Usnea glabrescens var. fulvoreagens Räsänen

van den Boom, Pieter P. G., Clerc, Philippe & Ertz, Damien, 2015, New records of lichens and lichenicolous fungi from La Gomera (Canary Islands, Spain), including the new species: Usnea boomiana P. Clerc, Candollea 70 (2), pp. 165-177 : 172

Usnea glabrescens var. fulvoreagens Räsänen

(≡ U. fulvoreagens (Räsänen) Räsänen )

Notes. – This taxon is a new record for the Canary Islands. CLERC (2011) considered it as a synonym of U. glabrescens because there are many intermediate forms, especially in North America. However, in Europe, most of the specimens can be reliably identified to one or the other varieties, justifying their acceptance. Usnea glabrescens var. glabrescens has well delimited circular soralia that are not at all or little excavate whereas U. glabrescens var. fulvoreagens has distinctly excavate U. lapponica like soralia. See CLERC (2007) for a detailed description of this taxon.

Material examined. – 12, Er, Boom 46119; 24, Er, Boom 46386/a; 55, Pn, P. Clerc G262086 .