Field Key to Common Broad-Lobed Gray Foliose Lichens
1a Thallus with pores on the upper surface (pseudocyphellae, best seen with hand lens); undersurface pale (genus Punctelia)………….. 2
1b Thallus without pores, but may be uniform or variously cracked, ridged, or white-maculate; undersurface black or nearly so (except in some instances near lobe margins)…………….. 4
2a Thallus isidiate…………………. Punctelia rudecta
![](https://ohiomosslichen.org/wp-content/uploads/2021/08/species-Punctelia-rudecta-1-1000x750.jpg)
Punctelia rudecta
2b Thallus sorediate………………………………………. 3
3a Lobules abundant in center of thallus Punctelia missouriensis
![](https://ohiomosslichen.org/wp-content/uploads/2021/08/species-Punctelia-missouriensis-1-1000x750.jpg)
Punctelia missouriensis
3b Lobules absent…………………. Punctelia caseana
![](https://ohiomosslichen.org/wp-content/uploads/2021/08/species-Punctelia-caseana-1-1000x750.jpg)
Punctelia caseana
4a Upper surface strongly ridged with soredia erupting along the ridges. Crespoa crozalsiana
![](https://ohiomosslichen.org/wp-content/uploads/2021/08/species-Crespoa-crozalziana-1-1000x750.jpg)
Crespoa crozalziana
4b Upper surface not, or only faintly, ridged……. 5
5a Medulla pale yellow (sometimes only under soralia, white elsewhere); a medium-sized species with thallus closely appressed to substrate…………………… Myelochroa aurulenta
![](https://ohiomosslichen.org/wp-content/uploads/2021/08/species-Myelochroa-aurulenta-1-1000x750.jpg)
Myelochroa-aurulenta
5b Medulla white throughout; especially large lichens extended with ascending lobes (genus Parmotrema)…………………………………………… 6
6a Thallus without lichenized asexual propagules; apothecia abundant…. Parmotrema perforatum
![](https://ohiomosslichen.org/wp-content/uploads/2021/08/species-Parmotrema-perforatum-1-1000x750.jpg)
Parmotrema perforatum
6b Thallus sorediate………………………………………. 7
7a Lower surface black with marginal zone ca. 1 cm wide; lobe margins with prominent eyelashlike cilia and linear soralia; overall form very “ruffled”.. Parmotrema hypotropum
![](https://ohiomosslichen.org/wp-content/uploads/2021/08/species-Parmotrema-hypotropum-1-1000x750.jpg)
Parmotrema hypotropum
7b Lower surface brown in marginal zone; margins eciliate; thallus lobes only moderately elevated (not especially ruffled)… Parmotrema reticulatum
![](https://ohiomosslichen.org/wp-content/uploads/2021/08/species-Parmotrema-reticulatum-1-1000x750.jpg)
Parmotrema reticulatum