Fissurina khasiana is a species of corticolous (bark-dwelling) script lichen in the family Graphidaceae. It is found in India, specifically in the evergreen forests of Upper Shillong in the Khasi Hills; its species name is derived from the region where it was first collected. The lichen was formally described as a new species in 2007 by Urmila Makhija and Bharati Adawadkar.
The thallus of Fissurina khasiana is greyish-green in colour, with a smooth and cracked surface that appears . Its ascomata, or fruiting bodies, are in form and measure 2âÂÂ4 mm in length and 0.1 mm in width. They can be simple or irregularly branched, immersed, and end in a sharp or somewhat acute tip. The of the ascomata is narrow, black, and indistinct. The is present at the base, non-striate, and non-, with a round and somewhat puffed appearance. It is mostly convergent to slightly divergent and covered by a up to the top.
The hymenium is hyaline, not , and ranges from 80 to 100 üm in height. The is also hyaline. are simple, long, and thin, with slightly elongate, warty tips. are short and mostly smooth, occasionally having warty tips. Asci are cylindrical, 6âÂÂ8-spored, and measure 50âÂÂ60 by 6âÂÂ8 üm. The ascospores are ellipsoidal with 3 transverse septa, and measure 16âÂÂ19 by 8âÂÂ10 üm and a 1.6âÂÂ2 üm-thick .
Chemical spot tests reveal that the thallus of Fissurina khasiana has K+ (yellow-red), CâÂÂ, KCâÂÂ, P+ (orange), and UVâ reactions. The lichen contains both constictic and stictic acids. The ascomatal structure of the species is considered to be of the "comparilis-type." However, Fissurina khasiana is distinct from other species in this group due to the presence of both stictic and constictic acids in its thallus.
Fissurina khasiana has an ascomatal structure that is intermediate between Fissurina inquinata and F. triticea. It is distinguished by its relatively minor "puffing" and a non-carbonized exciple, setting it apart from both F. inquinata, which has little "puffing" and a carbonized exciple, and F. triticea, which has strongly "puffed" ascomata and a non-carbonized exciple. Additionally, Fissurina triticea has larger and more rounded ascospores, measuring 15âÂÂ20 by 10âÂÂ15 üm.