# Upretia

Upretia is a genus of lichen-forming fungi in the family Teloschistaceae. It has three species of saxicolous (rock-dwelling), crustose lichens. Upretia is characterised by its small ascospores and narrow, rod-shaped conidia. The distribution of the genus ranges from mid-altitude rocky terrains in India to both arid and higher altitudinal environments in China.

## Taxonomy

Upretia was circumscribed by lichenologists Sergey Kondratyuk, Arne Thell, and Jae-Seoun Hur in 2017, with Upretia amarkantakana assigned as the type species. Upretia is a member of the subfamily Caloplacoideae of the Teloschistaceae. The genus is named in honour of the Indian lichenologist Dalip Kumar Upreti, recognising his contributions to the study of Indian lichens.
Its closest relative, the monotypic genus Ioplaca from the eastern Himalayas, is differentiated by its thallus colour, areolae structure, and apothecia.

## Description

The genus Upretia is characterized by a crustose thallus that is typically orbicular in shape and ranges from lobate to somewhat squamulose in form. The central part of the thallus often has a subsquamulose appearance but can sometimes be areolate to verruculose. Its colour varies from olive-grey to brownish grey or ash-grey. The thalline lobes of Upretia are generally narrow to wide, branched, and have a flat to slightly convex surface, often covered with a fine dusting known as pruina.
The outermost layer of the thallus, or cortical layer, is thin and made of tightly interwoven cells (paraplectenchymatous). The uppermost cells in this layer are typically brownish, but there is no distinct epinecral layer. The inner layer of the thallus, or medulla, is white. Both a prothallus and hypothallus are usually present and are characterized by their black colour.
The apothecia of Upretia are lecanorine in form, meaning they have a thalline margin that is the same colour as the thallus. They start as immersed structures in their young stage and become sessile as they mature. The disc of the apothecia ranges in colour from orange to brownish and can be either concave or flat. The true exciple, the layer beneath the thalline margin, also has a paraplectenchymatous structure. The paraphyses, or sterile filaments within the apothecia, contain oil droplets. Each ascus typically contains eight spores. These ascospores are clear (hyaline) and polaribilocular, meaning they are divided into two components (locules) separated by a central septum with a hole. The conidia, or asexual spores, are narrowly bacilliform (rod-shaped) and small.
Upretia shows no colour change when exposed to potassium hydroxide (K−), bleach (C−), or para-phenylenediamine (Pd−) chemical spot tests. However, the apothecium disc and epihymenium react with potassium hydroxide to turn purple, while not reacting to bleach or para-phenylenediamine. The presence of parietin and an olive spot at RF class 4 has been noted in the apothecial disc, based on previous research.

## Habitat and distribution

Upretia species grow on rocks in varying environmental conditions and altitudes. Upretia amarkantakana thrives on sun-exposed bauxite rocks. It is found in the Madhya Pradesh region of India, specifically in the Anuppur, Dindori, and Shahdol districts around the Amarkantak area. This species is typically found at altitudes ranging from 500 to 600 m (1,600 to 2,000 ft). It is often found in the company of species from the genera Buellia and Staurothele. Upretia hueana is located in Madhya Pradesh as well, but it is found at a higher altitude, around 1,050 m (3,440 ft). Upretia squamulosa is known to grow in arid environments and has a broader elevation range, from 1,240 to 3,160 m (4,070 to 10,370 ft). Its distribution is limited to Yunnan province in China, marking a significant geographical distinction from its congenera in India.

## Species

* Upretia amarkantakana (Y.Joshi & Upreti) S.Y.Kondr. & A.Thell (2017)
* Upretia hueana (B.de Lesd.) S.Y.Kondr. & Upreti (2020)
* Upretia squamulosa Y.Y.Zhang & Li S.Wang (2019)