Kind people in the ‘Lichens connecting people’ group I’ve joined on Facebook have been helping me identify some of the other lichens we found in the Kashmir and Ladakh (see ‘More Weird and Wonderful Lichens’). I’m not absolutely convinced about the suggestion that this odd looking specimen, which we found at the Chang La pass (5360 m), is Umbilicaria cylindrical, though I’d managed to get it as far as genus level myself so was pleased to find I was on the right track. However, though the underside of the thallus is covered in rhizinomorphs (root-like outgrowths of the fungal filaments), this lichen doesn’t have the fringe of fibrils which characterise U. cylindrica.
Umbilicaria sp. growing at 5360 m
The genus has two common names – rock tripe and navel lichen. Some species are apparently edible when properly prepared; U. esculenta is a delicacy in Korea and Japan and desperate Arctic explorers have apparently used species found there as a survival food. Rather them than me – it appeals no more than its namesake! Each thallus of the lichen is attached to the rock surface at just a single, central point (the umbilicus of the scientific name). You can see these in the photo above, along with the black fruiting bodies (apothecia) on the upper surface. Umbilicaria has a preference for acid rocks as a substrate, so its presence on granite boulders at Chang La is not surprising.
Growing alongside the Umbilicaria at Chang La we also found the grey-green thallus of Rhizoplaca melanophthalma. This distinctive-looking species is very widely distributed in Arctic/Antarctic regions and elsewhere at high altitudes and has been used in biomonitoring studies in the USA. Its growth is sufficiently sensitive that it can be used as an indicator of the amount of aerial deposition of heavy metals which is going on, near places such as refineries (Dillman, 1996). I’m a little puzzled by the ‘melanophthalma’ specific name (‘black eye’ in Greek) but assume it refers to the black interior of the abundant apothecia.
Rhizoplaca melanophthalma, also at Chang La
The black, crustose lichen below, which we also found at Chang La, is a species of Acarospora, I am told. These lichens are generally found in open, arid habitats. It’s not difficult to see why they are commonly called cobblestone lichens.
Like other crustose lichens, the algal cells (the phycobiont) are sandwiched between two layers of fungal material – the cortex above and the more loosely-packed hyphae of the medulla below. In these lichens, the spore-producing apothecia tend to be difficult to spot, embedded as they are in the thallus.
The final lichen my friends helped me identify as Lecanora muralis is much more familiar looking. We found this species, also native to the UK, at lower altitudes (around 3000 m) in Kashmir. Although its fungal partner is very similar to that of Rhizoplaca, this Lecanora species is so pollution tolerant that it is often found growing on pavements in the UK, where it can be easily mistaken for discarded chewing gum. Rather a comedown for a species whose generic name comes from the Greek for ‘beautiful small bowl’, after the shape of its apothecia!
Lecanora muralis in Kashmir
And on the pavement in Bowburn, County Durham
Dillman K.L. (1996). Use of the lichen Rhizoplaca melanophthalma as a biomonitor in relation to phosphate refineries near Pocatello, Idaho. Environmental Pollution, 92, 91-96