Research Article
Research Article
A new propaguliferous species of Pohlia (Mielichhoferiaceae, Bryopsida) from Tibet, China
expand article infoRui-Hong Wang, A. Jonathan Shaw§, Xiao-Ming Shao|, Xiao-Rui Wang
‡ Tibet Agricultural and Animal Husbandry University, Nyingchi, China
§ Duke University, Durham, United States of America
| Agricultural University, Beijing, China
¶ Shijiazhuang University, Shijiazhuang, China
Open Access


A new propaguliferous moss species, Pohlia tibetana X.R.Wang & X.M.Shao (Mielichhoferiaceae), from Tibet, southwest China, is described. The new species differs most saliently from other species of Pohlia by its combination of slender plants, loosely attached leaves and axillary solitary, and dark red and flower-like gemmae. In this paper, the line drawings, photographs, habit of the new species are provided and a morphological comparison of it with the similar species is made.


Asexual reproduction, axillary gemma, Sygera Mountain


Asexual reproduction is a remarkable feature and widespread in bryophytes (Frey and Kürschner 2011). Asexual propagules play important roles when sexual reproduction is not attainable (Imura 1994) and can be produced under more stressful conditions and germinate more rapidly in contrast to spores (Newton and Mishler 1994). Vegetative diaspores may come from caducous fragmentation of gametophytic parts (leaves, leaf apices, shoots, branches and bulbils), specialized propagules (gemmae, protonemal brood cells and tubers) or clonal reproduction (Newton and Mishler 1994; Frey and Kürschner 2011).

A group of species in the genus Pohlia Hedwig (Mielichhoferiaceae Schimp.) produce specialized asexual propagules and the characters of propagule were used to distinguish various species (Cao and Zhao 2009; Liu et al. 2018). The habitat and the gametophyte characters of these species are very similar. Shaw made a taxonomic revision of the propaguliferous species of Pohlia in North America to better identify them (Shaw 1981a). In Czernyadjeva’s (1999) study of propaguliferous Pohlia founded in Russia and adjacent regions, the distribution with maps and habitat preferences of nine species was discussed. A taxonomic and descriptive study of seven propaguliferous species with axillary gemmae of Pohlia in the Iberian Peninsula was made by Guerra (2007). In addition to providing the information on the habitat and distribution, Guerra also gave the photomicrographs of gemmae of each species. Suárez and Schiavone (2011a) meticulously compared the taxonomically important characters of American Pohlia species in habits and morphology of stems, leaves, perichaetial leaves, setae, stomas, peristome and annulus. They revised the propaguliferous species of Pohlia from Central and South America and presented the morphological illustrations and photomicrographs of six species with axillary gemmae and one with rhizoidal tubers (Suárez and Schiavone 2011a).

Liu et al. (2018) presented the taxonomic study of ten species of Pohlia with axillary and rhizoidal propagules in China, including two new records: P. andalusica (Höhn.) Brotherus and P. andrewsii A.J. Shaw. with the photomicrographs of propagules and line drawings were provided. Wang et al. (2020) reported another newly recorded species with axillary gemmae to China from Tibet: Pohlia tundrae A. J. Shaw.

Recently, the authors revised the genus Pohlia in Tibet, China and found a collection different from any species previously known with axillary gemmae. It is characterized by the combination of slender plants, loosely attached leaves and solitary, dark red and flower-like gemmae, and it is here described as a new species.

Materials and methods

Microscopic examination was carried out using traditional methods. The collections of Pohlia and relevant species in the herbarium of Institute of Applied Ecology, Chinese Academy of Sciences (IFP), Kunming Institute of Botany, Chinese Academy of Sciences (KUN), Institute of Botany, the Chinese Academy of Sciences (PE), and China Agricultural University (BAU) were examined.

Authors observed the plants under the dissecting microscope and examined the leaves and gemmae under the compound light microscope. Light micrographs were photographed using a Motic BA210digital microscope. All line drawings were made using the drawing tube attachments of these optical microscopes.

