Ditrichopsis wui(Ditrichaceae,Bryophyta): A New Species from Xinjiang of China?

MAIMAITIMING Sulayman,DILIHUMAER Abudukeremu,SHANG Shuaibin,ZULIMIRE Maimaitiyiming

(1. Xinjiang Key Laboratory of Biological Resources and Genetic Engineering,School of Life Science and Technology,Xinjiang University,Urumqi Xinjiang 830017,China;2. Northwest Surveying,Planning and Designing Institute,National Forestry and Grassland Administration,Xi’an Shaanxi 710048,China)

Abstract: Up to date,Ditrichopsis Broth. contains three species worldwide,Ditrichopsis wui M.Sulayman as a new species was found by the author during the recent studies from Tianshan Mountains, Xinjiang of China. Its main characteristics are:(1) Leaves are ovate to oblong-ovate, with a long costa and contorted at leaf apex; (2) Leaf cells are short rectangular to long rectangular, thin-walled; (3) Cylindrical capsules are cleistocarpous, abruptly contracted to an erect long beak at the apex; (4)Calyptras are cucullate,large,covering the whole capsule;(5)Spores are small,9～12 μm in diameter. Its habitat shows that the extreme climate might affect its physiological and morphological adaptive traits.

Key words: Bryophyta;Ditrichaceae;Ditrichopsis;Ditrichopsis wui M.Sulayman,sp. nov.;new species

0 Introduction

The genusDitrichopsisBroth. belonging to Ditrichaceae,endemic to East Asia,was established in 1924 by Brotherus,and its type speciesD.gymnostomaBroth. without peristome teeth[1]. There are only three species described in the genus so far,including the other two species:D.clausaBroth. with cleistocarpous capsules from China[2-5]andD.baikalensisfrom southern Siberia, Russia[6]. In recent years, during the floristic investigation in Tianshan Mountains, Xinjiang of China, the authors collected some small mosses with many capsules on moist rocks at the elevation of 3 400～3 750 m above sea level.Their leaves are similar to those ofBryum,but its capsules are cleistocarpous and abruptly contracted to an erect long beak at the apex. Thus it indicates that this is a member ofDitrichopsis. The new species,DitrichopsiswuiM.Sulayman is described as follows.

1 Results

1.1 Description(Fig 1～Fig 2)

Plants small gregarious or loosely to densely tufted,yellow to brownish,slightly glossy. Stems erect,2.5～4 mm long,with a central strand including 1～2 layers of small thick-walled cortical cells and 10～12 large thin-walled cells. Leaves erect when dry and flexuose when wet,1.2～1.8 mm long,0.6～1.2 mm wide,slightly distorted near the apex,from oblongovate base to a narrow, long triangular acumen, margins entire, flat, sometimes incurved in the middle; Costa slender and long, occupying ca. 1/3 width of leaf base, gradually filling the leaf acumen; Lamina unistratose, upper laminal cells short rectangular or nearly quadrate,(17～30)μm×(25～60)μm,cells at leaf shoulder long rectangular,thin-walled,basal lamina cells long rectangular,(16～25)μm×(30～70)μm,thin-walled. Seta light brownish,2～3 mm long,straight. Capsules erect,cylindric,light brown,cleistocarpous,abruptly contracted to an erect long beak at the apex,ca. 2 mm long. Calyptra large,cucullate,covering the entire capsule. Spores small,light green,globose,9～12 μm in diameter.

Fig 1 Plants,capsules and spores of Ditrichopsis wui M.Sulayman

Fig 2 Leaves,leaf cells,cross-sections of stem and leaf of Ditrichopsis wui M.Sulayman

1.2 Specimens

The Tianshan Mountains No. 1 Glacier is located at altitude 3 775 m,43?79′62.56″N,86?80′11.63″E,and the type specimen, M. Sulayman 31032, was collected on rock, 9 June 2018[Holotype: XJU!; Isotype: PE!]. Xinjiang of China,Western Tianshan Mountains, Qiaoerma-Haxilegen Daban Nileke County, Ili Prefecture, altitude 3 400 m, 43?43′41″N,81?24′58″E,on soil,4 July 2022,M.Sulayman 36606. [Paratype: XJU!(Herbarium of Xinjiang University);Isoparatype:PE!].

1.3 Etymology

The name of new species is honor to professor WU Pengcheng,a senior bryologist of the Institute of Botany,the Chinese Academy of Sciences,Beijing,in appreciation for his important contribution to the knowledge of bryophytes in China.

1.4 Differentiation

This new species is mainly characterized by the following features: (1)Leaves are ovate to oblong-ovate, with a long costa and contorted at leaf apex;(2)Leaf cells are short rectangular to long rectangular,thin-walled;(3)Cylindrical capsules are cleistocarpous,abruptly contracted to an erect long beak at the apex;(4)Calyptras are cucullate,large,covering the whole capsule. (5)Spores are small,9～12 μm in diameter.

DitrichopsiswuiandD.clausaare closely related species both with cleistocarpus capsules. The former differs from the later mainly by the leaf shape and spore size.D.wuihas leaves from broad oblong-ovate base suddenly to a narrow,long triangular acumen and small spores of 9～12 μm in diameter,whileD.clausahas leaves from long ovate base suddenly narrowed into a long triangular acumen and the large spores of 20～25(30)μm in diameter. The leaf shape ofD.wuiandD.baikalensisare similar with broad bases,but the later has stegocarpous capsules. The differences among four species ofDitrichopsisare shown in Table 1.

Table 1 Comparison of the four species of Ditrichopsis

2 Discussion

2.1 Distribution

Ditrichopsisis one of the East Asiatic endemic genera[7]. Among the genus,D.clausawas known from four localities,in Yunnan and Sichuan of China[2,7], Sikkim in Northeastern India[9]and Zabaikalsky Territory of Southern Siberia, Russia.Up to now,D.gymnostomawas recorded only in one locality from Southwest China[9], whileD.baicalensiswas found at Transbaikalia,Republic of Buryatia,South Siberia,Russia. The new species,D.wui,found in the Western Tianshan Mountains of Xinjiang Uygur Autonomous Region of China,presents the most west distribution to the longitude of 81?24′58″E for the genus.

2.2 Ecology

The collection localities ofD.wuiare Western Tianshan Mountains in Xinjiang of China,including Qiaoerma-Haxilegen Daban, Nileke County, Ili Prefecture, and No. 1 Glacier area, which are located at the middle part of Tianshan Mountains near Shengli Daban,ca. 120 km southeast of Urumqi,with the altitude of 3 400～3 775 m. It is the extreme environment with drought and low temperature in whole year around this region. The summer average precipitation is 277 mm,accounting for 64% of the annual average precipitation. The average temperature is-5.3 ℃,and 0～5 ℃from June to September. Therefore,it is one of the best areas for studying the development,evolution and ecology of alpine tundra of vegetation types in China.The collection localities of the other three species ofDitrichopsis, exceptD.baikalensis, are also distributed between the altitude of 3 000～4 000 m.