Proc. Amer. Acad. Arts Sc., 5: 397, 1862. Basionym: Dufourea ramulosa Hook. - Bot. Appendix Parry J. Sec. Voy.: 414, 1825.
Synonyms: Dufourea muricata Laurer
Distribution: N - TAA (Tretiach 1993), Lomb (Dalle Vedove & al. 2004), VA (Piervittori & Isocrono 1999).
Description: Thallus fruticose, lossely attached, straw-coloured, spotted brownish yellow or pale violet-pruinose, shrubby. Branches to 2.5 cm tall, 1-2(-3) mm thick, erect to prostrate, subterete, fragile, dying at base, more or less sympodial with a few branches, but many short, often black-tipped side branches, usually forming tufts. Cortex compact, up to 50 µm thick, prosoplechtenchymatous, the cells thick-walled, sharply distinguished from the arachnoid medullary hyphae; medulla hollow, with a few loosely arranged hyphae scattered in the cavity. Apothecia extremely rare (never found in Italian material), on the tips of lateral branches, 1-3 mm broad, with a brown disc. Asci 8-spored, Lecanora-type. Ascospores 1-celled, hyaline, biseriate in the asci, globose, 4.5-6 µm in diam., thick-walled. Pycnidia rare, dark, knobby, more frequent on laterasl branches. Conidia cylindrical ot fusiform, straight, 5-7 x c. 1 µm. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC- or KC+ yellow to pink, P-; medulla K-, C-, KC+ red, P+ red or P-. Chemistry: usnic acid (cortex) and usually physodalic and physodic acids in the medulla (in which case it reacts P+ red).
Note: an arctic-alpine, circumpolar species found on soil developing from calcareous schists above treeline; probably confined to the Alps in Italy.
Growth form: Fruticose
Substrata: soil, terricolous mosses, and plant debris
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by thallus fragmentation