… by genus: Leptogium
Greek: leptos = thin, referring to the paper thin thallus when they are dry. The thallus is foliose and sometimes almost crustose or even micro-fruticose. They are gelatinous when wet. Apothecia are the usual method of reproduction; they have a thalline coloured margin. The spores are colourless, 3 – 5 septate. No lichen substances are present; consequently all the standard chemical reactions are negative. The photobiont is a cyanobacterium of the genus Nostoc. Generally found on bark, soil, rocks and among mosses. Their colours fall into the range of dark grey to green-blue.