A Taxonomic Revision of Oligotrichum DC. in Lam. & DC. (Polytrichaceae) in the Sino-Himalaya
by Isuru Udayanga Kariyawasam Thesis submitted in the partial fulfillment for the MSc in the Biodiversity & Taxonomy of Plants September 2013 CHAPTER 05 DISCUSSION
“Discussion itself is what most matters, the fact that we can reason together easily with a blend of wit and seriousness, and always allowing room for alternating views”.
—Stephen Greenblatt, The Swerve: How the World Became Modern.
5.1 Ecology
5.1.1 Substrate and Habitat
In the Atlas of the Bryophytes of Britain and Ireland, Long (1985) described the habitat of O. hercynicum in Britain and Ireland as: ‘A calcifuge pioneer of disturbed ground in the mountains, as on shingle by streams, gravelly footpaths, eroding slopes, gullies and stony screes, sometimes in late-snow areas; occasionally on lake margins where it may be intermittently inundated”.
According to the data recorded on herbarium specimens, these particular habitat preferences also apply to the Sino-Himalayan Oligotrichum species. In addition, important additional habitats in the Sino-Himalaya include glacial moraines and melting snow beds (O. glaciale) at high elevations (3700–4690 m), and frequently on poor soils and gravel of banks of road cuttings (almost all taxa of Sino-Himalayan Oligotrichum). The genus is typically found above the timber line (in the Sino- Himalaya this is often between 3000 and 4000 metres) but also in the temperate forest zones, but always in disturbed open areas in the forest (Figures 18 & 19) as on streamsides and banks of road cuttings. Like almost all Polytrichaceae, Oligotrichum favours nutrient-poor and lime-poor acid substrates, so it is much less common in limestone areas.
Oligotrichum falcatum is mentioned as being found in aquatic habitats in arcto-alpine areas in Alaska (Long, 1985) which gives it a beautiful silvery pale colour when submerged (Steere, 1958). But there is no record found from aquatic habitats of O.
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falcatum from the Sino-Himalaya, but several species are reported from lake margins, glacial melt-water streams and river banks. For O. nepalense habitat is unknown.
5.1.2. Altitude
O. glaciale occupies the highest altitude range (ca.3800–4830 m) of any Oligotrichum species in the Sino-Himalaya, followed by O. nepalense (ca. 4600 m) and O. falcatum (3900–4460m). O. semilamellatum and O. falcifolium are found in more or less the same altitudinal range (ca, 1470–3352 and 1720–3550 m respectively), which in turn could reflect some morphological synapomorphies between the two taxa.
Grau et al (2007) argued that the reduction in the species richness of the bryoflora in lowlands of Sino-Himalaya, as represented by the studied taxa, is due to the combination of habitat loss, inadequate sampling and unfavourable climatic conditions. The altitudinal range of Oligotrichum exceeds the elevation at which species richness is highest in the Himalaya, 2500m (Grau, et al, 2007). Water availability is a less of an ecophysiological barrier for mosses in high altitudes, and being epilithic on moist soil and rocky substrates, they are not dependent on the altitudinal range of trees as substratum. Bell & Hyvönen (2012) suggested that the reduced gametophytic morphology of Oligotrichum is associated with the prevailing environmental and climatic conditions they exist under. They further stated that the morphology of Oligotrichum is usually associated with open and exposed habitats subject to high precipitation, strong winds, and low nutrient availability. Hence these
life forms show adaptations to extreme alpine conditions, where the potential for CO2 uptake is less limiting due to other environmental stresses which add barriers to photosynthetic activity and growth rate.
This is evident in the morphologies of O. glaciale and O. nepalense which grow at very high altitudes. Both have dwarf growth forms (0.5–1.0 cm) and grow in tufts. The highly dissected compactly arranged lamellae on the leaf lamina of O. nepalense (Figure 5) and strongly wavy lamellae (Figure 9) of O. glaciale may mean that the strong development of lamellae serves to accelerate the rate of photosynthesis for the growth and survival in extreme high mountain habitats Habitat-associated climatic
92 factors like reduced irradiance levels due to very frequent cloud cover may also affect the growth form of Oligotrichum (Bell & Hyvönen, 2012).
The reduced gametophytic morphology associated with the ecology and altitudinal changes under climatic extremes could offer an interesting study to interpret the phytogeography of Oligotrichum in the Sino-Himalaya. Bell & Hyvönen (2012) in their study offer the following explanation: “The association of the reduced gametophytic morphology with isolated, extreme habitats are consistent with it having arisen convergently on multiple occasions and without similarly adapted species being forced into competition with each other for the same niches. In a sense, this association could act as an engine for the generation of cryptic or partially cryptic phylogenetic diversity, which is best explored with the aid of molecular level sequence data.”
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Figure 18. Photograph of Handel-Mazzetti’s type locality of O. obtusatum in Xiangshuihe, Ma’er Shan, Yunnan, China by D.G.Long, May 2012
Figure 19. Photograph of the habitat of O. crossidioides in Gaoligong Shan, Yunnan, China (locality of Shevock 25567) by D.G. Long, August 2005
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5.2 Phytogeography
5.2.1 Sino-Himalayan Distribution
In the Sino-Himalaya the following regional totals of Oligotrichum are recorded. NW India & Pakistan, 4 species (O. obtusatum new); Nepal, 6 species (O. glaciale, O. falcatum new); NE India, 5 species (O. falcatum and O. obtusatum new); Bhutan, 1 species; Xizang, 2 species; Sichuan, 1 species (O. obtusatum, new); and Yunnan, 5 species (O. glaciale, new). The following table (Table 4) summarises the occurrence of Oligotrichum in the Sino-Himalaya.
Table 4. Occurrence of Oligotrichum in the Sino-Himalaya.
Species NW Nepal NE Bhutan Xizang Sichuan Yunnan India India O. crossidioides _ _ _ _ + _ + O. aligerum ______+ O. falcatum _ + + _ + _ _ O. nepalense _ + _ _ _ _ _ O. obtusatum + + + _ _ + + O. semilamellatum + + + + _ _ + O. falcifolium + + + _ _ _ _ O. glaciale + + + _ _ _ +
Of the eight Oligotrichum species found in the Sino-Himalaya, three show highly localised distributions, with O. nepalense restricted to the Himalaya (only in Nepal), and O. crossidioides and O. aligerum restricted to western China. The remaining five species (O. falcatum, O. falcifolium, O. glaciale, O. obtusatum and O. semilamellatum) occur more widely from the Himalaya to China, though each has its own special distribution pattern. However, the rarity of records from Bhutan and Assam is probably due to lack of collection rather than genuine rarity, so these distributions cannot be interpreted as genuine disjunctions. Furthermore, until the present study, O. glaciale was considered an endemic to NW India, but know it is known to occur from Pakistan to China. The conclusion is therefore that all distributions of Oligotrichum in the Sino-Himalaya must be considered as provisional,
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and it is likely that further field work will show that some species are more widespread. Hence any biogeographical conclusions are very tentative.
5.2.2 Worldwide Distribution
The following table (Table 5) summarises the world-wide distribution of Sino- Himalayan Oligotrichum species
Table 5. Worldwide distribution of regional Oligotrichum species.
Species North Central South Africa Europe Asia Australia America America America O. crossidioides _ _ _ _ _ + _ O. aligerum _ + _ _ _ + _ O. falcatum + _ _ _ _ + _ O. nepalense _ _ _ _ _ + _ O. obtusatum _ _ _ _ _ + _ O. semilamellatum _ _ _ _ _ + _ O. falcifolium _ _ _ _ _ + _ O. glaciale _ _ _ _ _ + _
In contrast to the very limited conclusions possible within the Sino-Himalaya, the global distribution patterns are clearer. Six of the species are restricted to the Sino- Himalaya (O. crossidioides, O. falcifolium, O. glaciale, O. nepalense, O. obtusatum and O. semilamellatum) and the other two (O. aligerum and O. falcatum) extend beyond the Sino-Himalaya. O. aligerum appears to be a circum-Pacific taxon occurring from Central Amertica through North America, Japan, China, Korea and the Philippines. O. falcatum is an Arctic species found in Arctic America and Greenland, disjunct in the Sino-Himalaya. None of the eight species occurs in the southern hemisphere or Africa.
Table 5 therefore suggests strongly that the Sino-Himalayan is the global centre of diversity of the genus Oligotrichum.
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CONCLUSIONS
This study provides the first full taxonomic account of Oligotrichum DC. in Lam. & DC. from the Sino-Himalaya, confirming eight Oligotrichum species from the region. Three new national and regional records of O. glaciale (from Nepal, Pakistan and China: Yunnan) are reported along with two new records of O. falcatum (from India and Nepal) and two new records of O. obtusatum (from India and China: Sichuan).
The identity of the puzzling “Oligotrichum-like” specimen collected by Terry Hedderson from Pakistan is resolved by confirming it as O. glaciale C.C.Towns. The sporophytes of O. glaciale were discovered in this study from a collection of D.G. Long (Long, 22696, E) from Sikkim, India. Similarities of the morphologies between O. glaciale and the closely related taxon (based on the molecular phylogenetic study done by Bell & Hyvönen, 2012), the African Oligotrichum cavallii (Negri) G.L.Sm. is addressed. Further molecular study is needed to solve the precise taxonomic status of O. glaciale which may prove to belong to an undescribed genus of the family Polytrichaceae.
