Discovery of Mature Sporophytes of Grimmia ulaandamana (Grimmiaceae)

YU Wenxin, KOU Jin, FENG Chao*

Discovery of Mature Sporophytes of(Grimmiaceae)

YU Wenxin1, KOU Jin2, FENG Chao1*

(1. Key Laboratory of Grassland Resources, Ministry of Education of China; Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of Ministry of Agriculture; College of Grassland, Resources and Environment, Inner Mongolia Agricultural University,Hohhot 010011, China; 2. School of Life Sciences, Northeast Normal University, Changchun 130024, China)

The fertile plants ofJ. Muñoz, C. Feng, X.L. Bai & J. Kou were recently discovered in Inner Mongolia, China. The characteristics of mature sporophytes, as well as female and male plants were described.The capsule of sporophytes is longer than the arcuate seta,capsular surface with longitudinal wrinkle, epidermal cell wall of central capsule was thick,ring cells square or short rectangular, the opercle with beak. The peristome teeth had papillose and bifurcated at upper part, separated at base, the base of peristome teeth is lower than mouth of capsule. There is a layer of small cells between epidermal cells and peristome teeth, the trabeculae of capsular bones are strongly protruding about 1/3 of the base. Capsular cap base intact. The innermost female bracts are larger the leaves at stem.had important morphological variation, the fertile plants could provide more evidence to distinguish from the most similar species. The novel description and illustrations of sporophytes were presented, and the phylogenetic significance of sporophytes was discussed.

Grimmiaceae; Morphological character; Taxonomy;Inner Mongolia; China

J. Muñoz, C. Feng, X.L. Bai & J. Kou was recently described from several localities in China[1]. The species is mainly characterized by having 2-4(5)-stratose, v-shaped lamina, semi- terete to terete costa consisting of almost homogeneous cells and with four guide cells at mid-leaf, and a long plication in lower part on one or both sides of the leaf. Even though.was described based on several specimens in different herbaria, sporophytes are very rarely produced, only one sporophyte attached to the plant was available, and it was old and in such a poorcondition. Another complete capsule was found among the debris of one specimen, but without connection to the gametophytes and without seta[1]. Obviously, it is not adequate for description.

During the field trip in Saihanwula National Nature Reserve and adjacent areas in 2013, the second author made a large collection of bryophytes and more than 500 specimens were collected. In the process of identification several fertile populations of.were discovered. The characteristics of the mature sporophytes of., as well as both female plants and male plants are described here.

1 Material and methods

The specimen was studied with the anatomical and morphological methods applied for the mosses[2]. Specimen collected is deposited at BAU. Microscopic examinations and measurements were taken with a ZEISS Primo Star light microscope, while microphoto- graphs were obtained with a Canon EOS 70D camera mounted on this microscope. Specimens were examined in 2% KOH.

2 Results

J. Muñoz, C. Feng, X.L. Bai & J. Kou.(Figs. 1–3)

Type: CHINA: Inner Mongolia, Ulaan dam- Shipeng Ditch National Nature Reserve, Wanghuolou Mountain, 44°26ʹ519ʺ N, 118°45ʹ955ʺ E, on rocks, mixed with, 1 967 m, 12 July 2011, Chao Feng 2011527-2. Holotype: HIMC (seen); isotype: MA-Musci 40053.

