Fissurina varieseptata

The thallus forms a continuous crust on bark, 1–5 cm across and about 40–70 μm (micrometres) thick. The surface is smooth to uneven and typically yellowish white. The photobiont (the photosynthetic partner) is a trentepohlioid alga (Trentepohlia-type). In cross-section, the upper cortex is irregular and loosely developed, with an irregular algal layer and clusters of crystals. Individual lirellae are about 0.5–1 mm long and about 0.1 mm wide and high, with a complete thalline margin. The disk is mostly concealed, and the labia are inconspicuous; the thalline margin is yellowish white but becomes yellow-brown along the slit. Microscopically, the asci are fusiform and produce eight ellipsoid ascospores. The spores are usually (3–)5–7-septate (divided by internal walls), 12–18 × 4–5 μm, and non-amyloid (I–). No lichen substances were detected by thin-layer chromatography.

The species was originally known only from the type collection from Fakahatchee Strand Preserve State Park in southwestern Florida, where it was recorded growing on hardwood in an old-growth cypress swamp at Big Cypress Bend. It was later documented on arborescent runner oak (Quercus pumila) in Miami-Dade County.

== References ==