Taxonomic account

Pohlia tibetana X.R.Wang & X.M.Shao, sp. nov.

Figs 1, 2


China. Tibet, Linzhi City, Sygera Mountain, Lulang Town, 29°49'0.96"N, 94°44'27.24"E, 3101 m a.s.l., 4 August 2017, Wei Li & Li-wei Wang 20170804LL010 (holotype: BAU!).


The new species differs most saliently from other species of Pohlia by the combination of slender plants (Figs 1A, 2A), loosely attached leaves (Figs 1A, 2A) and axillary solitary, dark red and flower-like gemmae (Figs 1A, F, 2A, F) (Table 1).

Figure 1. 

Pohlia tibetana. A plant B proximal laminal cells C median laminal cells D apical laminal cells E leaves F gemmae. Drawn by Xiaorui Wang from the holotype (BAU!).

Figure 2. 

Light micrographs of Pohlia tibetana. A plants B leaves C apical laminal cells D median laminal cells E proximal laminal cells F gemmae. Photographed by Xiaorui Wang from the holotype (BAU!).

Table 1.

Morphological comparison of characters distinguishing the similar species in Pohlia with single gemma per leaf axil.

Feature P. tibetana P. inflexa P. filum P. beringiensis P. rabunbaldensis P. drummondii
Plants slender, light green, dull when dry slender to medium-size,, whitish to yellow-green or green, ± glossy when dry slender to medium-size, green to light green, slightly glossy when dry slender, whitish green, glossy when dry slender, green to light green, dull when dry medium-size, dark-green, glossy when dry
shape of gemmae Bulbiform oblong-bulbiform ovoid to eliptical or subglobose bulbiform narrowly bulbiform oblong to cylindrical
color of gemmae yellowish brown to deep cherry-red deep cherry-red orange to orange-brown, or black red to black-red orange or orange-red to reddish dark red-brown
size of gemmae 200–280 μm long >500 μm long 300–500(–550) μm long 500–650(–1000) μm long 400–750 mm long 350(500)–1000(1900) μm long
leaf primordia inconspicuous, peglike to broadly somewhat triangular-laminate, at apex as well as below, the same color as the body, incurved conspicuous, broadly lanceolate laminate, at apex and scattered lower on the body, pale to green, erect, somewhat incurved inconspicuous, stiffly and triangular-lanceolate laminate, arising only in the apex and sometimes lower, green to pale, erect conspicuous, stiffly and broadly laminate, at apex and more proximally, whitish green, erect conspicuous, broadly laminate, at apex and lower, sometimes to base, green, flexuose conspicuous, stiffly lanceolate laminate, scattered at the apex and below, green, erect


Plants slender, light green, dull. Stems 0.5–1.2 cm. Leaves spreading, somewhat contorted when dry, lanceolate to ovate-lanceolate, 0.5–1.0 mm long, somewhat decurrent; margins serrulate to serrate in distal 1/2; costa ending 3–5 cells below leaf apices. Distal laminal cells rhomboidal, 35–70 μm long, 7–11 μm wide, walls thin; Median laminal cells linear-rhomboidal, 70–110 μm long, 5–11 μm wide, walls thin. Basal laminal cells rectangular, 23–65 μm long, 9–16 μm wide, walls thin. Axillary gemmae borne singly in upper leaf axils, 200–280 μm long, 140–230 μm wide, yellowish brown to deep cherry-red, opaque, rosebud shaped, with conspicuous, incurved, peglike to broadly triangular laminate leaf primordia scattered on the bulbiform body. Leaf primordia the same color as the body, arising as elongate, peglike outgrowths, but rapidly differentiating to form a laminate appearance. Sporophytes unknown in China populations.


The specific epithet tibetana refers to the type locality in Tibet in southwestern China.

Distribution and habitat

Currently Pohlia tibetana is only known from the type locality. This species grows on loose soil of rocks in the forest of Pinus armandii Franch. It forms tufts mixed with Pohlia flexuosa Harvey, Pohlia hisae T.J.Kop. & J.X.Luo and Calypogeia fissa (L.) Raddi.

