Introduction
The genus Pertusaria DC. is widespread, with over 520 species worldwide (Kirk et al. Reference Kirk, Cannon, Minter and Stalpers2008). Its morphology is remarkably variable. The chemistry of the genus is very complex and is of particular value in the identification of taxa (Archer Reference Archer1997), and molecular data also support secondary chemistry as an important character in the classification of the Pertusariaceae (Schmitt & Lumbsch Reference Schmitt and Lumbsch2004).
In 1991, 54 Pertusaria taxa (including 44 species, 9 varieties and 1 form) were reported from China (Wei Reference Wei1991). Despite an increased number of studies on the genus Pertusaria from China in recent years, there is still no up to date information on this genus from Xinjiang Uygur Autonomous Region in Western China. Recent examination of Chinese specimens has revealed a new saxicolous species, described here as Pertusaria weii Q. Ren, which is recorded from the Tianshan Mountains in Western China. The new taxon superficially resembles P. qilianensis Q. Ren & Z. T. Zhao, but differs in the number of ascospores per ascus, and in chemistry and habitat (Ren et al. Reference Ren, Sun and Zhao2008).
Materials and Methods
Specimens were collected from calcareous rock in the Tianshan Mountains, Western China, and are deposited in SDNU (Lichen Section of the Botanical Herbarium, Shandong Normal University). The morphology of the lichen specimens was examined using an Olympus SZ 51 stereomicroscope. Hand-cut sections were examined with an Olympus CX 21 compound microscope. Photographs of the thallus were taken with an OLYMPUS SZX16 camera with DP72, and photographs of ascospores were taken using an OLYMPUS BX61 with DP72. Measurements of well-developed ascospores lying outside the asci were made on material mounted in 10% KOH (K). Colour reactions (spot tests) were carried out using standard methods (Orange et al. Reference Orange, James and White2001). Chemical constituents were identified using thin-layer chromatography (TLC) (Culberson Reference Culberson1972).
The Species
Pertusaria weii Q. Ren sp. nov.
MycoBank No.: MB802450
Similar to Pertusaria qilianensis, but differs in the number of ascospores per ascus, chemistry and habitat.
Type: China, Xinjiang, Urumqi, Tianshan Mountains, Glacier No.1 at the headwaters of Urumqi River, alt. 3500 m, on calcareous rock, 27 August 2011, Li Lin 20125913 (SDNU—holotype).
(Fig. 1)
Fig. 1. Pertusraia weii Q. Ren. A, thallus showing margin; B, thallus showing fertile verruca; C, cross-section of apothecium; D, ascus with one spore (Li Lin 20125913). Scales: A & B=2 mm; C=100 µm; D=50 µm. In colour online.
Thallus crustose, epilithic, whitish grey to brownish grey, continuous to fissured or fissured-areolate, thin to moderately thick, lacking soredia or isidia, margins entire and unzoned. Surface initially tuberculate, later heavily rugose-plicate, matt, epruinose. Fertile verrucae lecanorine and concolorous with thallus, numerous, solitary, c. (0·5–) 1·0–1·5(–2·0) mm diam., the verrucal margin always lacerate. Disc grey to black, sunken to level, generally covered by heavy, white or greyish pruina.
Apothecia 1 per verruca. Hypothecium brownish. Epithecium dark brown to black, K+ violet. Hymenium hyaline. Paraphysoids reticulate, branched. Asci cylindrical, 1-spored, IKI+ blue-green to black. Ascospores hyaline, non-septate, ellipsoid to ovoid, K−, 150·0–192·5×67·5–82·5 µm; spore walls smooth, not trimmed, c. 2·5–7·5 µm thick, 1-layered.
Pycnidia not seen.
Chemistry
Cortex all chemical tests negative, UV−; medulla K+ yellow, C−, KC−, Pd+ orange. Major substance: stictic acid.
Etymology
The new species is named after Jiangchun Wei, a founder of lichenology in China, who has made outstanding contributions to the development of lichenology over recent decades.
Habitat and distribution
The new species grows on calcareous rock at an elevation of 3500 m. It is known only from the type locality.
Notes
Pertusaria weii is rare in the Tianshan Mountains of Xinjiang Uygur Autonomous Region. This species has β-orcinol depsidone (stictic acid), lacks chlorinated xanthones, and has disciform apothecia and 1- spored asci with single-walled ascospores. The above characters indicate that this new species belongs to the Variolaria group of the Pertusariaceae (Schmitt & Lumbsch Reference Schmitt and Lumbsch2004).
Diagnostic characters for the species are a brownish thallus, apothecia somewhat verruciform at first becoming disciform at maturity, asci with one ascospore and stictic acid as the major lichen substance. It superficially resembles the lignicolous P. qilianensis, which occurs in the western areas of China. Pertusaria qilianensis contains planaic acid, has 2 spores per ascus and grows on rotten wood.
Specimen examined. China: Xinjiang: Urumqi, Tianshan Mountains, Glacier No.1 at the headwaters of Urumqi River, alt. 3500 m, on calcareous rock, 2011, Li Lin 20125916 (SDNU).
Financial support from the National Natural Science Foundation of China (31100011 & 31093440) is greatly appreciated.