The taxonomic difficulties presented by Oligotrichum specimens has led to many misidentifications some of the widely distributed species, which are morpholgically rather variable, particularly O.semilamellatum (Hook.f.) Mitt. and O.falcifolium (Griff.) G.L.Sm. These difficulties have been resolved and many of the misidentifications made by the collectors of 19th century are re-determined. Oligotrichum aristatulum Broth., Oligotrichum semilamellatum var. darjeelingense Gangulee and Oligotrichum semilamellatum var. edentatum Gangulee. are newely synonymised with Oligotrichum semilamellatum (Hook.f.) Mitt.
Further taxonomic work is needed towards a full world monograph of Oligotrichum to assess the many published names and their synonymy as well as to address the herbarium names where their identity requires clarification. However, the present study has dealt with the region of the world with greatest species diversity in the genus and extending this to the rest of the world would be relatively straightforward.
The genus Oligotrichum offers interesting research avenues in phytogeography and molecular biology, though the supporting taxonomic work should be completed first.
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This revision was unable to describe the peristome characters adequately for the species due to absence and lack of perfect sporophyte material. Collectors should note a need for more sporophyte material from all Oligotrichum collections from the Sino- Himalaya.
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References
** Only some of the whole references of the protologues are mentioned here. All protologues are cited under each species descriptions in Chapter 03 (Taxonomic Revision).
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ABSTRACT
A taxonomic revision of Sino-Himalayan Oligotrichum DC. is provided. Recent regional fieldwork has resulted in new collections of Oligotrichum previously unstudied. Many older specimens were misidentified and required revision. Light microscopy (LM) and Scanning Electron Microscopy (SEM) were used to explore taxonomic characters significant for species delimitation. Eight species are confirmed from the study-area: O. crossidioides P.-C. Chen & T.L. Wan ex W.X. Xu & R.L. Xiong, O. aligerum Mitt, O. falcatum Steere., O. nepalense G.L. Sm., O. obtusatum Broth., O. semilamellatum (Hook.f.) Mitt., O. falcifolium (Griff.) G.L.Sm. and O. glaciale C.C.Towns. O. hercynicum (Hedw.) Lam & DC. is excluded from the region. New observations are reported on some important characters particularly leaf lamellae and sporophytes to resolve some taxonomic problems.
Keys, descriptions and illustrations are provided to species, as well as relevant synonymy, typification, ecological notes and geographical distribution. Seven new records are reported: Nepal and India (O. falcatum), India and China, Sichuan (O. obtusatum) and Pakistan, Nepal and China (O. glaciale).
The sporophytes of O. glaciale are reported for the first time and described and illustrated. O. aristatulum Broth., O. semilamellatum var. darjeelingense Gangulee and var. edentatum Gangulee. are newly synonymised with O. semilamellatum (Hook.f.) Mitt. Taxonomic notes, particularly differences between O. semilamellatum and O. falcifolium and the affinities between O.glaciale and the African O. cavallii (Negri) G.L.Sm are presented. Finally, some observations on ecology and phytogeography of the species are given.
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ACKNOWLEDGEMENTS
I am very much indebted to David G. Long, my principal supervisor for his excellent supervision, unstinting and friendly support throughout the course of this project, always offering his expertise enthusiastically and ungrudgingly. His comments, suggestions, and explanations expanded my horizon on" Bryology" to become a "Budding Bryologist". A big thank-you to my subsidiary supervisor, Neil Bell, University of Helsinki for his outstanding supervision, guidance, encouragement and never-ending support extended to me throughout the course of this project. His advice (through countless emails and facebook messages) has shaped almost every aspect of the study, including its initial conceptualisation based on his molecular work. Special thanks goes to David Bell, bryologist, who helped me in numerous ways giving valuable advice on many aspects of bryology.
I am indebted to Mark Hughes, my tutor, who helped me in numerous ways throughout the MSc course and particularly helped me a lot in producing geographic maps to portray the species distributions. Heart-felt thanks are extended to Frieda Christie for her assistance and invaluable training in electron microscopy, and LM imaging. In particular, I would also like to thank Louise Olley for her valuable advices concerning my camera Lucida illustrations. Many thanks to Adele Smith for handling all the herbarium loans without any delay. I extend my thanks to David Middleton for his valuable support in solving the nomenclatural problems of species. Special thanks goes to my colleague Simon Tan and Dennis Ma from Kunming Institute of Botany who helped me to translate Chinese herbarium labels.
It is my obligation to thank all residents of the Cryptogamic workroom, whom made it a "wonderful place" to work, always with their smiling faces, encouragement and good advice. I would also thank everyone at RBGE for making me feel very welcome from the beginning of the MSc course. I am very much indebted to Louis Ronse de Craene, the MSc project coordinator who helped me in numerous ways throughout the whole MSc project.
My participation in this course was made possible by the financial assistance received from the Commonwealth Association, UK, to whom I am very much indebted. I
2 extend my thanks to the international herbaria who loaned me their precious herbarium material to facilitate this project without delay.
Last but not least, I would like to thank all my fellow MSc students for their friendship which has created a wonderful international blend among us over the past year. I wish them all the very best for all their future endeavours.
Finally a big thank-you goes to my parents. Without their encouragement, I would not have been here and would have missed out this wonderful opportunity. They are always behind me as my shadow, guiding me in every aspect in my life to sail for new horizons.
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CONTENTS
ABSTRACT...... 1
ACKNOWLEDGEMENTS...... 2
1. INTRODUCTION...... 8
1.1 Aims of the study...... 9
1.2 Background information on the Sino-Himalaya...... 8
1.3 A brief taxonomic history of Oligotrichum in the Sino-Himalaya...... 10
1.4 Some key morphological characters used to identify the species of Oligotrichum and distinguish these from other related taxa of Polytrichaceae...... 15
1.5 Recent molecular taxonomic studies on Oligotrichum...... 25
1.6 Phylogenetic relationship of Oligotrichum with closely related taxa...... 26
2. MATERIALS AND METHODS...... 29
2.1 Material...... 29
2.2 Light Microscopy (LM)...... 29
2.2.1 Observations and measurements...... 29
2.2.2 Images...... 30 2.3 Scanning Electron Microscopy (SEM)...... 30
2.4 Mapping ...... 30
3. TAXONOMIC REVISION...... 31
3.1 Oligotrichum Cand. in Lam. & Cand...... 31
3.2 Key to species of Oligotrichum in the Sino-Himalaya...... 32
3.2.1 Oligotrichum crossidioides P.C. Chen & T.L.Wang ex W. X. Xu & R.L. Xiong...... 34
3.2.2 Oligotrichum aligerum Mitt...... 38
3.2.3 Oligotrichum falcatum Steere...... 41
3.2.4 Oligotrichum nepalense G.L.Sm...... 45
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3.2.5 Oligotrichum obtusatum Broth...... 48
3.2.6 Oligotrichum semilamellatum (Hook. F.) Mitt...... 52
3.2.7 Oligotrichum falcifolium (Griff) G.L.Sm...... 58
3.2.8 Oligotrichum glaciale C.C.Towns...... 62
3.2.9 Doubtful and excluded taxa from the region...... 66
3.2.9.1 Oligotrichum hercynicum (Hedw.) Lam.& DC...... 66
3.2.9.2 Oligotrichum lineatum G.L.Sm...... 65
3.2.9. 3. Oligotrichum semilamellatum var. yuennanense Broth. ex P.-C. Chen...... 66
3.2.9.4. Oligotrichum armatum Broth...... 66
3.2.9.5.Oligotrichum serratomarginatum Lou & Wu ...... 67
4. OBSERVATIONS BASED ON MORPHOLOGY AND TAXONOMIC CHARACTERS...... 68
4.1 Gametophytic Characters...... 68
4.1.1 Plant habit...... 68
4.1.2 Stem leaves...... 69
4.1.3 Leaf lamellae...... 70
4.1.4 Leaf cells ...... 75
4.2 Sporophytic Characters...... 76
5. DISCUSSION...... 91
5.1 Ecology...... 91
5.1.1 Substrate and habitat...... 91
5.1.2 Altitude...... 92
5.2 Phytogeography...... 95
5.2.1 Sino-Himalayan distribution...... 95
5.2.2 Worldwide distribution...... 96
6. CONCLUSIONS...... 97
7. REFERENCES...... 99
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LIST OF MAPS, FIGURES AND TABLES.