Plants dioicous. Female plantsin dark green, loose, not hoary, readily disintegrating tufts; stem central strand consistently present; leaves spreading when moist; innermost perichaetial leaves enlarged, about 1.5 times longer than cauline leaves, 3.1–3.5 mm long, oblong-lanceolate to long-lanceolate with a hair- point, longitudinally plicate in lower half, sheathing, with a percurrent costa, with areolation of rectangular cells with moderately thickened walls, straight. Male plants similar to but differs from female plants in less robust plants and stem central strand weak or absent, irregular development in the same stem; perigonia gemmiform; innermost perigonial leaves smaller than cauline leaves, broadly ovate, concave, broadly acute, muticous, with a thin-walled areolation and a percur- rent costa. Sterile plants similar to female plants. Setae usually 2 per perichaetium, 1.3–1.8 mm long, yellowish to brown when mature, arcuate, cells rectangular, thick-walled, in cross-section with 1(–2) layers of thick-walled, strongly bulging cortical cells and a group of thin-walled medullar cells surrounding a differentiated central strand. Vaginula 0.88–1 mm long, made up of nearly rectangular cells with curved, thin, smooth walls, not tortion, in cross-section with 4–5 layers of thin to slightly thick-walled, ovate, concen- tric cells. Capsules exserted, pendent, obloid, 0.78– 1.18 mm×0.33–0.45 mm, striate,dull, dark yellow, in cross-section exterior wall slightly bulging, thick- walled. Annulus conspicuous, deciduous, made up of 2 rows of pellucid, thick-walled cells, rectangular in upper row, quadrate to short-rectangular in lower row (elongata-type). Operculum convex, with a short, straight beak, base uneven, formed by nearly isodiametric cells. Exothecial cells irregular in shape, from qua- drate to short rectangular or hexagonal, thick-walled, 20–32.5m×(7.5–)12.5–20m. Stomata present in the base of the capsule. Peristome teeth lanceolate, 0.15– 0.2 mm long, perforated in upper half, at dehiscence joined at base, trabeculae broader in lower part, dorsal lower plates smooth, upper half of dorsal side and ventral side densely covered with coarse papillae, in longitudinal section, teeth inserted below orifice, 1 layer of small cells between exothecium and teeth present, trabeculae close together, in lower third markedly protruding, in upper part scarcely protruding. Spores 9–17m diameter, spherical, finely granulose. Calyptra cucullate, smooth, in cross-section composed of 3–4 layers of thick-walled cells in the middle part.

Specimen examined: CHINA: Inner Mongolia: Saihanwula National Nature Reserve, Hexinqu: 44° 25.142′ N, 118°64.793′ E, on rock, ca 1 523 m, 10 July 2013, Li Feng 2013018, Li Feng 2013056, Li Feng 2013060, Li Feng 2013078 (NMAC).

Distribution and habitat:is only known from several districts in China: Hei- longjiang, Inner Mongolia, Hebei, Shaanxi and Yunnan, currently considered endemic to China. These plants were found on rocks, as ever, mixed withDozy & Molk. Female plants bearing mature sporophytes and male plants grew close together.

Fig. 1 Gametophyte and sporophyte of Grimmia ulaandamana. A: Plants; B: Plants when dry, female above, male below; C: Plants when moist; D: Sporophytes (left), innermost perichaetial leaf (middle) and cauline leaf (right); E: Hair-points of innermost perichaetial leaf; F: Mid-leaf cells of innermost perichaetial leaf; G: Basal part of innermost perichaetial leaf; H: Capsule when dry; I: Perigonium. J, K: Cross-sections of the same stem (male plant). L: Innermost perigonial leaves. M-O: Cross-sections of leaves. (from Li Feng 2013018, NMAC).

Fig. 2 Sporophyte of Grimmia ulaandamana. A:Calyptra; B:Middle part of calyptra; C:Cross-sections of calyptra (middle part); D:Basal part of calyptra; E:Operculum; F:Cross-section of operculum; G: Basal cells of operculum; H-J: Peristome teeth;K, L: Annulus. (fromLi Feng 2013018, NMAC).

Fig. 3 Sporophyte ofGrimmia ulaandamana. A: Exothecial cells of capsule (middle portion); B: Stomata; C: Cross-sections of urn (middle part); D: Spores; E: Exothecial cells of seta; F: Cross-section of seta; G: Exothecial cells of vaginula; H: Cross-section of vaginula. (from Li Feng 2013018, NMAC).

3 Discussion

3.1 Variation

The presence or absence of stem central strand is usually treated as a diagnostical character in the mosses taxonomy, although there are exceptions in limited genera or species[2]. In the protologue, the stem central strand was described as present in[1]. However, the strand development is correlated with sexual maturity in the light of the present observation. In addition to, we also found that stems ofP. Beauv. andin this area are characterized by stem central strand irregular developement in the same stem. This case was also noted by Maier and the same situation may occurred in other species of, such asMiel. ex Hornsch[3]. Although the presence or absence of the stem central strand is usually variable in some species of, this should not be neglected because it is rather constant and of taxonomic importance in other species[4]. For example, the stem central strand ofis usually absent, and is diagnostically useful to recognize this species in most situations, especially when the leaf shape and laminal stratification ofare usually highly variable.

