Fissurina disposita

The thallus forms a pale- to mid-brown, glossy crust that soon becomes cracked, flaking and slightly warty (verrucose). Its margin is outlined by a thin, dark hypothallus. Numerous lirellae – minute slit-like fruit bodies – are scattered across the surface; each is 0.2–0.5 mm long, straight to gently curved, crowded, and terminates in an acute tip. The lirellae sit flush with the thallus at first and rise only slightly as the cortex swells and splits around them. Their walls (the exciple) remain pale rather than developing the thick black melanin layer typical of many other script lichens.^[2]

Under the microscope the colourless hymenium produces a single ascospore in each ascus. Spores are hyaline, somewhat muriform—divided into brick-like chambers by three to four cross-walls and one or two longitudinal septa—and measure 10–12 × 5–6 μm. No lichen secondary metabolites were detected in the original collections.^[2]

All confirmed records of F. disposita fall within the wetter reaches of the Indian peninsula. The type locality at Cherrapunji lies in one of the world's rainiest subtropical hill forests, while shola forests in Karnataka provide a cooler, mist-laden refuge farther south. In both regions the lichen grows on the smooth bark of living trees in shaded, undisturbed woodland where high humidity and heavy monsoon rainfall prevail.^[2]