LIST OF MAPS
1. Map of the study area...... 9
2. Distribution of Oligotrichum crossidioides in the Sino-Himalaya...... 36
3. Distribution of Oligotrichum aligerum in the Sino-Himalaya...... 39
4. Distribution of Oligotrichum falcatum in the Sino-Himalaya...... 43
5. Distribution of Oligotrichum nepalense in the Sino-Himalaya...... 46
6. Distribution of Oligotrichum obtusatum in the Sino-Himalaya...... 50
7. Distribution of Oligotrichum semilamellatum in the Sino-Himalaya...... 56
8. Distribution of Oligotrichum falcifolium in the Sino-Himalaya...... 60
9. Distribution of Oligotrichum glaciale in the Sino-Himalaya...... 64
LIST OF FIGURES
1. Photographs of living Oligotrichum plants...... 14
2.Oligotrichum crossidioides...... 37
3. Oligotrichum aligerum...... 40
4. Oligotrichum falcatum...... 44
5. Oligotrichum nepalense...... 47
6. Oligotrichum obtusatum...... 51
7. Oligotrichum semilamellatum...... 57
8. Oligotrichum falcifolium...... 61
9. Oligotrichum glaciale...... 65
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10. SEM images of highly dissected adaxial leaf lamellae on the leaf costa of Oligotrichum nepalense...... 72
11. SEM images of leaf lamellae on the abaxial surface of Oligotrichum crossidioides...... 73
12. Cross-sections of Oligotrichum species showing the distribution of abaxial and adaxial lamellae...... 74
13. Capsule and spore morphologies of O. semilamellatum and O.falcifolium ...... 78
14. Cryptopore and phaneropore stomata at the base of Oligotrichum capsules...... 80
15. SEM images of the sporophyte of Oligotrichum glaciale...... 81
16. SEM images of stomata in Oligotrichum...... 82
17.SEM image of the peristome of O. obtusatum showing single, narrow, pointed and well separated peristome teeth...... 83
18. Photograph of Handel-Mazzetti's type locality of O.obtusatum in Xiangshuihe, Ma'er Shan, Yunnan, China...... 94
19.Photograph of the habitat of O.crossidioides in Gaoligong Shan, Yunnan, China...... 94
LIST OF TABLES
1.Key morphological characters used tom separate the Sino-Himalayan Oligotrichum species in literature...... 19
2. Sporophyte characters of O.semilamellatum and O. falcifolium ...... 77
3. Morphological characters used to separate the Sino-Himalayan Oligotrichum species using new observations...... 85
4. Occurrence of Oligotrichum in the Sino-Himalaya...... 95
5. Worldwide distribution of the regional Oligotrichum species...... 96
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CHAPTER 01
INTRODUCTION
“A thinker sees his own actions as experiments and questions as attempts to find out something. Success and failure are for him answers above all.” ― Friedrich Nietzsche.
1.1 Aims of the Study.
Oligotrichum DC. in Lam. & DC. (Polytrichaceae Hedw.) is a genus of about 28 recognised species and some very poorly-known species (Bell & Hyvönen, 2010). With ten species reported from the region in various sources of taxonomic literature , the Sino-Himalaya is a strong candidate to be considered as the centre of diversity of the genus. The genus has never been monographed (Ivanova et al., 2005), and no proper regional taxonomic revision exists for the species. Bell & Hyvönen (2012) have inferred a robust backbone phylogeny, excluding most of the southern hemisphere species from the genus. Many of the Oligotrichum species in the Northern Hemisphere were misidentified by scientists in the 19th century and the some of the current species concepts of the region are still unclear. Moreover, recent field work during last twenty five years in the Himalaya and western China by D.G.Long has resulted in collections of about 65 unidentified specimens of Oligotrichum housed in the Herbarium of Royal Botanic Garden, Edinburgh (E) which also required a taxonomic revision. Hence the purpose of the study is to revise the genus Oligotrichum and to investigate the ecology and phytogeography of it in the Sino-Himalaya.
Aims of the present study include; To revise the genus Oligotrichum in the Sino-Himalaya. To investigate key taxonomic characters to distinguish species through Light Microscopy (LM) and Scanning Electron Microscopy (SEM). To explore the confusion between Oligotrichum semilamellatum (Hook.f.) Mitt. and Oligotrichum falcifolium (Griff.) G.L.Sm. To study and investigate the taxonomic status of the “puzzling specimen” from Pakistan collected by T.A.J. Hedderson which shows similarities to the East African Oligotrichum cavallii (G. Negri) G.L.Sm.
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To investigate the ecology and the phytogeography of Oligotrichum species in Sino-Himalaya.
1.2 Background Information on the Sino-Himalaya. The Sino-Himalayan region (Map 1) includes the whole mountain chain of the Himalayas from north-west Inda, 3000 km east to North Burma (Mani, 1994), and continues further east linking with the Hengduan mountains of Yunnan and Sichuan in Western China (Schill & Long, 2003). The geographic range includes the north- western and north-eastern Indian districts (Jammu and Kashmir, Himachal Pradesh and Uttaranchal (now Uttarakhand), West Bengal, Sikkim, Darjeeling, Assam and Arunachal Pradesh), Nepal, Bhutan and provinces of south-western China (Yunnan, Sichuan and Xizang (Tibet)). (Dalton & Long, 2013, Vana & Long, 2009). Overall, the Sino-Himalaya spans the area from approximately 24° to 32°N and 70° to 105º E (Wilbraham & Long, 2005).
Map 1. Map of the study area; shaded geographic regions are encompassed in the Sino-Himalaya.
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The Sino-Himalaya is a relatively young (Schill & Long, 2003), linear mountain range, which forms an effective, natural phytogeographical unit (Wilbraham & Long, 2005, Dalton et al 2013). The region has a Tertiary orogeny, then was modified by Pleistocene glaciations and subsequent post-Pleistocene mountain uplifts (Mani, 1994). During the Mesozoic, the Hengduan Mountains were formed and have been modified by continental movement during the Cenozoic (Chaplin, 2005; Ward, 1927). The Chinese name “Hengduan” means the “Transverse” mountains, which describes the north-south orientation in contrary to the linear, east-west distribution of the Himalayas (Chaplin, 2005).
Even though the Himalayan and Hengduan mountains are of different geological ages, the flora of two mountain ranges are naturally related due to their close proximity and almost continuous range (Ward, 1927, Grau et al., 2007,Wu, 2000). The general climatic conditions in the east are semi-oceanic, becoming increasingly continental westwards (Schill & Long, 2003). The flora can be categorised broadly into lowland forest ecosystems and the high altitude communities above 3000 m (Mani, 1994). The altitudinal gradient and the dynamic fluctuations of the climatic conditions combine to give a wide array of climatic and vegetation zones including montane-temperate, subtropical and subalpine forest and associated grassland and scrub which leads to a huge diversity of flora including bryophytes (Grau et al., 2007).
1.3 A Brief Taxonomic History of Oligotrichum in the Sino-Himalaya.
From the beginning of the 19th century, after description of the type genus of Polytrichaceae, Polytrichum, by Hedwig, there was a rapid increase in discovery and description of new members of Polytrichaceae by different scientists around the world. The genus Oligotrichum DC. in Lam. & DC. was first described by Lamarck and de Candolle in 1805. They used the character "calyptra simplex subglabra" (which means the calyptra has a few hairs), to characterise the genus Oligotrichum.
In the genus description they enumerated the key characters which differentiate Oligotrichum from related genera, [translation] "the Oligotrichs are dioecious and have their male flowers in terminal discs; the head-dress (i.e. calyptra) is bristling with a few projections”; Hedwig states that, like those of “Polytrichs”, the nectaries
10 are welded to the cap, but are significantly different in that they are attached by the base, not the top. He further states that, [translation] “this genus is an intermediate between Polytrichs, which has the peristome, and Orthotrichs, which has the cap. The Oligotrichs have corrugated leaves, with almost membranous consistency." The type (and only) species described by them was Oligotrichum hercynicum. They synonymised under O. hercynicum two earlier species described before the nomenclatural starting-point of 1801 (and therefore illegitimate) as Polytrichum hercynicum Hedw. and Orthotrichum hercynicum Hoffm.
In 1864, Oligotrichum aligerum Mitt. was described by William Mitten (1896-1906) from specimens collected from the Canadian Rocky Mountains by Thomas Drummond. There he described and illustrated the species as "In size and general appearance like O. hercynicum, for which species it was overlooked by Drummond himself; but its leaves are narrower, and when dry more crisped, and the presence of the lamellae on the underside of the leaf itself, as well as upon both sides of the nerve, is remarkable and peculiar". In the early 1980s several Chinese collectors collected O. aligerum and some allied taxa from the Yunnan Province of China and O. aligerum was reported from Japan, Korea, Taiwan and the Philippines (Noguchi, 1987); in North and Central America the species is well-distributed (Smith, 2007).
In 1859, Oligotrichum semilamellatum (Hook.f.) Mitt., was described by J.D.Hooker (1837) as Polytrichum semilamellatum based on material collected by John Forbes Royle (1798-1858) from the NW Himalaya of India (Long, 1995). Royle's herbarium, including his bryophyte collection, is preserved in Liverpool (LIV), and some duplicates also in Hooker's herbarium in BM (Long, 1995). William Hooker applied the herbarium name Polytrichum lamellatum to the LIV specimen but the species epithet was changed by his son Joseph Hooker to semilamellatum. Smith (1976) cited "types" from NY and BM; and he annotated BM specimen as the "holotype" (Long, 1995). Long isolectotypified the LIV specimen in 1995.