The upper laminal stratification ofis usually variable from bistratose with unistratose patches to 4(5)-stratose. In, some other species such as,Hook.,(Hedw.) Lindb.,Hook. can possess the capacity to have a variable laminal stratification. The multistratose condition may occur when these plants grow in proper amount of moisture environment[5]. However, like stem central strand, the laminal stratification is rather constant and of taxo- nomic importance in other species[4].

Four guide cells at mid-leaf and two to four at leaf-insertion were described in[1]. In the present study, the costa at leaf-insertion is usually narrow with two or four guide cells, but may be occasionally wider, consisting of two or four guide cells and a double layer of companion cells (smaller than guide cells and with more thickened walls) in the ventral side of costa. This case may occur in other species ofsuch asandfrom our observation. As a consequence, examination of the costal guide cells at leaf-insertion should be more careful to distinguish them from other ventral cells of costa. In addition, number of costal guide cells at leaf-insertion was advocated as critical by Maier[3]and we agree that accurately counting the number of such cells is sometimes difficult[6], partly owing to the two outer guide cells of costa at leaf-insertion usually contiguous with laminal basal cells or unsharp boundary of costa at this position. In addition, the number of guide cells within certain species is usually variable from six to eight or from four to six. Never- theless, its number may still be an important clue when differentiating similar species of. Recently, Delgadillo-Moya[7]retained the “ventral cell” ininstead of “guide cells” to distin- guish them from the guide cells of other moss group. Indeed, the words “guide cells” in other mosses groups such as Echinodiaceae, Dicranaceae or Pottiaceae refer to the thin-walled, large cells usually present at the middle position of costa or just below the differentiated ventral epidermis cells. However, the words “ventral cell” seem to be unsuitable for genusto replace “guide cells” because of the occasional presence of companion cells on the ventral surface of costa which are not large and thin- walled.

3.2 Phylogenetic implications

The discovery of mature sporophytes of.indicates that it is not the male plants of., and the comparison with the latter species on gametophyte was in Feng et al.[1]. The additional comparison mainly on sporophyte was summaried in Table 1. While the presence or absence of laminal papillose of.was differently described from different regions[3–4,8–10], both of these plants with or without papillose of.were found in the same area.also grew in the same area where.was abundant. The large size, bulging upper laminal cells, narrowly furrowed and irregularly angled costa in cross section make.easy to be distinguished.

With the discovery of mature sporophytes and according to Cao et al.[8], Muñoz[11]and Hastings et al.[4], the presence of stem central strand, sharply keeled and lanceolate to ovate-lanceolate leaves, costa projecting on abaxial side, leaf margin recurved on one or two sides, long, arcuate to cygneous seta when moist, symmetric, pendulous and ribbed capsule, stomata present at base of capsule and cucullate caly- ptra suggest the placement of.in thesubgen.Limpricht. According to Ochyra et al.[12],was split into seven genera. Among themBrid. included the species formerly treated assubg., and.therefore may belong to this genus at this point.

In the subgen.,Bruch ex Balsamo-Crivelli & De Notaris is most similar to.. Both species share similar laminal areolation, 2-4(5)-stratose lamina and the costa protruding dorsally from the lamina, undifferen- tiated cells of the costa in cross-section, arcuate seta, exserted and striate capsule. Although.could be distinguished from the female plants of.in several aspects stated in Feng et al.[1], the differences between.and male plants of.are very minimal because the latter has semi-terete to nearly terete costa, usually smooth upper laminal cells and rectangular juxtacostal cells with straight walls. The only noteworthy difference between them is present in their different leaf posture when moist. The comparison between.and.on most gametophyte characters was in Feng et al.[1], and the differences on additional gametophyte characters and sporophyte characters were summaried. The leaf posture of.when moist is patent to spreading, but.is erect to erecto-patent. About the stem central strand of female plants,.is consistently present, and.is present above and absence below. The innermost perichaetial leaves of.isenlarged, but.is not enlarged. The exothecial cells of.isthickened walls, but.is thin walls. The calyptra of.is cucullate, not lobed and eroded at base, but.is mitrate and lobed at base. The peristome teeth of.issplit in upper half, separated above the insertion, trabeculae large in lower, teeth inserted below orifice, 1 layers of small cells between exothecium and teeth, trabeculae in lower third strongly protruding, but.is deeply split, separated down to the insertion, trabe- culae small in lower, teeth inserted at orifice, 1 or 2 layers of large cells between exothecium and teeth, trabeculae in lower third scarcely protruding. The discovery of mature sporophytes indicates that.is not the male plants of., and provides additional evidences to accept this newly described species as distinct.

