Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.

Thallus: crustose, composed of scattered to crowded areoles forming small patches 1.5-3.5 mm across areoles: flat to somewhat convex, rounded, angular or irregular in outline, up to c. 0.25 mm wide surface: greenish yellow to yellow Apothecia: common, lecanorine, 0.15-0.4 mm wide disc: darker yellow than the thallus, ±plane to somewhat convex margin: uneven, entire to granular to ±excluded exciple: sometimes visible from the outside, thin to thick epihymenium: yellow-brown hymenium: hyaline, 60-75 µm tall; paraphyses: simple or sometimes branched apically, cylindrical or with somewhat swollen, to 3.5 µm wide tips; hypothecium: hyaline asci: clavate, 24-32+-spored ascospores: hyaline, simple to 1-septate, oblong to ovoid, 7-12 x 4-5 µm Pycnidia: not seen Spot tests: K- to K+ reddish, KC-, C- Secondary metabolites: not investigated, probably the same pulvinic acid derivatives as in the other species of the genus. Substrate and ecology: on bark of broad-leafed trees, shrubs and conifers, often on twigs and branches World distribution: circumpolar(?) in the Northern Hemisphere Sonoran distribution: rather common in open montane forests in central and northern Arizona up to at least 2900 m. Notes: Candelariella lutella is a fairly common, but it is minute and easily overlooked species. It is characterized by its small apothecia and its small areoles forming very small yellow patches typically at the base of small branchlets or next to cracks in the bark. Candelariella xanthostigma has a granular thallus, which often forms widespread stands and mostly has larger apothecia, and C. vitellina is normally a much larger species.

Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.

Thallus: crustose, composed of scattered to crowded granules, often ±evenly dispersed on the substrate, sometimes aggregated into thicker crusts granules: mostly round, 0.04-0.08 mm wide, sometimes becoming elongated surface: green yellow to yellow, smooth Apothecia: lacking to abundant, lecanorine, 0.3-0.7 mm wide margin: initially entire, later becoming granular and sometimes excluded exciple: often visible from the outside as a raised margin disc: darker yellow than the thallus, flat, becoming convex in old apothecia epihymenium: yellow-brown hymenium: hyaline, 55-70 µm tall; paraphyses: simple, ±cylindrical or somewhat swollen apically, tips to 3 µm wide; hypothecium: hyaline asci: clavate, 16-24-spored ascospores: hyaline, simple to 1-septate, ovoid to oblong, 7.5-11 x 3.5-4.5 µm Pycnidia: common, appear as darker yellow granules conidia: hyaline, ellipsoid to oblong, 2.5-3.5 x 1.5 µm Spot tests: K+ reddish, KC-, C- Secondary metabolites: calycin, pulvinic acid, pulvinic dilactone and vulpinic acid. Substrate and ecology: on the bark of broad-leaved trees and shrubs, sometimes on conifers and wood World distribution: world-wide Sonoran distribution: in coastal areas of southern California and Baja California including the Channel Islands and in open montane forests in Arizona up to the timberline. Notes: Candelariella xanthostigma is characterized by a thallus that is +entirely composed of small round granules. The likewise polysporous C. lutella has a thallus of small ±flat areoles and C. vitellina has a thallus convex areoles becoming minutely lobate.