At the beginning of 20th century many British collectors visited the Sikkim Himalaya and Nepal which added many new collections of the genus Oligotrichum. These collections represent several different species, suggesting that the Sino-Himalaya is the centre of diversity the genus. V.F. Brotherus (1849-1929) described three new Oligotrichum species from the Sino-Himalayan O. obtusatum Broth., O. aristatulum
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Broth. and O. armatum Broth. Brotherus stated that O. armatum had an affinity to the species O. semilamellatum in his protologue. Smith (1971), in his conspectus of Polytrichaceae, used some figures of the O. armatum leaf lamina with adaxial lamellae to show the bistratose nature of the leaf lamina and the nature of the leaf lamellae. However, O. armatum was later synonymised and removed from the genus (as Pogonatum subfuscatum Broth.) by Wang & Luo (1994). The characteristic feature of O. aristatulum he mentioned in the protologue is that the upper leaves are entire with aristatulate leaf apices whereas O.obtusatum has obtuse leaf apices.
In 1958, Oligotrichum falcatum Steere was described by W.C. Steere (1907-1989), from Alaska. In the original description he mentioned that O. falcatum could be easily distinguished from the more widespread northern species, O. hercynicum, by its regular, falcate-secund leaves in both moist and dry conditions. This was first recorded in the region (China and Himalaya) by Wu & Wang (2005) in The Moss Flora of China. In the absence of sporophytes at the time of collection, this was transferred to Psilopilum (Crum et al., 1965). But in 1960, a few capsules were discovered by O. Mårtensson, K. Holmen and W.C. Steere in the original locality (Steere & Smith, 1975). These indicated that the original generic placement in Oligotrichum had been correct. In 1974, Z. Iwatsuki and Steere discovered a large population of O. falcatum with sporophytes, several kilometres away from the original locality and later Smith & Steere (1975) described in detail the sporophyte of O. falcatum.
In 1969, H.C. Gangulee treated Oligotrichum semilamellatum Hook.(f.) Mitt. in a broad sense (sensu lato) in his "Mosses of Eastern India and Adjacent Regions" (Fascicle 1). He introduced three varieties of O. semilamellatum based on leaf and capsule morphology and some cytological evidence. He described as new O. semilamellatum var. darjeelingense Gangulee (from his own collection), O. semilamellatum var. edentatum Gangulee (from Darjeeling-Sikkim) and O. semilamellatum var. falcifolium (Griff.) Gangulee (based on the Griffith type specimen Polytrichum falcifolium from Bogapanee, in the Khasia Hills of Assam). But, in 1969, G.L. Smith made the new combination Oligotrichum falcifolium (Griff.) G.L.Sm, with the basionym Polytrichum falcifolium Griff. Many collectors in the early 20th century such as A.C. Hartless misidentified O. falcifolium as O. semilamellatum and G.L.Smith re-determined many of the misidentifications made
12 during the early 19th century housed in NY and BM. Smith (1972) further mentioned that "O. semilamellatum has been incorrectly applied to a highly variable taxon, properly called O. falcifolium (Griff.) G.Sm., which is allied to O. aligerum Mitt."
Oligotrichum nepalense G.L.Sm was described as a new species by G.L. Smith in 1976 from Eastern Nepal. The species was described using only leaf characters, because sporophytes were unknown at the time of collection. This is a very distinctive species which has highly dissected adaxial leaf lamellae which are 10(–15) cells tall. In the original description Smith further explained that this new species is unmistakably allied to the Northern Hemisphere species, Oligotrichum falcatum Steere.
Oligotrichum crossidiodes P.-C.Chen & T.L. Wan ex W.X.Xu & R.L.Xiong was described more recently in 1984 from Yunnan Province, China and was described as a very distinctive species with lamellae on both adaxial and abaxial surfaces. Wu and Wang (2005) considered this species to be endemic to China.
The most recently-described species of Oligotrichum in the Sino-Himalaya is Oligotrichum glaciale C.C.Towns., published in 1998. This was first collected in 1989 by Clifford Townsend from Kashmir, NW India. In the original description he explained that, though the plant in the field resembled the genus Psilopilum, microscopic examination of the marginal cells of the leaves and the nature of ventral lamellae distinguished it from the arctic moss genus, Psilopilum.
There are some additional poorly-known taxa recorded from the region in some literature sources which are only ‘herbarium names’ which are not validly published (nomina nuda). Hence, one of the aims of this taxonomic revision is to establish a robust revision of all accepted taxa of the genus in the Sino Himalaya and also to clarify the status of some doubtful, poorly-known and excluded taxa from the study- area based on available literature sources and herbarium specimens.
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A
B
Figure 1. Photographs of living Oligotrichum plants by D.G. Long A, Oligotrichum hercynicum, gametophyte, Long s.n. (Cairngorm Mountains, Scotland); B, O. hercynicum, capsules, Long s.n. (Cairngorm Mountains, Scotland).
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1.4 Some Key Morphological Characters used to Identify the Species of Oligotrichum and Distinguish these from other Related Taxa of Polytrichaceae
Vegetative and capsule characters are widely used in various literature sources to delimit the taxa in the genus Oligotrichum. The most important characters are as follows:
Branching. Most Polytrichaceae plants are unbranched or only sparingly branched, or branch only by subfloral innovations from beneath the perichaetium or female inflorescences (Smith 1971, Hyvönen et al., 1998). Some species of Oligotrichum; O. falcatum (Long, 1985), O. aligerum and O. crossidioides (Wu & Wang, 2005) show branching by innovations.
Leaf characters. As in all mosses, leaf characters provide important taxonomic evidence to identify the taxa. Leaf shape, leaf margin, leaf apex, abaxial and adaxial leaf lamellae and the leaf lamina cells are the most important taxonomic characters used to separate taxa in many genera of the Polytrichaceae, including Oligotrichum.
Leaf margin. In general, leaves of Polytrichaceae have serrate leaf margins (Smith, 1971, Schofield, 1985). They may be either sharply serrate (Pogonatum,, Atrichum) or merely serrate or almost entire (Notoligotrichum, Oligotrichum) (Smith, 1971, Hyvönen et al., 1998). Serrations can be composed of a single, terminal cell or several cells (Smith (1971).
Leaf apex. Leaf apices have a narrow range of diversity in Polytrichaceae. In many Sino-Himalayan Species leaf apices are acute whereas some show obtuse apices (Table 1).
Leaf lamellae. Number, height and waviness of adaxial (ventral) and abaxial (dorsal) photosynthetic leaf lamellae are key morphological characters used to separate many of the taxa in the genus Oligotrichum in various taxonomic publications (Long, 1985, Noguchi, 1987, Wu & Wang, 2005, Smith, 2007, Hyvönen et al., 1998). The photosynthetic lamellae borne on the adaxial surface are a hallmark of members of Polytrichaceae. Some members such as Alophosia, and a few Pogonatum species lack
15 lamellae, which Smith (1971) considered to be an anomalous situation in the genus. Where lamellae are lacking it has been generally assumed that they have been lost (Hyvönen et al., 1998). Adaxial leaf lamellae of Polytrichaceae vary in shape from straight to highly wavy and in height from one series of cells to as many as 15 cells (Smith, 1971). Bell & Hyvönen (2012) hypothesised that the degree of development of leaf lamellae in different species is linked to the prevailing environmental conditions. Leaf lamellae act to increase the surface area available for CO2 uptake and allow the efficient use of sunlight for photosynthesis. When mosses grow in shaded habitats, reduction of leaf lamellae is likely to be associated with limited sunlight due to CO2 uptake no longer being photosynthetically limiting. Bell & Hyvönen (2012) further explained that "the Oligotrichum morphology is usually associated with open habitats, albeit exposed ones subject to high precipitation, strong winds, and low nutrient availability. It seems likely that these life forms represent adaptations to extreme conditions where the potential for CO2 uptake is less limiting due to other stresses imposing constraints on photosynthesis, rate of growth, or plant morphology. Reduced irradiance levels due to very frequent cloud cover may also be a factor. Such habitats tend to be isolated from each other, either on a global scale in the case of arctic and cool temperate regions of the Northern and Southern Hemispheres, or on a more local scale for individual mountains, mountain ranges, and oceanic islands. Oligotrichum s.str. is most diverse in the northern arctic and temperate regions and especially in the Himalayas and the mountainous regions of China such as Yunanan, while southern Oligotrichum species are very widely scattered in South Africa, New Zealand, Patagonia, Papua New Guinea, Tristan da Chua and in the mountain regions of Brazil and the tropical American Andes".
In some species of Polytrichaceae lamellae are confined to the costa while in others they occur on both the leaf lamina and costa (Smith, 1971, Schofield, 1985, Hyvönen et al., 1998). In Dendroligotrichum, Atrichopsis and Lyellia the lamellae-free portion of the leaf blade is bistratose (Hyvönen et al., 1998). In many Oligotrichum species this elamellate portion is unistratose (Wu & Wang, 2005, Long, 1985, Smith, 2007). In taxa with broadly lamellated leaves such as Polytrichum there is a very narrow lamellae-free portion of the lamina along the leaf margin.
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The apical cells of the adaxial leaf lamellae in Polytrichaceae may be undifferentiated or variously modified in size and/ or shape. The form of these marginal cells is important for distinguishing between species of some genera of Polytrichaceae including Pogonatum (Ivanova et al., 1998).