Another species in subgen.with which.could be confused is(Schwägr.) Bruch & Schimp. The former occasionally has 2-4 stratose laminal cells and costa weak proxy- mally, projecting on abaxial side. Nevertheless,.differs from.by its leaves patent when moist, upper and median laminal cells with strongly thickened and moderately sinuose walls, peristome teeth inserted near orifice and mitrate calyptra.

We are grateful to Dr Jesús Muñoz, Real Jardín Botánico, for providing important literature. We thank Li Feng to collect the specimens.

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[2] ZANDER R H. Genera of the Pottiaceae: mosses of the harsh environments [J]. Bull Buffalo Soc Nat Sci, 1993, 32: 1–378.

[3] MAIER E. The genusHedw. (Grimmiaceae, Bryophyta): A morphological-anatomical study [J]. Boissiera, 2010, 63: 1–377.

[4] Hastings R I, Greven H C.Hedw [M]// Flora of North America north of Mexico, Vol. 27. New York: Oxford University Press, 2007: 225–258.

[5] DEGUCHI H. A revision of the genera,and(Musci) of Japan [J]. J Sci Hirosh Univ Ser B Div Bot, 1978, 16(2): 121–256.

[6] MILLER N G, HASTINGS R I. Taxonomy and distribution of(Bryophyta) in mountain regions of the northeastern United States [J].Bryologist, 2013, 116(1): 28–33. doi: 10.1639/0007-2745-116.1.028.

[7] Delgadillo-Moya C.(Grimmiaceae, Bryophyta) in the Neotropics [M]. México: Univ Nac Autón Méx, 2015: 8–81.

[8] CAO T, HE S, VITT D H. Grimmiaceae [M]// GAO C, CROSBY M R, HE S. Moss Flora of China, Vol. 3. Beijing: Science Press & St. Louis: Missouri Botanical Garden Press, 2003: 3–76.

[9] IGNATOVA E A, MUñOZ J. The genus(Grimmiaceae, Musci) in Russia [J]. Arctoa, 2005, 13(1): 101–182. Doi: 10.15298/ arctoa.13.13.

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乌兰坝紫萼藓(紫萼藓科)成熟孢子体的发现

于雯馨1, 寇瑾2, 冯超1*

(1. 内蒙古农业大学草原资源与环境学院，草地资源教育部重点实验室，农业部饲草栽培、加工与高效利用重点实验室，呼和浩特 010011；2. 东北师范大学生命科学学院分子表观遗传学教育部重点实验室，长春 130024)

最近在中国内蒙古发现了乌兰坝紫萼藓(J. Muñoz, C. Feng, X.L. Bai & J. Kou)的可育植株，介绍了乌兰坝紫萼藓成熟孢子体、雌株和雄株的特征。孢子体的孢蒴长于蒴柄，蒴柄弯曲，蒴壶表面具纵褶，蒴壁中部表皮细胞厚壁，环带细胞方形或短长方形，蒴盖有喙；蒴齿具疣并在上部分叉，蒴齿在基部分开，蒴齿基部低于蒴壶口，蒴壁表皮细胞和蒴齿之间存在一层小型细胞，蒴齿骨小梁在基部1/3处强烈凸出；蒴帽基部完整。最内侧雌苞叶较茎叶大。乌兰坝紫萼藓具有重要的形态特征变异，可育植株与相似种直叶紫萼藓(.)易于区分。对乌兰坝紫萼藓进行了全面的描述并配显微图，探讨了孢子体对确定其系统发育位置的重要性。

紫萼藓科；形态特征；分类学；内蒙古；中国

10.11926/jtsb.4607

2022-01-11

2022-02-25

This work was supported by the Natural Science Foundation of China (Grant No. 32060051, 42001045).

YU Wenxin (Born in1999), Female, Postgraduate student, Mainly interesting in bryophytes. E-mail: yuwenxinnmg@163.com

. E-mail: hujiaof@sina.com