This key includes all species I have studied and am fairly confident of the identification. There are several additonal undescribed species and some species I have not seen. This is subject to further revision. See my paper in Mycologia 99: 292-314. 1996 (1997).
Last revised 26 February, 1998. American species in bold.
1. Thallus brown, areolate; apothecial disks darker brown; spores
12.5-14 X 7.5-8.5 um, isthmus 6-7 µm; China
.....................................................................................................
C. cupreorufa
1. Thallus gray, white or immersed
...........................................................................................
2
2. Spores with 4 locules
...........................................................................................................
3
2. Spores with 2 locules
...........................................................................................................
4
3. On rock; not isidiate; Costa Rica
...................................................................... C.
tetramera
3. On bark; isidiate; Hawaii, Nepal
......................................................................... C. spadicea
4. On bark, wood or plants
.....................................................................................................
5
4. On rock
............................................................................................................................
18
5. Epihymenium blue or bluish purple
...................................................................................... 6
5. Epihymenium gray, brown or golden
................................................................................... 7
6. Epihymenium producing abundant purplish-blue solution in KOH;
epihymenium dark bluish purple; paraphyses abundantly branched at tips; apothecia brown to
dark brown with rusty
red tinge; spores 12.5-15.5 X 5.5-8.5 µm, isthmus 4.2-7 um; Calif., BC, Idaho
.............. C. atrosanguinea
6. Epihymenium K-; epihymenium blue; isthmus very narrow (1.5 um);
thallus gray; apothecial disks black, margin black; spores 11.2-12.6 X 5.5 µm, isthmus
1.5 µm (barely more than a septum); Minn, Mich.
..........................................................................................................
C. parvula
7. Apothecial disks tan, pale; spore isthmus 7-11 um; thallus
yellow-white; epihymenium K-; Spores 14-18 X 7-10 µm; Colombia
.................................................................. C. pallidior
7. Apothecial disks brown or darker; spore isthmus 3-5.5 um
................................................ 8
8. Epihymenium K+ violet or K+ brown turning violet
............................................................ 9
8. Epihymenium completely K- or K+ yellow
...................................................................... 14
9. Thallus with pseudocyphellae and/or isidia; radiating hyphae in
upper exciple; spores with thickened end walls; spores 14-15.5 X 7-8.5 µm, isthmus 4-5.5
µm; tropical ...... C. neotropica
9. Thallus without pseudocyphellae and isidia
...................................................................... 10
10. Epihymenium K+ strong red turning purple with colored solution; no
prothallus; apothecia 0.3-1.0 mm; paraphyses not swollen, frequently branched; spores with
thick end walls, 12.5-17 X 7-10 µm, isthmus 4-7 µm; common N. Amer
......................................................... C.
pollinii
10. Epihymenium K+ weak violet or K+ blue, no red color
................................................. 11
11. Epihymenium golden, K+ blue
...................................................................................... 12
11. Epihymenium gray, K+ weak violet
............................................................................... 13
12. Apothecial margin same color as disk; spores 14-15.5 X 7-8.5 µm,
isthmus 4-5.5 µm; Brasil
............................................................................................................................
C. diducenda
12. Apothecial margin same color as thallus; spores 12.5-17 X 7-8.4 µm,
isthmus 3 um
.............................................................................................................................
C. sp. Hawaii
13. Spores 11-12.5 X 5.5-7 µm, isthmus 3-4 µm; no prothallus; Sweden
............ C. suspiciosa
13. Spores 11-14 X 5.5-7 µm, isthmus 5.5-7 µm; black prothallus
present; apothecia small (0.2-0.4mm); tropical, Caribbean, Paraguay
........................................................ C.
floridana
14. Epihymenium K+ yellow; apothecia similar to Lecanora subfusca;
small oval cells in upper exciple; spores 14-18 X 7-10 µm, isthmus 4-7 µm; Texas, Mexico
[NOTE: This species has recently been found in additional localities in Mexico and often
has a dull orange disk with K+ red epihymenium (anthraquinones)]
............................................................................. C. diphasia
14. Epihymenium completely K-
.........................................................................................
15
15. Upper exciple with radiating hyphae
.............................................................................. 16
15. Upper exciple with large oval cells
................................................................................ 17
16. Disks pruinose, apothecia 0.3-1.5 mm; paraph. tips hardly swollen;
spores 11-14 X 5.5-7 µm, isthmus 4-5.5 µm; Common SE and E N. Am.
................................................. C.
camptidia
16. Disks epruinose, dark brown, apothecia 0.2-0.6mm; spores 10-12.5 X
4-5.5 µm, isthmus 4-5.5 µm; Central N. Am.