Calyptra. The characteristic "hair-like" outgrowths of the calyptra gave rise to the vernacular name "hair-cap mosses” for the Polytrichaceae as a whole (Schofield, 1985). The presence or absence of these hair-like structures in the calyptra has traditionally been used as a major character in the delimitation of genera. The names of many genera reflect these distinctions, such as Atrichum (no hair-like out growths of the calyptra), Oligotrichum (a few hair-like out growths) and Polytrichum (many hair-like outgrowths).
Capsule. The capsules of Polytrichaceae show a wide variation in size and shape. They can be ovoid, cylindrical, bell-shaped, radial, bilateral, or dorsiventral, with sharp or rounded angles, with low ridges or terete (Smith, 1971, Schofield, 1985). Almost all Oligotrichum species have terete capsules, whereas O. aligerum Mitt. often has four-to-five sided capsules (Smith, 1971). Exothecial cells of the capsule also show useful taxonomic characters cited by some authors (Smith 1971, Hyvönen et al., 1998). Exothecial cells have different shapes including quadrate, linear or hexagonal (Smith, 1971). The exothecial cells which surround the stomata in the capsules of some species of Polytrichaceae including Psilopilum, Oligotrichum and Polytrichadelpus bulge outward and partially cover the guard cells (Smith, 1971). In many Polytrichaceae, exothecial cells form a distinct band of small, quadrate cells, near the capsule base, associated with stomata (Smith, 1971).
Stomata. Stomata are present in the sporophytes of all genera of Polytrichaceae, except Atrichum, and Pogonatum (Smith, 1971, Hyvönen et al., 1998) Absence of stomata in Pogonatum and Atrichum is a synapomorphic character of the genus (Hyvönen, 1989). Smith (1971) reported that the numbers of stomata per capsule range from more than 200 to none. He further reported that in most taxa of Polytrichaceae, stomata are restricted to an area of the capsule neck (base), whereas in Dendroligotrichum and in some species of Oligotrichum and Polytrichadelphus, stomata are more or less scattered over the exothecium of the urn. In some genera
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stomata are superficial, forming phaneropore stomata (i.e stoma fully exposed on the surface, with its guard cells on the same level as the adjacent exothecial cells) whereas some have cryptopore stomata (i.e. stoma deeply immersed in a crypt or a depression or chamber formed by adjacent overarching exothecial cells; Smith, 1971, Schofield, 1985). Hence, the distribution and the nature of stomata in the capsule is a taxonomic character used to separate taxa by different authors.
Peristome and epiphragm. The peristome of most Polytrichaceae consists of a single ring of teeth, united to the epiphragm, i.e. a circular membrane formed by the expanded tip of the columella and attached to the ends of the peristome teeth (Malcolm & Malcolm, 2006; Smith, 1971). Polytrichaceae is the only family which has a “ nematodontous” type of peristome ( i.e composed of entire cells rather than just cell wall remnants (Schofield, 1985). The peristome teeth of Polytrichaceae members may be either single or compound. A single peristome consists of only one teeth whereas in a double peristome, the outer peristome or the “exostome” consists of teeth, and the inner peristome or the “endostome” consists of segments, sometimes alternating with cilia, and often arising from a basal membrane (Malcolm & Malcolm, 2006). Smith (1971) reported that compound peristome teeth have been observed in some species of Oligotrichum (O. parallelum (Mitt.) Kindb.), Pogonatum and Polytrichum. The number of peristome teeth can be either 32 or 64 (Schofield, 1985). Smith (1971) noted that 32 peristome teeth are the rule in species of Atrichum, Oligotrichum, Psilopilum, Pogonatum etc.
The following table (Table 1) provides a concise summary, based on literature sources, of currently accepted diagnostic morphological characters, compiled from relevant literature (Wu & Wang 2005, Smith, 2007, Long, 1985, Gangulee, 1969, Noguchi, 1987) and all the species protologues (cited in the reference list) of the Oligotrichum species in the Sino-Himalaya.
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Table 1. Key morphological characters used to separate the Sino-Himalayan Oligotrichum species in literature.
Character O. crossidioides O. aligerum O. falcatum *O. nepalense Plant height 1.0–1.5 cm 0.5–1.5 (2.0) cm 1.5–5.0 cm 1.5–1.0 cm Branching Plants in tufts, simply Simply to sparingly Simple to much branched Not mentioned branching by innovations. branched by innovations by innovations Leave orientation in Mostly erect when dry and Often crisped when dray Acute-incurved & Falcate-secunded and dry and wet conditions erect-patent when wet and erect-patent when falcate-secund when both markedly concave in both wet dry and wet. dry and wet conditions Leaf length 2.5– 3.5 mm 2.5– 3.5 mm 1.5– 2.5 mm Not mentioned Leaf width 0.2–0.4 mm 0.3–0.5 mm 0.6–1.0mm Not mentioned Leaf margin Entire Serrate or serrulate Irregularly crenulate to Remotely serrulate/ obscurely serrulate laciniate Leaf shape Lanceolate Lanceolate Lanceolate Not mentioned Leaf apex Acute/Obtuse Acute Acute Acute Sheathing at base Slightly sheathing Slightly sheathing Not clearly sheathing Not clearly sheathing Costa Broad, often reaching at Broad, often reaching at Broad, often reaching at Broad, often reaching at apex apex apex apex Ventral lamellae On both costa & lamina Restricted to costa Restricted to costa Restricted to costa 1. No. of rows 8(9)–11 6–9 8(–10)–15(–16) ~6 2. Height 4–6 5–10 4–12 10(–15) 3. Straightness Strongly wavy & papillose Linear, regularly spaced Strongly wavy Highly dissected; winged
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Dorsal lamellae In both lamina and costa In both lamina and costa Rare; sometimes near the Not mentioned 1. No. of rows 19 3–4(5) apex; or sometimes none 2. Height 1–2 1–3 Median leaf cells Not mentioned 1. Diameter 8–10 μm 10–15 μm 7–18 μm 2. Shape Quadrate Rounded to quadrate Quadrate to polygonal 3. Cell walls Thin-walled Thin-walled Thin-walled Basal cells Not mentioned 1. Length and width 20–30 ×8–10μm 25–50 ×10–15μm 18–35 ×7–18 μm 2. Shape Rectangular Rectangular Rectangular 3. Cell walls Slightly thick-walled Thin-walled Thick-walled Setae Not mentioned 1.6–2.1cm, straight; 3–4 cm, straight, 1.0–1.5 cm, straight, reddish-brown. reddish brown- yellow, reddish brown wiry/ often twisted in distal half when dry. Capsule Not mentioned 1. Shape Cylindrical, mostly curved Oblong-Ovoid with 4-5 Cylindrical, mostly sides curved 2. Lid Conic with short beak Shortly cylindraical with Conic with short beak short beak.
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3. Calyptra Cucullate, smooth with Cucullate, smooth, often Cucullate, smooth with Not mentioned several short cilia on the with short cilia on apex. several short cilia on the apex apex Peristome 32 32, single (double?), pale 32, with clear peristome Not mentioned in colour mebrane Spores Not mentioned 1. Shape Spherical Spherical Spherical 2. Diameter 12–15 μm 10–13 μm 10(–13) –19(–21) μm 3. Ornamentation Verrucose Verrucose Verrucose
* O. nepalense G.L. Sm. was only briefly described in the protologue which contains inadequate information about the taxon. At the time of describing the species no sporophytes were observed by the author. Hence, sporophytic characters are not mentioned in the literature
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Table 1. Cont.
Character O.obtusatum O.semilamellatum s.l. O. falcifolium **O. glaciale Plant height 0.5–1.2 cm 1.0–3.0 cm 0.7–1.0 cm ~ 1.0 cm Branching Unbranched Unbranched Unbranched Dense foliage with innovations Leave orientation in Incurved when dry and erect- Curled and appressed at Curled, twisted and Leaves profoundly dry and wet patent when wet. apices when dry and erect- incurved when dry and concave. Leaf orientation conditions patent when moist falcate when wet. in dry and wet conditions not mentioned in the protologue Leaf length 1.5– 2.0 mm 2.5– 4.5 mm + 2.0 mm 1.6– 2.6 mm Leaf width 0.5–1.0 mm 0.5–0.8 mm + 0.6 mm Not mentioned Leaf margin Serrate Serrate Not mentioned (Slightly) dentate Leaf shape Oblong-oval/ Oblanceolate Lanceolate Lanceolate Not mentioned Leaf apex Obtuse/ Acute Acute /acuminate Acute/ acuminate Obtuse Sheathing at base Slightly sheathing Slightly sheathing No clear sheathing No clear sheathing Costa Broad, often reaching at apex Vanishing below at apex Broad, often reaching at Broad, often reaching at apex apex Ventral lamellae Restricted to costa Restricted to costa Restricted to costa Restricted to costa 1. No. of rows 3–10 5–10 Not mentioned 7–(–8) –12 2. Height 3–5 3–6 Not mentioned 8–12 cells
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3. Straightness Slightly wavy Slightly wavy/ undulate Not mentioned Wavy Dorsal lamellae Only a very few lamellae on the A few rudimentary No lamellae found on No lamellae found on the 1. No. of rows back (not mentioned in the lamellae (teeth) the dorsal surface dorsal surface 2. Height protologue). 1–2 cells Median leaf cells 1. Diameter 9–15 µm 10–15 µm Not mentioned 12–15 (–17) µm 2. Shape Rounded, quadrate to Rounded, quadrate Quadrate to irregularly irregular oval quadrate 3. Cell walls Thin-walled Thin-walled Thin-walled Basal cells 1. Length and width 18–25 × 8–16 µm 20–45 ×10–15 µm Not mentioned 53×9 µm 2. Shape (Irregularly) rectangular Rectangular Long, rectangular cells 3. Cell walls Slightly thick-walled Slightly thick-walled Not-mentioned Setae Reddish brown, straight Reddish brown, straight Straight Not-mentioned Capsule Not-mentioned 1. Shape Oblong-ovoid to shortly Ovoid - shortly Broadly ovate to cylindrical. cylindrical; asymmetric. inclined cylindrical. 2. Lid Shortly beaked. Shortly beaked. Conic with a short beak 3. Calyptra Cucullate, smooth with Cucullate, smooth with Cucullate, covered with several short cilia on the apex several short cilia on the sparse cilia. apex
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Peristome 32 32, single 27–33 ( mostly 32) with Not-mentioned brownish striations Spores 1. Shape Spherical Spherical Spherical Not-mentioned 2. Diameter 10 µm 9–15 µm 23–25 µm 3. Ornamentation Finely papillose Finely papillose Papillose
** O. glaciale C.C.Towns. was only described in the protologue which contains inadequate information about the taxon. At the time of describing the species no sporophytes were observed by the author. Hence, no sporophytic characters are mentioned in the literature
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1.5 Recent Molecular Taxonomic Studies on Oligotrichum.
