aurulenta Hammered shield lichen Parmelia sulcata A foliose species with hairs along the margins and Similar to Parmelia squarrosa except this species a distinctive yellow color in the tissue below the has soredia (reproductive structures with no cortex) soredia, making it easy to identify. It grows mostly on instead of isidia. This species occurs statewide. oak and maple trees throughout the state. FOLIOSE FOLIOSE apothecia Bottlebrush shield lichen Parmelia squarrosa Dog lichen Peltigera canina The narrow gray lobes, bottlebrush rhizines (root- This soil lichen turns dark green/black when wet due like structures on the lower surface), and presence to the presence of cyanobacteria, the only lichen of of isidia (reproductive structures with a cortex) this type in this booklet. The red-brown apothecia make this lichen that grows on deciduous tree bark are oriented vertically on erect lobes. Species in this distinctive. It mostly occurs in the northern half of the genus are called dog lichens due to the resemblance state with some exceptions in the southern part. of the apothecia to dog ears. Occurs statewide. 7 8 Orange-cored shadow lichen Mealy rosette lichen Physcia millegrana Phaeophyscia rubropulchra This species is small, grey-green, and covered with A small, green/brown lichen with narrow lobes and a granular soredia that give it a powdery appearance unique orange/red medulla (internal tissue), that can like no other species on tree branches and trunks be seen when the thallus is broken. It occurs on tree throughout the state. The soredia are found on the trunks and branches statewide. margins that coalesce to form mounds of granules, FOLIOSE masking the white spotted thallus in the center. FOLIOSE Hoary rosette lichen Physcia aipolia Star rosette lichen Physcia stellaris A tree branch rosette-forming lichen with very Very similar to Physcia aipolia except the apothecia abundant apothecia that appear white to blue due are usually not pruinose, and the disks appear red- to thick pruina (calcium oxalate crystals). It prefers brown. It also has a different chemistry. It occurs nitrogen-rich environments like cities and agricultural statewide. areas with high light. Blow-down branches in cities are usually covered in this lichen. It is common throughout the state. 9 10 Bottlebrush frost lichen Physconia detersa Rough speckled shield lichen Punctelia rudecta A brown lobed species distinguished by the Similar to Punctelia bolliana except for the appearance of pruina at the margins and especially at abundance of isidia in the older parts of the thallus. It the lobe tips, giving a frosted appearance. It grows on is abundant statewide. tree trunks in hardwood forests throughout the state. FOLIOSE FOLIOSE Eastern speckled shield lichen Punctelia bolliana Powdery sunburst lichen Similar to Parmelia but distinguished by the presence Xanthomendoza ulophyllodes of small holes in the upper surface (pseudocyphellae A brilliant yellow to orange lichen with soredia – use hand lens). This species is greenish-grey along the margins and abundant white rhizines. It with a tan lower surface, and occurs on the bark of is very common on hardwood trunks and branches hardwoods statewide. throughout the state. 11 12 Ladder lichen Cladonia cervicornis ssp. verticillata Common powderhorn Cladonia coniocraea The cups (apothecia) proliferating from the centers of Unlike Cladonia chlorophaea this species has no cups lower cups makes this lichen very distinctive and easy at all, and appears awl-like. The surface has little to identify. It occurs on mineral soils and occasionally cortex, so the algal component shows through the on soil over rocks and occurs statewide. fungal component giving it a mottled green/white FRUTICOSE appearance. Often grows among other Cladonias in the same habitats as Cladonia chlorophaea. FRUTICOSE Mealy pixie-cup Cladonia chlorophaea British soldiers Cladonia cristatella The most common pixie cup lichen, covered with fine This is the only cupless, red-fruited Cladonia without dusty particles (soredia), occurs statewide on soil, soredia in the state, and is easy to identify. It is most rotting logs, and tree bases in well-lighted sites. common on sandy soils, rotting logs, tree stumps in the northern part of the state, and occasionally in the south. 13 14 Reindeer lichen Cladonia rangiferina Boreal oakmoss Evernia mesomorpha This highly branched, grey Cladonia has no cups, This shrubby, branched and tufted species is covered and the branch tips typically point in one direction. in soredia and occurs on the trunks and branches of It often grows in clumps and mats. It is common many tree species, mostly in northern WI. It has been on poor and/or boggy soils and along roadsides in widely used in air pollution monitoring due to its FRUTICOSE northern WI and occasionally in the south. abundance and ease of collection. FRUTICOSE Dragon cladonia Cladonia squamosa Sinewed ramalina Ramalina americana The stalks of this species are covered in leaf-like A tufted lichen with solid, flat branches and yellowish projections called squamules, topped by cups or not apothecia that grows on tree trunks and branches along with brown fruits.