............................................................................. C. brunneola
17. Soredia absent; thallus subsquamulose; spores 10-12.5 x 5.5-7 µm,
isthmus 4-5.5 µm; North & South Dakota, Arizona, Texas
......................................................................... .C. dakotensis
17. Soredia present; thallus of dispersed low areoles; paraph. tips
swollen; spores 10-14 X 5.5-7 µm, isthmus 4-7 µm; Rare
.............................................................................. C. obscurella
18. Epihymenium K+ dark bluish-purple; epihymenium dark brownish
violet; no algae in upper margin; spores 11-14 X 7-8.5 µm, isthmus 3-4 µm; Sweden
....................... C. atrocyanescens
18. Epihymenium K- or weakly K+ violet
......................................................................... 19
19. Thallus immersed or almost absent, not abundant
......................................................... 20
19. Thallus on surface, obvious, more abundant
................................................................. 21
20. Spore septa often poorly developed or with wide canal; epihymenium
purplish brown; no algae in upper margin; thallus scant, white; rock HCL+; apothecial
margin usually black; disks black, non-pruinose; spores 15.5-21 X 5.5-10 µm, isthmus
0-1.5 µm; western N. Am. ................ C. oblongula
20. Spore septa well developed, canal narrow; epihymenium hyaline to
light brown; apothecia immersed in rock; spores 10-15.5 X 7-8.5 µm, isthmus 3-4 µm;
Europe .................. C. alociza
21. Apothecia immersed in thallus at maturity; epihymenium K+ violet;
spores 10-12.5 X 5.5-7 µm, isthmus 3-7 µm; Europe
.................................................................................... C.
chalybaea
21. Apothecia sessile at maturity
.........................................................................................
22
22. Apothecial margin with dense granules (disolving in KOH); thallus
usually K+ yellow (atranorine); epihymenium usually K-, sometimes slightly K+ muddy violet
........................... 23
22. Apothecial margins without soluble granules; thallus K-
................................................. 26
23. Apothecial disks pale tan; apothecial margin thick, raised; spores
12.5-14 X 5.5-7 µm, isthmus 4 µm; Hawaii
.......................................................................................................
C. albidella
23. Apothecial disks brown to dark brown
........................................................................ 24
24. Apothecial margin thick, raised, black; thallus thin, smooth;
spores 12.5-14 X 7-8 µm, isthmus 7 µm; Andeman Isl.
.................................................................................................
C. kurzii
24. Apothecial margins moderate to thin, flush, same color as thallus or
dark brown ............ 25
25. Spores 14-15.5 X 7-8.5 µm, isthmus 4-5.5 µm; apothecia with only
thalloid margin (light color); Rodriguez
....................................................................................................
C. carneofusca
25. Spores 10-12.5 X 5.5-7 µm, isthmus 4-7 µm; apothecia usually with
dark inner and pale outer thalloid margin; Caribbean
.................................................................................. C. diplacia
26. Spores small and narrow (10-12.5 X 4-5.5 µm); young apothecia
often sunken in thallus .. 27
26. Spores larger (over 10 um long, over 7 µm wide) all apothecia raised
from thallus ............ 28
27. Thallus and apothecial margin K+ violet, 10% N+ violet
(thalloidima green); thallus dark gray; epihymenium light brown; thallus K- (macro);
areoles moderate; disks flat, dark brown to black; epihymenium weakly K+ violet; spores
10-12.5 X 4-5.5 µm, isthmus 3-4 µm; common .......... C.
conversa
27. Thallus and apothecial margin K-, cN-; apothecial margin 10% N+ pale
violet (lecidea green); thallus whitish gray; spores 10-14 X 4-5.5 µm, isthmus 3-4 µm
............................. C. sp China
28. Thallus all subsquamulose, partly stipitate areolate, thick;
thalloid margin of apothecia usually thick and dominant;
.......................................................................................................
29
28. Thallus areolate, not stipitate or only partly so, sometimes thin
................................... 30
29. Thallus shiny olive brown, disks brown; epihymenium K+ violet;
spores 14-17 X 7-8.5 µm, isthmus 3-4 µm; Calif.
..................................................................................... C. peliophylla
29. Thallus bluish-gray, usually mottled, areoles stipitate in places;
cortex thick and uneven; algal in clumps and columns; disks black to dark brown;
epihymenium weakly K+ violet; spores 14-18 X 7-10 µm, isthmus 1.5-3.5 µm; Rocky Mts.
................................................ C.
albovariegata
30. No algae in upper amphithecium, internally brown; spores 14-16 X
7-8.5 µm, isthmus 4-5.5 µm; Antarctic
......................................................................................... C.
austroshetlandica
30. Alage in upper amphithecium, internally not brown
......................................................... 31
31. Apothecial disks pale tan; no granules in margin; spores 12.5-14 X
7-8.5 µm, isthmus 4 µm; S Pacific
................................................................................................................
C. pallescens
31. Apothecial disks brown to dark brown
.......................................................................... 32
32. Apothecia or margins white pruinose; prothallus black when
present; epihymenium weakly K+ violet; spores 12.5-15.5 X 7-8.5 µm, isthmus 3-3.5 µm;
mainly Europe, rare N. Am. (N. Mex.)
...........................................................................................................................
C. variabilis
32. Apothecial margins and disks never pruinose
............................................................... 33
33. Spore isthmus 1.5-3 µm; thallus smooth, cracked areolate, algal
layer even, little or no necral layer on upper surface; spore isthmus very thin or
sometimes absent; epihymenium weakly K+ violet; spores 14-15.5 X 7-8.5 µm, isthmus 1.5-3
µm; Common ........................... C. atroalba
33. Spore isthmus 3-5.5 µm
..............................................................................................
34
34. Epihymenium and thallus K+ violet; spores 14-17 X 7-8.5 µm;
Europe ......... C. diphyodes
34. Epihymenium and thallus K-; spores 12.5-14 X 7-8.5 µm, isthmus 3
µm; Bear Isl. ..... C. ursina