Fissurina microcarpa is a little-known species of corticolous (bark-dwelling) script lichen in the family Graphidaceae.[1] Described in 2012 from specimens collected in the Western Ghats of southern India, this lichen is distinguished by its exceptionally small, cinnamon-brown fruiting structures and unusual spores. Unlike most related species that produce eight spores per reproductive cell, this lichen produces only a single large spore divided into many brick-like compartments. It grows on tree bark in humid hill forests and is known only from two locations in Tamil Nadu and Karnataka.
The thallus of F.microcarpa forms a brown, glossy crust that becomes cracked and warted as it ages. Across this surface develop plentiful lirellae: minute, cinnamon-brown fissures measuring 0.1–0.4mm long that may stay simple or fork into short branches. Each lirella is immersed at first, then rises slightly as the surrounding cortex swells and splits; its walls (the exciple ) are pale orange-brown and lack the blackened carbon layer ( carbonisation ) seen in some relatives.[2]
Internally the colourless hymenium (spore-producing tissue) stands 112–150μm tall, and the asci are distinctive in containing a single ascospore rather than the usual eight. That spore is large (87–125μm long), muriform —divided into many brick-like chambers by both cross-wise and length-wise septa—and wrapped in a gelatinous halo 5–8μm thick that becomes visible in water mounts. Chemical spot tests show the presence of stictic acid; this secondary metabolite helps separate the species from superficially similar taxa that lack lichen products.[2]
Habitat and distribution
Fissurina microcarpa is known only from two localities in the central and southern Western Ghats of India: the type locality at Upper Kodayar, Tamil Nadu, and an additional site near Sringeri–Balehonnur in Karnataka. Both lie within humid evergreen or semi-evergreen hill forests that receive heavy monsoon rainfall. The lichen grows on the bark of living trees in shaded, mossy situations.[2]
1 2 3 4 Sharma, B.O.; Khadilkar, P.; Makhija, U. (2012). "New species and new combinations in the lichen genera Fissurina and Hemithecium from India". The Lichenologist. 44 (3): 339–362. doi:10.1017/S0024282911000752.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
