lichens of the lower ozark region of missouri and arkansas

Key C: Squamulose lichens (continued)
12. Squamules ca. 1 mm wide, brownish gray with dark thickened margins; on
siliceous rocks or silty soil pockets over siliceous rocks .... Psorula rufonigra
12. Squamules mostly > 1 mm wide, brown to reddish brown, margins, if thickened,
pale; on calciferous rocks or soil ...................................13
13. Terricolous ...........................................Psora
13. Saxicolous ...............................................14
KEY D: STERILE CRUSTOSE LICHENS
14. Squamules pale beneath, with ± thickened, whitish margins; apothecia
reddish brown; hymenium IKI- ............................Psora
14. Squamules dark beneath, with thin, brown to dark margins; apothecia
black; hymenium IKI+ blue ........................Lecidea lurida
1. Thallus leprose, of undifferentiated powdery masses of fungal hyphae loosely enveloping algal
cells, lacking any vestige of cortex or morphological organization (occasionally appearing indistinctly
lobed along margin) ............................................................2
2. Thallus yellow or with distinct yellow tints (if greenish yellow, see # 2 below) .........3
3. Thallus bright lemon yellow ..................................... Chrysothrix
3. Thallus dull grayish or brownish yellow .....................................4
4. Thallus K+ deep grape purple (unknown substance with R f of 1/2/1); on siliceous rocks
.................................................... Leproloma vouauxii
4. Thallus K+ reddish magenta (parietin); on dry sheltered carbonate faces ..........
................................................Caloplaca chrysodeta
2. Thallus greenish to bluish or gray .............................................5
5. Usnic acid present ............................................... Lecanora
5. Usnic acid absent ................................................ Lepraria
1. Thallus not totally leprose, at least partially corticate and/or morphologically organized and
differentiated .................................................................6
6. Thallus yellow to orange ....................................................7
7. Upper cortex K+ deep magenta (parietin) ............................ Caloplaca
7. Upper cortex K- or K+ weakly reddish (calycin) ..............................8