Chinese name

西藏丝瓜藓 (xī zàng sī guā xĭan)


Gemmae, arising singly or clustered in the leaf axils, is very common in Pohlia. P. inflexa (Müll. Hal.) Wijk & Margad., P. filum (Schimp.) Mårtensson, P. beringiense A.J. Shaw, P. rabunbaldensis A.J. Shaw and P. drummondii (Müll. Hal.) A.L. Andrews are similar to the new species in the characteristic of having singly axillary gemmae (Shaw 1981a, 1982, 2006, 2015; Shevock and Shaw 2005; Guerra 2007; Uyar and Ören 2013; Wang et al. 2020). The detailed comparisons of plant and gemma morphological characters between them are shown in Table 1.

Among these species with singly axillary gemmae, P. inflexa and P. filum are most similar to P. tibetana in the features of plants (somewhat slender) and gemmae (subglobose). In P. inflexa, the gemmae are big (>500 μm long) and leaf primordia are conspicuous, pale to green, erect or somewhat incurved, while the gemmae are small (<300μm long) and leaf primordia are inconspicuous, the same color as the body and incurved in the new species. P. tibetana differs from P. filum by its yellowish brown or deep cherry-red, <300μm long (vs. orange or black and >300 μm long) gemmae and arising at apex as well as below, the same color as the body, incurved (vs. arising only in the apex, green to pale, erect) leaf primordia.

The gemmae of P. tibetana are rather like those of P. andrewsii from Arctic regions (Shaw 1981b, 2015; Liu et al. 2018). Nevertheless, P. andrewsii is distinguished from the new species by its glossy leaves and densely clustered gemmae.

The propaguliferous species of Pohlia occurring in Tibet are very alike in habit and generally grow together, forming dense or lax turfs on soil. P. tibetana grows on loose soil mixed with two species of Pohlia having clustered axillary gemmae: P. flexuosa and P. hisae. The gametophyte features of P. tibetana, such as slender plants and spreading leaves which are somewhat contorted when dry, are very similar to P. flexuosa. The two species are confused with each other in the absence of gemmae. However, P. flexuosa is distinguished from P. tibetana by its dimorphic gemmae in dense clusters (Shaw and Torne 2009; Liu et al. 2018).

Suárez and Schiavone have conducted systematic research on the genus Pohlia in Latin America and published a series of achievements (Suárez and Schiavone 2010, 2011a, 2011b). In the revision of the propaguliferous Pohlia species (Suárez and Schiavone 2011a), the morphological characters of P. papillosa (Müll. Hal. ex A. Jaeger) Broth., such as loosely arranged leaves on the sterile plants in watery habitats, oblong or obconical gemmae in leaf axils orange or reddish with leaf primordia and body of the same color, are consistent with those of P. tibetana. In the former species, the gemmae are numerous in each axil and variable from linear-vermicular to obconical, leaf primordia erect, whereas in P. tibetana the gemmae are singly in each axil and stable rosebud shaped, and leaf primordia are inconspicuous with incurved apices.

The biodiversity of bryophytes in Tibet, China is very abundant. Eighteen species of Pohlia distributed in Tibet were recorded in Flora Bryophytorum Sinicorum (Li 2006). Liu et al. reported that P. drummondii was also distributed in Tibet in their study of propaguliferous in China (Liu et al. 2018). Wang et al. (2020) reported a new recorded species of this genus with axillary gemmae: P. tundra in Tibet. To date there are 20 species of Pohlia distributed in Tibet including 8 species with axillary gemmae.

