Rinodina colobina
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| Rinodina colobina | |
|---|---|
Scientific classification  | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Caliciales |
| Family: | Physciaceae |
| Genus: | Rinodina |
| Species: | R. colobina |
| Binomial name | |
| Rinodina colobina | |
| Synonyms[1] | |
| |
Rinodina colobina is a species of corticolous (bark-dwelling) crustose lichen in the family Physciaceae. It has a dark grey, granular appearance and typically grows on nutrient-rich bark of deciduous trees, including elm, maple, and oak. The lichen is characterised by small black reproductive structures (apothecia) surrounded by a grey margin. It is widely distributed across Europe and North America, favouring areas with consistently high humidity levels.
Rinodina colobina is a crustose lichen characterised by its thin, dark grey thallus (the main body of the lichen) that typically appears granular or with small cracks. The thallus lacks a visible hypothallus (the underlying fungal layer).[2]
The apothecia (reproductive structures) are sessile, meaning they sit on top of the thallus rather than being immersed, and measure 0.35–0.45 mm in diameter. They are relatively sparse and rarely touch each other. The disc of the apothecium is black and becomes slightly convex as it matures. The margin around the disc matches the colour of the thallus or appears somewhat lighter, measuring approximately 0.05 mm in width. This margin is smooth-edged and persists as the lichen develops.[2]
One of the most distinctive features of Rinodina colobina is its blue-black epithecium (the uppermost layer of the apothecium), which reacts positively with potassium hydroxide solution (K+) and nitric acid (N+) to produce a violet colour. This characteristic helps distinguish it from other similar Rinodina species.[2]
The spores are polarilocular (with thickened walls and two chambers) and thick-walled, measuring 12.5–23.5 μm long by 5.0–11.5 μm wide. The outer wall of the spore is thick, and the septum (dividing partition) develops late in the spore's maturation.[2]
