The
thallus of
Fissurina karnatakensis is brown and slightly glossy, with a smooth to uneven texture with cracks. The periphery of the thallus is delimited by a thin, black region. The
ascomata, or fruiting bodies, are in form and immersed, matching the colour of the thallus. They can be simple or branched, measuring 1–6 mm in length and 0.25 mm in width. The is not visible and very narrow, with a slit-like appearance. The is often separated by a narrow slit from the . The exciple is non-striate and present at the base, with a pale orange-brown colour. It is non- and covered by a distinct layer. The
hymenium, a layer containing the
asci, is 105–113
μm high. are approximately 1 μm thick, with hyaline, distinctly warty tips. are short to moderately long and distinctly warty. The asci are 8-spored, and the , which measure 14–21 by 3–5 μm with a 1–1.6 μm-thick , contain 3 transverse
septa. Chemical
spot tests reveal that
Fissurina karnatakensis has K+ (yellow), C−, KC−, P+ (rust-red), and UV− reactions. It contains
protocetraric and
fumarprotocetraric acids, which
lichen products that are rare in the family
Graphidaceae.
Fissurina karnatakensis features the "comparilis-type" ascomatal structure and is distinct from other species like
Fissurina verrucosa due to its exciple, which often has 2 striae (grooves), smaller ascospores (7–12 μm long), and a thallus. ==References==