A conspicuous species with fruticose rigid thalli, isotomic-dichotomous branching and terminal apothecia. Its main secondary metabolite in the medulla is thamnolic (K+ yellow, UV-) or squamatic acid (K-, UV+ bluish). It might be confused with U. intermedia, which is also fertile but distinguished by a more or less pendent thallus and the presence of salazinic acid.
In Europe, U. florida used to be widely distributed from the temperate to hemiboreal zone, however, it receded during the 20th century and is currently rare. It prefers higher air humidity, both in the mountains and in the lowlands. The species mainly grows in treetops (mainly on oak, rowan, sycamore and beech in the Czech Republic), so it is often overlooked. It is currently rare in the Czech Republic, with scattered localities mainly in south and south-west Bohemia (e. g., the Šumava Mts). Its historical distribution requires a revision of the herbarium material. Surprisingly, it is indistinguishable from the sterile sorediate-isidiate U. subfloridana based on various molecular methods (see, e. g., Degtjarenko et al. 2020). They probably represent two young, recently split sister species and whole-genome studies may be needed for their distinction on the molecular level.
Literature: Degtjarenko P., Mark K., Moisejevs R., Himelbrant D., Stepanchikova I., Tsurykau A., Randlane T. & Scheidegger C. (2020): Low genetic differentiation between apotheciate Usnea florida and sorediate Usnea subfloridana (Parmeliaceae, Ascomycota) based on microsatellite data. – Fungal Biology 124: 892–902.taxonomic classification:
All records: 19, confirmed 16. One click on a selected square displays particular record(s), including their source(s).