J. Hattori Bot. Lab. No. 82: 305- 320 (July 1997) MOSSES OF QINGHAI-TIBETAN PLATEAU, CHINA 1 2 BENITO C. TAN AND JIA Yu ABSTRACT . A total of 57 genera and 109 species of mosses are reported based on collections made from the 1995 expedition to Yushu Prefecture of Qinghai province. Didymodon gaochienii and Or­ thomitrium schofieldii are described new to science. Encalypta intermedia, Hygrohypnum po/are and Leptopterygynandrum austro-alpinum are three moss records that have not previously been reported from China. Significant range extensions . are reported for Amblyodon dealbatum, Conardia compacta, Distichium hagenii, Grimmia anodon, Leptopterygynandrum subintegrum, Oedipodium gri.ffithianum, Orthotrichum pumilum, Philonotis calcarea, Plagiobryum demissum and Pylaisiella falcata . In addition, four new synonyms are proposed with their respective accepted names placed in­ side brackets: Aloina rubripila Aziz & Vohra [ =Aloina rigida var. obliquifolia (C. Muell.) Delgad.], Barbu/a anserino-capitata X.-J. Li [=Didymodonjohansenii (Williams) Zand.], Barbu/a longicosta­ ta X-J. Li [=Didymodon constrictus var. jlexicaulis (Chen) Saito] and Tortu/a longimucronata X.-J. Li [=Syntrichia ruralis (Hedw.) Web. & Mohr]. INTRODUCTION The province of Qinghai, with an area of about 720,000 sq. km, is the fourth largest province in China. It consitutes the eastern flank of the massive Tibetan plateau. The nu­ merous mountain glaciers in the province form the headwater of many great river systems in China and Indochina, such as Yellow River, Yangtze River and Mekong River. Because of its great distance from the ocean, the prevailing climate is strongly continental with in­ tense diurnal changes of daily temperature and a long winter season. The annual precipita­ tion ranges 16.6-624.4ml. The provincial moss flora, with only 4 species reported in litera­ ture, is the least known among all the provinces in China. Redfearn, Tan and He (1996) listed Encalypta ciliata, E. rhadocarpa, Myurella tenerrima and Ptychomitrium dentatum for Qinghai Province. The study area, Yushu Tibetan Autonomous Prefecture (map 1), lies in the southern margin of Qinghai province bordering Sichuan and Xizang. The localities surveyed belong to three adjacent xian/counties: Chengduo (vicinity of Xiewu), Yushu (vicinity of Upper and Lower Batang), and Nangqian (vicinity of Lower and Upper Laxiu, and between the towns of Nangqian and Dongba). One day was spent collecting bryophytes from the marshy shore ofLongbao-tan or the Ron-Po Lake Black-Neck Crane Reservation in Yushu Xian. Nearly all places visited are inhabited by herding nomads, largely Tibetans. There is some cultivation around town settlements and river banks at lower elevations. Signs of ex­ cessive use of the prairie by the local people and their large number of grazing yaks, sheeps and horses are very apparent. The overall landscape of Yushu Prefecture is mountainous, averaging above 4,000 m elevation, and consists of many craggy peaks and mountain passes. Average yearly temper- 1 Farlow Herbarium, Harvard University, 22 Divinity Avenue, Cambridge, MA 02138, U.S.A. 2 The Herbarium, Institute of Botany, Academia Sinica, Xiangshan, Beijing 100093, China. 306 J. Hattori Bot. Lab. No. 82 I 9 9 7 Map 1. Map of China showing the position of Qinghai Province. The solid triangle indicates the location of Yushu Prefecture. ature is between l- 2°C. Since the area receives relatively high yearly precipitation between 400-550ml., the terrain is dissected deeply by many river systems. The existing natural vegetations consist of alpine screes and scrubs, wet meadows, riparian woodlands, and semi-arid wastelands. Patches of arboreal Betu/a, Larix, Picea, Pinus, Populus, Sabina and shrubby Caragana, Rhododendron, Sa/ix and Berberis are scattered along protected slopes and valleys. Important and common herbaceous ground taxa includes Al/ium, Artemisia, Astragalus, Ephedra, Kobresia, Incarvi//ea, Pedicularis, Primula, Saxifraga, Saussurea, Stipa, ground orchids, sedges and grasses. Because of the prevailing arid and cold continental climate, bryophytes are inconspic­ uous and often small in quantity. Surprisingly, we found more than a hundred species of mosses among the ea 250 collections made by the senior author during the summer of 1995 (June 17- July 5). Most species are widespread circumpolar taxa. Enca/ypta intermedia, Hygrohypnum po/are and Leptopterygynandrum austro-alpinum are three mosses reported new to China (indicated below by *). Other Qinghai novelties derived from this expedition include Crossidium crassinerve, C. seriatum, Grimmia obtusifo/ia, Grimmia subanodon, Hilpertia velenovskyi and Schistidium chenii (see also Tan and Zhao, 1997). In addition, Qinghai records of Amblyodon dea/batum, Conardia