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

Life habit: lichenized Thallus: crustose, continuous, cracked, thin, usually poorly developed, endo- to episubstratal; or seldomly areolate, rarely leprose; prothallus: sometimes forming an irregular black or dark brown border surface: white, pale gray or pale green, smooth, effuse, lacking isidia or soredia anatomy: in section appearing +paraplectenchymatous, ecorticate and without a differentiated medulla photobiont: primary one a trentepohlioid alga, secondary one absent Ascomata: apothecioid, sessile, with constricted base, +round, 0.2-2.5 mm in diam., scattered or rarely 2-4 together and then slightly contorted through mutual pressure, central column of sterile tissue occasionally present disc: black, at first usually concave but soon plane to slightly convex, covered by +dense pale green, orange or red pruinose but often only present in younger apothecia margin: lecideine, glossy black, prominent, raised above disc, smooth or more often denticulate or crenulate, persistent, epruinose exciple: well developed, dark brown to carbonaceous, K+ dark green or olive brown, composed of conglutinate, thick-walled hyphae, closed at bottom and extending down towards into the medulla or substrate; hyphal walls: strongly gelatinized; usually with individual hyphae not easily discerned but sometimes distinguishable in outer part and then anti-clinally arranged hymenium: hyaline, I+ blue/red or pale red, K/I+ blue, with hymenial strand of excipular tissue intruding between the paraphysoids (ascostromata multiascal, pluricarpocentral, sensu Tehler [1990]); paraphysoids: hyaline, septate, simple or sparsely branched, with few or no anastomoses, up to 2.5 µm wide; apical cells: clavate, with distinct pale or dark brown cap which is formed in the outer or seldom in the inner part of the cell wall, forming a granulose, dark brown pseudoepithecium, K+ yellow or rarely purple; under polarized light the granules pale yellow to pale red; subhymenium: pale brown or rarely hyaline asci: bitunicate with fissitunicate dehiscensce, clavate to cylindrical-clavate, slightly stiped, 8-spored; exoascus: thin and refringent; endoascus: varying thickness depending on development state, 2-layered, both layers hemiamyloid (K/I+ blue), but in the internal endoascus there is a thick, strongly amyloid band, with an easily distinguishable ring structure and a small ocular chamber, without apical nasse (abietina-type) ascospores: hyaline, rarely brownish when old, 3-19-septate transversely, oblong-fusiform, fusiform to acicular-fusiform, straight or somewhat curved, thick-walled and +widened at septa, 11-85 x 3-9 µm; surface: smooth, without distinguishable gelatinous sheath Conidiomata: pycnidial, solitary, punctiform, immersed or subimmersed in thallus, epruinose, globose to subglobose; walls: dark brown or carbonaceous above, hyaline to pale brown in inner part; conidiophores: type I or II of Vobis (1980), with conidiogenous cells in terminal position conidia: hyaline, with oblong, straight and short, 3-5 x 1-1.5 µm Secondary metabolites: orcinol depsides or secondary metabolites absent Geography: tropical to temperate Substrate: on bark or wood. Notes: Cresponea differs from Lecanactis (L. abietina group) in having epruinose apothecial margins, excipular hyphae without crystals (soluble in K), pale yellow to red pseudoepithecial granules (K+ yellow or purple), scarcely anastomosed paraphysoids, thick-walled spores with +widened septa, thick perispores, and differentiated endospores. See Egea and Torrente (1993) for fuller description of the genus.