Halecania pakistanica
Halecania pakistanica is a species of crustose lichen in the family Leprocaulaceae. The lichen forms irregular patches of small, closely packed angular segments with a pale brown to greyish-brown upper surface and scattered fruiting bodies up to 1 mm across. It grows on exposed limestone rocks at high elevations in the Karakoram mountains of northern Pakistan, where it was discovered at about 3,620 m elevation. As of 2012, it remained the only species of its genus recorded from Pakistan.
Taxonomy
Halecania pakistanica was described as a new species in 2005 by Pieter van den Boom and John Elix. The description was based on material collected in 1991 from calcareous rock in the Rakaposhi-Haramosh Mountains at an elevation of about 3,620 m; this collection serves as the holotype.Description
The thallus of Halecania pakistanica is crustose and distinctly, forming irregular patches composed of small angular to rounded about 0.2–1 mm across and up to about 0.3 mm thick. The areoles are usually closely packed, sometimes with their margins slightly raised or upturned, giving the surface a rough, uneven to weakly granular appearance. The upper surface is matt and pale brown, grey-brown or yellowish brown, and lacks a differentiated or. Algal cells are scattered throughout the thallus rather than concentrated in a discrete layer, and a dark brown to blackish is often visible around the margin.Apothecia are common and range from about 0.2 to 1 mm in diameter, at first slightly immersed but soon broadly and usually scattered on the thallus. The is mid- to dark brown, becoming paler and reddish brown when wet, and is plane to weakly concave when young, later becoming slightly convex; it lacks. A thin, scalloped develops in mature apothecia, the same colour as the thallus and remaining persistent. In section, the hymenium is about 50–60 μm tall and hyaline, overlain by a brown to red-brown that does not react with K or N. The is relatively high and hyaline. Paraphyses are stuck together, only slightly thickened towards the tips, and have apical cells with brownish-black walls. Asci are of the Catillaria type, narrowly club-shaped, 8-spored, and have a uniformly amyloid apical dome when stained in iodine. Ascospores are oblong-ellipsoid to ellipsoid, typically 10–12 × 4–6.5 μm, 1-septate, thin-walled and surrounded by a distinct gelatinous halo that swells in potassium hydroxide solution and may be thickened at the septum. Pycnidia are infrequent, immersed and inconspicuous; the conidia are, short spores about 2.5–3 μm long. No lichen secondary metabolites have been detected by thin-layer chromatography or high-performance liquid chromatography, and standard spot tests are negative.