Most of the molecular work done in past few decades has focused on the whole family Polytrichaceae with various exemplars of Oligotrichum chosen according to the purpose. Ivanova et al (2005) carried out research on the morphological and molecular differences between two arctic-alpine species of Oligotrichum, O. hercynicum and O. falcatum. Based on their observations, they tried to address the phytogeography and distribution patterns of two species. Moreover, from their study they explained that the morphology of these two species corresponds with six characteristic substitutions in the nrITS1 region, providing a robust backbone for delimitation of these two species. Furthermore, they explained that Oligotrichum hercynicum occurs in relatively oceanic climates in Northern Europe, the mountains of Central Europe, the Caucasus, Kuznetskij, Alatau in South Siberia, Kamchatka, Chukotka, and northern North America. By contrast, Oligotrichum falcatum has a Beringian distribution in the broad sense, being found in the mountains of South Siberia (westwards to Altai), Yakutia, xeric regions of North-East Asia and Arctic North America, including Western Greenland , and is also reported from Tibet.
A comprehensive molecular phylogenetic study of the moss class Polytrichopsida was carried out by Bell & Hyvönen (2010), providing convincing support for many traditionally recognised genera and identifying higher-level phylogenetic structure with a strong geographic component. Analysis of datasets including DNA sequences from the nuclear 18s rRNA gene, three chloroplast regions and the mitochondrial nad5 gene identified a large apical clade within the group that is most diverse in the northern hemisphere and is subtended by a grade of southern temperate and tropical genera, while the earliest diverging lineages were found to have widely separated relictual distribution patterns.Furthermore, they showed that Oligotrichum was polyphyletic, explaining that, "the large majority of Oligotrichum species sampled occur in one of two distantly related clades with predominantly northern and southern hemisphere distributions, respectively, implying convergent evolution of this morphology in each of the two temperate zones".
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These findings were expanded upon in a recent molecular study using the same genomic regions but focusing on the genus Oligotrchum specifically (Bell & Hyvönen, 2012). Based on the resulting tree topology, the authors again identified strong geographic patterning, with major groups having predominantly Northern or Southern Hemisphere distributions and some general morphologies having arisen independently on either side of the equator. They corroborated the earlier finding that the genus Oligotrichum DC. is a polyphyletic group, and discussed how this morphology has probably arisen through reduction on multiple occasions to produce distinct lineages that have lacked taxonomic identity. They presented a preliminary arrangement of the species currently recognized in Oligotrichum, placing some of the members of the Southern Hemisphere clade in Itatiella. Other Southern Hemisphere species were identified as not belonging to the predominantly Northern Hemisphere clade that includes the type species of Oligotrichum, although new combinations were postponed on the expectation that future analyses will provide more precise evidence of their relationships.
The Northern Hemipshere species, including the type species, O. hercynicum, and many of the Sino-Himalayan species such as O. aligerum, O. falcatum, O. falcifolium, O. obtusatum, and the unnamed collection from Pakistan all shared a highly reduced (56-59bp) P8 region in the trnL intron, which had previously been identified in all sampled Northern Hemisphere Oligotrichum species by Bell & Hyvönen (2010). Furthermore, the unnamed "Oligotrichum-like" plant collected by Terry Hedderson in Northern Pakistan occurred in an isolated clade together with the African Oligotrichum cavallii, outside the well-supported clade of Oligotrichum sensu stricto and apparently more closely related to Atrichum and Psilopilum. One of the aims of this taxonomic revision is to study and identify the taxonomic status of this unresolved Oligotrichum-like plant collected from Pakistan.
1.6 Phylogenetic Relationship of Oligotrichum with Closely Related Taxa
Smith (1971) separated the Southern Hemisphere Notoligotrichum from Psilopilum (both have northern arctic distributions) based on the distinctly different persitome teeth. He also mentioned that the peristomes of most Oligotrichum species from the Southern Hemisphere resemble those of Notoligotrichum rather than those of
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Northern Oligotrichum. He didn’t reclassify the Southern Hemisphere species Oligotrichum, although he clearly recognised that they differed from the northern species:“ The type elements of both Psiliopilum and Oligotrichum appear to be more closely related to one another that to many of the species in their respective genera, and the species, in turn, are evidently more closely related to one another than to the type species of the genus in which they now reside”.
A molecular study carried out by Bell & Hyvönen (2010) reported similar findings which agree with Smith’s study based solely on morphology. Bell & Hyvönen (2010) found strong support for the monophyly of a southern Hemisphere clade which includes Notoligotrichum, Itatiella, and some Oligotrichum species. Bell and Hyvönen (2010) explained that Oligotrichum is to some extent the “dustbin” genus of the Polytrichopsida, which lacks clearly defining characters found in other genera in the family, with reduction of adaxial leaf lamellae and absence of other important morphological features which give clues to taxonomic relationships. The results of Bell & Hyvönen (2010) suggest that this kind of reduced morphology in Oligotrichum has arisen at least twice; once as the probable plesiomorphic condition in a southern hemisphere group (from which Notoligotrichum is derived), and once in the ancestor of the distinct clade that comprises large northern hemisphere group (including the type species, O. hercynicum). Moreover, the phylogenetic study on Oligotrichum carried out by Bell & Hyvönen in 2012 provides a strong backbone phylogeny excluding the southern hemisphere taxa from the genus Oligotrichum.
Many of the characters distinguishing northern and southern Oligotrichum species are described by Smith (1971). In the southern clade, peristome teeth are single, narrow, pointed and well-separated. The teeth often project strongly inwards, towards the centre of the capsule and have an extended basal membrane; hence the entire peristome-epiphragm complex appears as a flat structure. This is a characteristic feature of most southern hemisphere Polytrichopsida (Dendroligotrichum and Polytrichadelphus) and may be a plesiomorphic character closer to the eperistomate disk of Alophosia and Lyellia (Bell & Hyvönen, 2010).
In the Northern Hemisphere clade, the peristome is mostly comprised of double teeth ( i.e. in some mosses, a peristome of two rings of teeth, an outer extome and an inner endostome), that are less narrowed and more crowded and upright. In the Southern
27
Hemisphere clade the distribution of stomata is highly restricted as a well-defined narrow band in the apophysis of the capsule, whereas in the Northern clade stomata are somewhat more scattered (Bell & Hyvönen, 2010, 2012). Finally, the southern taxa always lack abaxial leaf lamellae, whereas the northern species nearly always have some indication of these in addition to the normal adaxial lamellae. Notoligotrichum shares the above mentioned characters of the southern hemisphere Oligotrichum species; additionally it possesses some other characters including distinctly 2–3-angled capsules (whereas O.aligerum Mitt. has 4–5-angled capsules; Smith, 1971), that are usually curved and narrowed towards the apex, and generally bear a prominent band of stomata on the neck of the capsule (capsule base), and the broad costa usually supports a greater number of adaxial lamellae.
1.7 Oligotrichum DC. in Lam & DC. in the Sino-Himalaya
The genus Oligotrichum has not previously been revised for the Sino-Himalayan region. Different parts of the region have been included in various taxonomic publications covering neighbouring areas, such as the Moss Flora of China (Wu & Wang, 2005), the Bryoflora of the Hengduan Mountains (SW China) (Wu, 2000), the Bryoflora of Xizang (Li, 1985), and a revision of Polytrichaceae of Hengduan Mountains in China (Wang & Luo, 1994). Gangulee's taxonomic work on the moss flora of Eastern India and adjacent regions only included the single species Oligotrichum semilamellatum sensu lato (Gangulee, 1969).However, the Sino- Himalayan region is now known to be important for eight well-known and a few poorly-known species of Oligotrichum, including O. crossidioides, O. aligerum, O. falcatum, O. nepalense, O. obtusatum, O. semilamellatum, O. falcifolium and O. glaciale. Among these eight species, four of them, including O. aligerum, O. falcatum, O. obtusatum and O. falcifolium, are also reported from other countries outside the region (Gangulee, 1969, Long, 1985, Smith, 2007). Sixout of the eight accepted species encompass their type localities. Field work done by D.G. Long and several other botanists in the region in past 25 years has resulted in many new collections of the genus and almost all collections have been studied to revise the genus in the region.
