Mushroom

In a lichen, a fungus associates with an alga or cyanobacterium capable of photosynthesis. The photosynthetic partner provides nutrients; the fungus helps protect it from drying and radiation.

The University of Évora describes crustose, foliose and fruticose forms, among others. This offers a new way to notice surfaces and textures without confusing colour with identification. This story explains lichen biology; it is not an inventory of species confirmed in Cabeceiras.

Reproduction can carry the partnership too: lichen fragments can disperse both partners together. By contrast, the fungus’s spores need to encounter a photosynthetic partner to form a new lichen.

The shapes can resemble a crust, divided leaves or small shrubs. These words describe appearance, with boundaries that are not always rigid. Lichens are not mosses either: mosses are plants, whereas lichens are classified with fungi.

The growing surface deserves attention too: lichens may grow on rocks, bark, soil and artificial surfaces. The University of Évora explains that identification combines appearance with substrate and habitat; sometimes it requires microscopy or other specialist methods. A photograph can record the encounter without resolving the name.

Another aspect is the study of air. Lichens can accumulate compounds from the atmosphere and are used as bioindicators or biomonitors. A patch on a wall cannot, by itself, classify a village’s air quality. That conclusion requires a suitable study, just as assessing a river combines different observations.