Wednesday, 14 June 2017

Yellow, widespread and strong

Xanthoria parietina is a yellowy orange colored leafy lichen that is one of the most common species around. The yellow chemical xanthorin is thought to be produced as a defense against UV radiation to which it is exposed in its normal habitat like cement tiled roofs, exposed twigs and branches etc.
When it is growing in the shade it does not require such protection and xanthorin production stops and the lichen remains green. In or after rain, this lichen appears more greenly yellow as the algae shows through the more translucent fungus.

It grows on rocks or walls (hence the epithet parietina meaning "on walls"), cement, tiled roofs and tree bark, particularly where bird droppings fall and it can be seen all year round. Xanthoria parietina is a very pollution-tolerant species. Nutrient enrichment by bird droppings enhances the ability of X. parietina to grow on rock. In the past it was used as a remedy for jaundice.

No comments:

Post a Comment