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30
CHAPTER 02 MATERIALS AND METHODS
"The real purpose of the scientific method is to make sure nature hasn’t misled you into thinking you know something you actually don’t know." — Robert M. Pirsig , An Inquiry into Values
2.1 Material
This study was mainly based on herbarium material. Most specimens were collected by D.G. Long on expeditions to Nepal, Sikkim, Bhutan, Yunnan, Sichuan and Xizang during the past 25 years and are housed at the Royal Botanic Garden, Edinburgh (E). Additional herbarium specimens were obtained on loan from the Natural History Museum, London (BM), the Botanical Museum, University of Helsinki (H), Kunming Institute of Botany, Chinese Academy of Sciences (KUN), the New York Botanic Garden (NY), the Hattori Botanical Laboratory, Japan (NICH) and the Institute of Botany, Chinese Academy of Sciences, Beijing (PE). All specimens studied are cited under the taxonomic accounts of each species.
2.2 Light Microscopy
2.2.1 Observations and Measurements
Material was rehydrated with tap water for a few minutes to several hours (depending on its nature) and observed using a Wild Heerbrugg M5 dissecting microscope. Slides were prepared from rehydrated leaves mounted in water for temporary mounts and in glycerol for permanent mounts. From these, the leaf characters, including- leaf shape, leaf length and width, abaxial and adaxial leaf lamellae, and shape and size of median and basal leaf cells were observed and measured using a Zeiss AX10 compound light microscope.
Sporophyte characters were observed and measured using the dissecting microscope; spores were mounted on slides in Hoyer’s solution and observed using the compound microscope. Measurements were taken from five or more specimens with at least 10
29
leaves observed per specimen, taken from several stems. Leaf lengths were measured from the tip, down a central longitudinal axis. Leaf lamina widths were measured at the widest point, perpendicular to the length measurement.
2.2.2 Images
Leaves for photos and line drawings were mounted on slides in glycerine and ringed with nail varnish to preserve them. Photos were taken with an Axiocam MRc5 camera attached to a Zeiss Axiophot compound microscope using the Axiovision 4.8 software. Line drawings were made using the Zeiss Axioskop compound microscope with a camera lucida attachment.
2.3 Scanning Electron Microscopy (SEM)
Scanning electron microscope (SEM) observations were made of lamellae and sporophyte characters using a Supra 55VP LEO SEM. Whole dry leaves and capsules were transferred without treatment from herbarium specimens to 12 mm carbon discs mounted on 12.5 mm aluminium pin stubs. Specimens were coated with gold palladium using an Emitech K 575x sputter coater to a thickness of approximately 12 nm at a rate of 25 mA for 1.3 minutes.
2.4 Mapping
Distribution maps were produced using the information available from the specimen labels. When coordinates were not provided, geographic maps of the region, Google Earth and index gazetteers (GEOnet Names server http;//earth-info.nga.mil/gns/html/, Online Gazetteer of East Himalayan plant collecting localities http;//rbg- web2.rbge.org.uk/sikkim/sikgaz.htm) were used to obtain them. Longitude and latitude co-ordinates and approximate altitudes added by the author are in square brackets in the specimen lists. Species distribution maps were generated using ArcMap 10.1, ESRI, USA software. The base map of country and boundaries of provinces were downloaded from the Diva website (www.divagis.org/Data) and generated by Diva GIS 7.5.0 software.
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CHAPTER O3
TAXONOMIC REVISION
“Taxonomy is described sometimes as a science and sometimes as an art, but really it’s a battleground.” ― Bill Bryson, A Short History of Nearly Everything
3.1 Oligotrichum DC. in Lam. & DC., Fl. Franc. (ed. 3) 2: 491, 1805.
Syn.: Polytrichum Hedw. sect. Oligotrichum (DC.) Arnott, Mém. Soc. Linn. Paris 5; 322, 1827.
Syn.: Polytrichum Hedw. Subgen. Oligotrichum (DC.) Mont. in Orbigny, Dict. Univ. Hist. Nat. 8: 400, 1849.
Plants small to medium sized, greyish to blackish green, brownish green or reddish brown, erect, usually in lose tufts, gregarious. Stems simple, sparingly branched by innovations with numerous rhizoids at the base. Lower leaves small, scale-like to rather broad, distant, appressed to the stem. Upper leaves much larger, crowded, incurved, contorted or crisped when dry but sometimes curled or erect, spreading or falcate-secund when moist, lanceolate to oblanceolate or oblong-oval, closely appressed to stems, not clearly sheathing or slightly sheathing at the base, laminae flat or slightly to strongly incurved, apices acute or obtuse, margins involute, almost entire to denticulate or serrate in upper 1/3-1/2. Costae stout or narrow, well-defined, bearing lamellae on one or both surfaces; ventral lamellae few to many, sinuose, wavy or highly dissected, covering only costa or sometimes part of lamina, variable in height, in side view entire to slightly notched or irregular; dorsal lamellae tall or short, ridged or toothed. Laminae broad, unistratose, dorsal surface sometimes with low projecting lamelliform teeth; median cells rounded, oval, quadrate or irregularly subquadrate, thin-walled or slightly thickened; basal cells rectangular or irregular, slightly thick-walled. Sexual condition dioicous. Male plants smaller with shorter leaves than female plants, with discoid perigonium; perigonial leaves short, broad, spreading, apiculate; perichaetial leaves long and narrower, erect and smooth. Sporophytes occasional to frequent; setae elongate, erect; reddish brown. Capsules inclined or erect, cylindrical, ovoid-cylindrical or oblong-ovoid, symmetric or
31
asymmetric, with or without spongy apophysis at neck, greenish- brown, becoming black with age, old capsules often geniculate at neck, with large conspicuous cryptopore or phaneropore stomata at base. Operculum convex, with short or stout oblique beak. Peristome with 32 teeth, pale yellow to orange, simple, well separated, with brown striations. Calyptrae cucullate, brownish, with few scattered hairs or sometimes glabrous. Spores spherical, smooth to verrucose or papillose.
3.2 Key to Species of Oligotrichum in the Sino-Himalaya.
A. Leaf margin almost entire; leaves with strongly wavy ventral lamellae, 8–10 cells high; dorsal lamellae short, 1–3 cells high, present in both lamina and costa…………………………………………………………………. 1. O. crossidioides
+ Leaf margin slightly dentate, serrate or crenulate; leaves with slightly wavy, wavy to highly dissected ventral lamellae, 3–12(–15) cells high; dorsal lamellae absent, a few appear as rudimentary lamellae or rather tall with 3–6 cells high……………….…..….B
B. Dorsal lamellae tall, ventral lamellae (4–)6–10 cells high, margins of lamellae notched in side view………………………………………………………………..2. O. aligerum
+ Dorsal lamellae absent or appear as a few rudimentary lamellae or teeth, ventral lamellae 3–15, margins of lamellae entire, wavy to highly dissected in side view……………………………………………………………………………………...C
C. Leaves incurved and falcate to deeply cucullate when both dry and moist……………………………………………………………………….3. O. falcatum
+ Leaves erect, curled to cucullate when dry and mostly erect-patent when moist……………………………………………………………………………………..D
D. Leaves asymmetric; without clear sheathing base; oblong-oval to oblanceolate; ventral lamellae highly dissected, restricted to costa; 6(–10) rows, 8(–10)–15 cells high, basal leaf lamina cells comparatively small 5(–10) × 2.5–7.5µm in size……….4.O. nepalense
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+ Leaves almost symmetric with slightly or no clear sheathing base; lanceolate, oblanceolate to oblong-ovate ; ventral lamellae not dissected restricted to costa, 3–10 cells high, basal leaf lamina cells comparatively large 20–60 × 7.5-12.5µm in size…………………………………………………………………………..…………...E
E. Leaves oblong, oblong-ovate to oblanceolate, obtuse at apex, ventral lamellae slightly wavy, 3–8(–10) in rows; capsule oblong-ovoid to shortly cylindrical; spores ca. 10–12.5 µm in diameter……………………………………………………………5.O. obtusatum
+ Leaves lanceolate, narrowly- lanceolate to oblanceolate, acute to obtuse at apex; ventral lamellae wavy; capsule ovoid to shortly cylindrical; spores ca. 8–25 µm in diameter………………………………………………………………………………….F
F. Stem leaves rather long 2.5–4.5 × 0.5-0.8(–1.0) mm; ventral lamellae in 4–8(–10) rows, 4–6 cells high, highly variable in number; with very few rudimentary teeth on lamina of dorsal side of leaves; capsule cylindrical……...... 6. O. semilamellatum
+ Stem leaves rather short 1.8–2.5×0.7–1.0 mm; ventral lamellae in 4–12 rows, 3–9 cells high; dorsal side of leaves without rudimentary lamellae or teeth; capsule broadly ovoid to obovoid……………………………………………………………………………….G
G. Plants 0.5–1.5 cm tall; leaves lanceolate, narrow, width.0.8–1.0 mm and not concave; leaf apex acute; margins weakly serrulate in upper 1/3; ventral lamellae slightly wavy, 4–7 rows, 3–5 cells in height…………………………………………….7.O. falcifolium
+ Plants usually (0.5–) 0.8 (–1.0) cm tall; leaves oblong, rather broad, width 0.7 – 0.9 mm and profoundly concave; leaf apex obtuse ; margins very slightly dentate only at the apex; ventral lamellae very wavy, 6–10rows, 6–9cells in height……...... 8.O. glaciale
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3.2.1 Oligotrichum crossidioides P.-C. Chen & T.L. Wan ex W.X. Xu & R.L. Xiong.