compacta, Distichium hagenii, Grim­ mia anodon, Leptopterygynandrum subintegrum, Oedipodium griffithianum, Orthotrichum pumilum, Phi/onotis ca/carea, Plagiobryum demissum and Pylaisiella falcata represent siginificant range extension of uncommon and rare species in China. In some cases, correc­ tion of erroneous distribution records are attempted for a few species. The overall ftoristic affinity of Qinghai mosses can now be confirmed to be primarily with the adjacent provinces of Xinjiang, Xizang (Tibet), and Inner Mongolia of China, and secondarily, with Central Asia, Russian Altai and Siberia. Significantly, we collected two remarkable species, Didymodon gaochienii and Or- B. C. TAN & J. Yu : Mosses of Qinghai-Tibetan Plateau, China 307 thomitrium schofieldii, both previously unrecognized. The latter represents the second species of a new Chinese endemic genus described by Lewinsky and Crosby in 1996. It ap­ pears that the rising Qinghai-Tibetan Plateau has served as a new center of plant speciation during the Quartemary in spite of the arid and cold environmemt not favorable to plant growth (Wu, 1995). The present discovery of two new moss species and previous reports of endemic flowering plants in Qinghai, notably the monotypic Sinodoxa coryda/ifo/ia (C.-Y. Wu, Z.-L. Wu and Huang, 1981), supports this contention. Equally noteworthy, A/oina rubripila Aziz & Vohra [=Alo in a rigida var. obliquifolia (C. Muell.) Delgad.], Barbu/a anserino-capitata [ =Didymodon johansenii (Williams) Zand.], Barbu/a /ongicostata X-1. Li [=Didymodon constrictus var. jiexicau/is (Chen) Saito] and Tortu/a /ongimucronata X.-1. Li [=Syntrichia rura/is (Hedw.) Web. & Mohr] are proposed as new synonyms. Since the study area constitutes part of the extensive calcareous Qinghai-Tibetan plateau, many of the mosses encountered are widespread species of calciphilous genera, e.g., Encalypta, Gymnostomum, Cratoneuron and Tortel/a . Others are drought resistant or xeric mosses belong to Pottiaceae and Grimmiaceae, e.g., Alaina rigida, Crossidium crassinerve, Jaffee/iobryum latifolium, Indusiel/a thianshanica and Hilpertia velenoskyi. They either have a broad continental Asiatic or circumboreal range. Conversely, Andreaea, Sphagnum and other acidophilous mosses are non-existent. For reasons not clear to us, spe­ ciose genera, like Drepanocladus, Polytrichum, Racomitrium and Fissidens, are represent­ ed in the study area by single species. The genera Brachythecium, Encalypta, Grimmia and Orthotrichum are among the few genera with five or more species. Interestingly, the Qinghai mosses reveals a tenuous floristic connection with the tem­ perate floras of eastern Himalayan and Sichuan-Yunnan regions. This is shown by the pres­ ence of Orthotrichum cal/istomum and 0. hookeri in protected valleys at lower elevations. These species probably represent relicts of a past temperate flora that was widespread on Asia continent, reaching probably as far north as the Altai region. The upliftment of the Ti­ betan plateau during the Quarternary has caused a drastic change of the prevailing climatic pattern and the aridification of the highlands (Peng and Chen, 1993). Below we present the first report of Qinghai-Tibetan mosses with pertinent taxonomic comments and synonyms. In our list we enumerate 57 genera, 109 species and 6 varieties. Of the four Qinghai mosses reported earlier in literature (Redfearn et al. 1996), Myurel/a tenerrima and Ptychomitrium dentatum have not been recollected. Since the moss flora of Qinghai was virtually unknown before, nearly all of the species reported below are new to the province. Even though the study area represents less than 1110 of the entire province, the final tally of Qinghai mosses will probably increase only by 25% when the entire province is investigated for its moss diversity and distribution because it is predominantly an arid and cold environment. All specimens cited are preserved at FH and PE, and dupli­ cates will be distributed to other herbaria. LIST OF QINGHAI MOSSES STUDIED Abietinella abietina (Hedw.) Fleisch. - on boulder and shaded ground, Nangqian, Yushu [Tan 95- 1639, 95-1641, 95-1643, 95-1644, 95-1645b, 95-1646, 95-2018). 308 J. Hattori Bot. Lab. No. 82 I 9 9 7 Aloina brevirostris (Hook. & Grev.) Kindb. - on dry calcareous soil, mortar walls, Yushu [Tan 95- 1700a, 95-1701, 95-1721]. The taxonomic differences in the leaf morphology between this species and A. rigida can at times become quantitative, rather than qualitative, as observed by Crum and Anderson (1989). In the study area, both species are equally common and often grow­ ing intermixed. Aloina rigida (Hedw.) Limpr. - on soil bank and grassy sod wall, Nangqian [Tan 95-1698a, 95-1699, 95-1702, 95-1721, 95-1724, 95-1934]. Aloina rigida var. ob/iquifolia