Fissurina tuckermaniana
Fissurina tuckermaniana is a lichen that forms a thin, crust-like growth on bark and belongs to the family Graphidaceae. It is known from subtropical Florida. It has fissure-like, darkened and unusually large ascospores with three septa, produced in low numbers in each ascus. It also has paraphyses and.
Taxonomy
The species was described as new in 2011 by Ralph Common and Robert Lücking. The holotype was collected in April 1997 in Fakahatchee Strand Preserve State Park, along the Scenic Drive near gate 14 in a second-growth area. It is deposited in the herbarium of the Michigan State University Museum.The epithet tuckermaniana honors Edward Tuckerman, in recognition of his contributions to North American lichenology. The species resembles Fissurina comparilis and Fissurina comparimuralis in overall appearance, but it can be separated by microscopic features, especially the large 3-septate spores and the spiny structures in the hymenium.
Description
The thallus forms a crust on bark, typically 1–2 cm across and about 30–50 μm thick. It forms a continuous crust with a smooth surface that is yellowish-brown to olive-brown and contains a photobiont. In cross-section, the thallus has a upper, an irregular, and scattered clusters of crystals.The lirellae are straight to curved and usually unbranched, ranging from immersed to slightly. Individual lirellae are about 1–3 mm long and 0.3–0.5 mm wide, with a complete thalline margin; the disk is concealed. The are conspicuous but not thickened, appearing greyish black to brown-black beneath the corticate. The is also darkened. Microscopically, the asci are and contain 2–4 ellipsoid ascospores. The spores are 3-septate, about 25–40 × 11–14 μm, and amyloid. Paraphyses and periphysoids are present, with spinulose tips. No lichen substances were detected by thin-layer chromatography.