1a Thallus with veins on the lower surface (occasionally the veins ± obscure); lower cortex absent (appearing dull and fibrous under lens)
2a Medulla white; lower surface never orange
2b Medulla orange; lower surface orange with brown veins with brown veins
1b Thallus without veins on the lower surface; lower cortex present or not
3a Thallus minutely foliose or subfoliose; lobes < 2 mm wide
4a On bark or wood
5a Cortex or medulla P+O; thallus with definite lobes
5b Cortex and medulla P-; thallus with definite lobes or nearly squamulose
(Parmeliella is also keyed under Fuscopannaria. Koerberia biformis, a minute blackish-olive species on trees in Cal, would also key here.)
4b On rock, mosses, or humus over rock
6a On mosses or humus over rock or bark, sometimes directly on rock; thallus brown or bluish brown; lobes never longitudinally ridged
7a Thallus brown or dark brown; lobes isidiate to lobulate; spores 2-4 celled
7b Thallus gray or brownish gray; lobes isidiate becoming sorediose; spores simple
6b On rock; thallus blackish, gray green, or olive colored; lobes often longitudinally ridged or striate
8a Lower surface dark
8b Lower surface pale
9a Isidia and lobules lacking; apothecia usually present. Arctic s to s WA, rare in PNW
9b Isidia and/or lobules present; apothecia occasionally present
10a Isidia very slender, cylindrical to + flattened; lobes very thin, elongate, fan-tipped, and tightly appressed; apothecia margins thalline; rare w Cas, more common northward
10b Isidia present or not, but with abundant narrow lobules, the lobules mostly flattened (some cylindrical) and arising from fine divisions of the lobe margins, often becoming densely shingled on the upper surface; lobes thicker, shorter, and less tightly appressed than the preceding species, generally fan-tipped in part; apothecia margins variable, thalline or with a false proper margin
3b Thallus medium to large foliose; lobes > 2 mm wide
11a Lower surface with discrete white or yellow spots or pores (cyphellae or pseudocyphellae) < 2 mm diameter
12a Lower surface with broad (generally 0.5-2 mm) whitish craters (cyphellae)
12b Lower surface with small (generally < 0.5 mm) white or yellow spots (pseudocyphellae or papillae)
13a Spots on lower surface white or yellow, concave to slightly convex (pseudocyphellae); apothecia, if present, on the upper surface; upper surface dark brown, brown, gray, or greenish gray
13b Spots on lower surface white, raised (papillae); apothecia on the lower surface of the lobe tips; upper surface brown togray brown
11b Lower surface lacking discrete white or yellow spots or pores, but in some spp with whitish patches > 2 mm diameter
14a Lobes large, usually > 1 cm broad; lower surface with fine tomentum interrupted by naked, white patches; upper surface weakly undulating or with a network of prominent ridges
14b Lobes smaller, usually < 1 cm broad; lower surface without naked, white patches or without tomentum; upper surface weakly or not at all ridged
15a Apothecia on lower surface of lobe tips; thallus brown to gray brown; soredia present or not
15b Apothecia absent or not on lower surface; thallus gray, brownish gray, olive, greenish gray or yellowish; soredia or lobules present; rare spp
16a Lobules or apothecia present
17a Lobules present, containing green algae, thallus otherwise with a blue-green photobiont; soredia absent
17b Lobules present or not; apothecia present, the whole thallus containing cyanobacteria
18a Lower surface with a felty mat of blue-black rhizines and tomentum; thallus P-. Arctic-alpine, Alas and OP; rare
18b Lower surface with whitish or bluish rhizohyphae; thallus P+O (eriodermin)
16b Lobules absent; soredia present and containing blue-green photobiont
19a Soredia laminal; lower surface bare; upper surface yellowish tinged when dry, bluish gray when moist
19b Soredia marginal; lower surface tomentose; upper surface grayish, not tinged with yellow
20a Upper surface with stiff erect hairs (use lens); thallus P+O
20b Upper surface with matted cobwebby hairs, never with stiff erect hairs; thallus P-