ASCOMYCOTA | LECANOROMYCETES > LECANORALES > Parmeliaceae

Genus Usnea, meaning 'rope-like' - or from the Arabic for 'moss'

Common name:            Inflated Beard Lichen

Synonym:                    Usnea inflata  

Habitat:                         Woodland and wayside trees  

Substrata:                     Bark, occasionally rocks                      

Growth form:                Corticolous, saxicolous  

Thallus:                  Fruiticose                    

Apothecia:                    Lecanorine, infertile    

BLS identity rating:        Graded 2/5 (visual identification possible with care)

Thallus more or less tufted, erect, typically 3-6cm tall, occasionally sub-pendent to 10cm long; main branches to 1.5mm dia., slightly inflated, somewhat flexible and not easily breakable; short, mostly curved, lateral branches constricted and often annulated with white rings at the point of attachment to the main stems.

Overall colour variable, mainly dull grey-green to pale olive-green, often with a waxy blue tinge, sometimes more green-yellowish, particularly when wet, becoming darker, possibly red-orange when old; the base usually concolourous or paler, very rarely blackened, unlike the similar Usnea subfloridana, which is distinctly blackened near its holdfast; cortex glossy and smooth, often with scattered or clustered isidiomorphs mixed with white punctiform soralia; medulla white.   

Usnea cornuta grows on mossy woodland or wayside trees, particularly those in shaded situations, more rarely on mossy siliceous rocks; widely distributed, but local, most frequent in lowland areas, particularly across the south where it is often the most common Usnea species.

There are a number of somewhat similar, but rather variable, Usnea species that in many instances require careful examination and consideration of both ecological and distributional data for accurate identification. I should be able to find five or six species within my local area, but until I've seen and photographed more specimens, I'm going to be careful. In fact, I was going to label these as 'likely' as I was a little unsure, but I went back to check that they were stretchy and didn't have a black base near the holdfast. They passed the test, so I'm as sure as I can be that the identification is correct.

Hopefully I won’t make any silly errors, but whilst I'm just starting to get interested in these species, it's worth noting that some 'beard lichens' could possibly be mistaken for Evernia or Ramalina species, which also grow as tufts on trees, although in most cases they have a flattened, less branched thallus and lack the flexible, cartilaginous central axis.