Key to the Pohlia species with axillary gemmae in Tibet, China

1 Gemmae 1 per leaf axils 2
Gemmae numerous per leaf axils 3
2 Plants medium-size, dark green, gemmae oblong to cylindrical, dark red-brown, 350–1000 μm long, leaf primordia conspicuous, stiffly lanceolate laminate, scattered at the apex and below, green, erect P. drummondii
Plants slender, light green, gemmae spherical, yellowish brown to deep cherry-red, 200–280 μm long, leaf primordia inconspicuous, broadly somewhat triangular-laminate, at apex as well as below, the same color as the body, incurved P. tibetana
3 Plants with two different types gemmae: ellipsoidal and thread-like P. flexuosa
Plants with only one type gemmae 4
4 Gemmae spheroidal, leaf primordia inconspicuous P. camptotrachela
Gemmae obconic to filiform or cylindrical, leaf primordia conspicuous 5
5 Leaf primordia laminate, clustered at apes and also scattered along the gemma body P. tundrae
Leaf primordia peg-like or rarely laminate, restricted to apex 6
6 Gemmae obconic, leaf primordia approximately one to two times as long as the length of the gemma body P. hisae
Gemmae oblong to filiform, leaf primordia shorter than the length of the gemma body 7
7 Plants dull when dry, gemmae shape is variable on a single plant, oblong or obconic, clavate to vermicular P. annotina
Plants glossy when dry, gemmae shape is uniform on a single plant, long filiform P. leucostoma


We thank the curators and staff of HIMC, KUN, PE and XJU for specimen loaning. Thanks are also extended to Dr. Wei Li from the Institute of Applied Ecology, Chinese Academy of Sciences, Dr. Heping Ma from Tibet Agricultural and Animal Husbandry University, Xiaotong Song and Liwei Wang from China Agricultural University for their participation in field specimen collection. We are grateful to Ms. Tatyana Shubina and Mr. Guillermo Suárez for constructive comments and suggestions on the manuscript. This work was funded by the National Natural Science Foundation of China (41771054), Key Laboratory of Tibetan plateau forest ecology, Ministry of Education (XZA-JYBSYS-2021-02), the Initial Scientific Research Foundation for Doctoral Teachers of Shijiazhuang University (20BS027), the Flexible talent support project of Tibet Agricultural and Animal Husbandry University (604419044).


  • Cao N, Zhao JC (2009) Gemma morphology of family Bryaceae (Musci) and its taxonomic significance. Bulletin of Botanical Research 29(3): 264–269.
  • Imura S (1994) Vegetative diaspores in Japanese mosses. The Journal of the Hattori Botanical Laboratory 77: 177–232.
  • Li XJ (2006) Flora Bryophytorum Sinicorum (Vol. 4). Science Press, Beijing, 263 pp.
  • Liu YY, Wang XR, Zhao JC (2018) Propaguliferous species of Pohlia (Mielichhoferiaceae) in China, including two new records for China. Bryophyte Diversity and Evolution 40(2): 018–036.
  • Newton AE, Mishler BD (1994) The evolutionary significance of asexual reproduction in mosses. The Journal of the Hattori Botanical Laboratory 76: 127–145.
  • Shaw AJ (1981a) A taxonomic revision of the propaguliferous species of Pohlia (Musci) in North America. The Journal of the Hattori Botanical Laboratory 50: 1–81.
  • Shaw AJ (1981b) Pohlia andrewsii and P. tundrae, two new arctic-alpine propaguliferous species from North America. The Bryologist 84(1): 65–74.
  • Shaw AJ (1982) Pohlia Hedw. (Musci) in North and Central America and West Indies. Contributions from the University of Michigan Herbarium 15: 219–295.
  • Suárez GM, Schiavone MM (2011a) A taxonomic revision of the propaguliferous species of Pohlia (Bryaceae, Bryophyta) in Latin America. Lilloa 48(2): 217–249.
  • Uyar G, Ören M (2013) Three remarkable new moss records for South-West Asia from northern Turkey. Turkish Journal of Botany 37: 363–368.
  • Wang XR, Fan YJ, Zhao JC, Shao XM (2020) Pohlia tundrae A. J. Shaw (Mielichhoferiaceae, Bryophyta), a new recorded species to China. Acta Botanica Boreali-Occidentalia Sinica 40(6): 1070–1074.