Acta Bot. Yunnan. 6: 179, f.5, 1984. TYPE SPECIMEN: China. Yunnan, Lu-shui Co., Pianma Yakou, 3150 m, Z.-H. Hu 78097 (holotype YUKU, not seen; isotype KUN, not seen).
Figure 2, Map 2.
Stems brownish-green to reddish-brown, erect, 1.0–1.5 cm high, mostly in tufts and branching by innovations. Leaves mostly erect when dry and erect-patent when moist, lanceolate; stem leaves 2.5–3.5 mm × 0.2–0.5 mm, obtuse at apex, slightly sheathing at base; leaf margins almost entire; costa rather broad, often reaching apex; ventral lamellae confined to costa, strongly wavy, in 8–10(–12) rows, 4–6 cells high, dorsal lamellae both on lamina and costa, short, mostly 1–3 cells high; median leaf cells rounded, quadrate to irregularly quadrate, 8–10 µm wide, slightly thin-walled; basal cells rectangular, 20–30 (–32) × 8–12.5 µm, slightly thick-walled. Perigonial leaves in rosettes. Perichaetial leaves long, lanceolate, margins entire with both ventral and dorsal lamellae. Sporophytes occasional. Setae reddish brown, 10–15(–18) mm, straight. Capsules single, cylindrical, mostly curved; peristome teeth 32, single; Opercula with short beak. Spores 12–15(–16) µm in diameter.
Regional Distribution: China: Yunnan, Xizang. World distribution: Endemic to China (Wu & Wang, 2005).
Ecology: Commonly on rather wet soil along roadsides, forest ground and rocks (Wu & Wang, 2005); alt. ca. 2520–3600m.
Taxonomic Notes: This species was described as endemic to China in the Moss Flora of China (Wu & Wang, 2005). No type specimen was available for study but the distinctive leaves facilitated reliable identification. This species is quite similar to Oligotrichum aligerum Mitt, but O. aligerum differs in its serrate leaf margins and rather tall dorsal leaf lamellae on the costa.
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Specimens Observed:
CHINA, YUNNAN: Fugong County, Gaoligong Shan Range, southern end of the Hengduan Shan. Nu Jiang (Salween River) watershed, Yaping Pass road, 11.5 km above Shibali Forestry Field Station at bridge over river, 27° 12' 23.8"N, 98° 43' 05.0" E, 3300m, subalpine area along river with Fargesia (bamboo), Rhododendron and Abies on damp granite gravelly soil, 7 May 2004, Shevock & Fan 25567 (E); Gaoligong Shan Range, southern end of the Hengduan Shan. Nu Jiang (Salween River) watershed, Yaping Pass road, 6.4 km above Shibali Forestry Field Station at bridge over river, 27° 12' 42.3"N, 98° 44' 11.6" E, 2975m, open mixed hardwood forest with Fargesia (bamboo), Rhododendron and Acer ; on moist granitic gravels of roadbank,4 May 2004, Shevock & Fan 25400 (E); Gaoligong Shan Range, on the Western slope junction, 3400–3600m, growing on granite rocks, 26 May 1982, Wang 9470 (PE); [Dali County] Tsang (Cang) Shan: road to Longquan Peak above Dali [25° 43' N, 100° 04' E], 2520 m, pine forest slopes; on gravel bank by road. 15 October 1990, Long 19137 (E); Lushui County, Gaoligong Shan Range, southern of the Hengduan Shan, Irrawaddy river watershed, along road at km road marker 61 about 3 km below Fengxue Pass toward Pianma, 25° 58' 57.6"N, 98° 40' 0.9" E, 3035m, mixed hardwood forest with bamboo, on decomposed granitic sand and gravels of road bank in full sun, 19 May 2005, Shevock 26910 (E); Gaoligong Shan Range, southern of the Hengduan Shan, Irrawaddy river watershed, about 7 km west of Fengxue Pass at km road marker 65 along road to Pianma, 25° 58' 57.3"N, 98° 40' 25.7" E, 2800m, mixed hardwood forest dominated by Lithocarpus and Rhododendron, on exposed sunny granitic gravels of road bank, 16 May 2005, Shevock 26794(E).
CHINA, XIZANG [TIBET], Chayu, Songta Mountain, north side, from campsite to a narrow mountain pass, 3400–3600m, growing under a Rhododendron forest, 30 May 1982, Wang 8469 a, (PE), Wang 8469b (PE), Wang 8687 (PE).
35
Map 2. Distribution of Oligotrichum crossidioides in the Sino-Himalaya
36
0.5 mm cm 0.5 mm 0. 2 cm 0.5 mm
0.25 cm
cm 3
4
5 6
0. 5 cm
2
7 1
25 µm cm
9 8 25 µm 35 µm cm cm
10 20 µm 20µm cm Figure 2. Oligotrichum crossidioides 1, Habit moist; 2, Habitm cm dry; 3,Capsule with seta; 4, Stem leaf in dorsal view; 5, Stem leaf in ventral view; 6, Perichaetial leaf in ventral view; 7, Lamellae in side view; 8. Basal cells of leaf lamina; 9. Median cells of leaf lamina; 10, Cross-section of leaf. (1-10, drawn from Wang 8469a, b, Wang 8687 (PE)).
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3.2.2 Oligotrichum aligerum Mitt.
J. Proc. Linn. Soc., Bot. 8: 48, pl.8, 1864. TYPE SPECIMEN: [Canada, Alberta] Grande Cote, Rocky Mountains, T. Drummond 448 (holotype, NY, not seen; isotype, NY, not seen).
Figure 3, Map 3.
Stems greenish-brown to reddish-brown, erect, 0.5–1.5 cm high, mostly in tufts and sparingly branched by innovations. Leaves often crisped when dry, erect-patent when moist, lanceolate; stem leaves (2.5–)2.7–3.0(–3.3) × 0.3–0.5 mm, acute to acuminate at apex, slightly sheathing at base; margins serrate or serrulate; costa rather broad, often reaching at the apex, ending in a short apiculus; ventral lamellae confined to costa, slightly wavy, in 6–8(–10) rows, (4–)6–10 cells high; dorsal lamellae both on lamina and costa, short 2–4 cells high, mostly 1–3(–4) cells high; median leaf cells quadrate to irregularly quadrate, (8–)10–15µm wide slightly thin-walled; basal cells rectangular, 25–38(–40) × 10–15 µm, slightly thick-walled. Perigonial leaves in rosettes. Perichaetial leaves long with a wide sheathing base, lanceolate. Sporophytes not seen.
Regional Distribution: China: Yunnan. World Distribution: China, Japan, Korea, Taiwan, Philippines (Noguchi, 1987), North America (Noguchi, 1987, Smith, 2007) and Central America (Noguchi, 1987). O. aligerum was reported from Bhutan (Noguchi, 1971) but Smith (1976) showed that this was based on a misidentification of O. semilamellatum.
Ecology: commonly on moist soil, along road sides, forest ground, or rocks (Wu & Wang, 2005); alt. 2150–3200 m
Taxonomic Notes: In the protologue, Mitten (1864) commented “In size and general appearance like O. hercynicum, for which species it was overlooked by Drummond himself; but its leaves are narrower, and when dry more crisped, and the presence of the lamellae on the underside of the leaf itself, as well as upon both sides of the nerve, is remarkable and peculiar”.
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Specimens Observed:
CHINA, YUNNAN: Lushui County, Pianma frontier inspection station [26° 00’ N, 98° 36’ E], 2150–3200 m, 27 May 1982, Wang & Lou 811918 (PE).
Map 3. Distribution of Oligotrichum aligerum in the Sino-Himalaya.
39
0.4 mm 0.4 mm
0.25 cm
0.25 cm 1
2 3 4
5 80 µm
6 7
20 µm 20 µm
8
80 µm
9 60 µm Figure 3. Oligotrichum aligerum. 1, Habit, moist; 2, Male plant with perigonial leaves; 3, Stem
leaf in ventral view; 4, Stem leaf in dorsal view; 5, Basal cells of leaf lamina; 6, Median cells of leaf lamina; 7, Leaf margin; 8, Lamellae in side view; 9, Cross-section of leaf. (1-9, drawn from Wang & Lou 811918, (PE)). 40
3.2.3 Oligotrichum falcatum Steere.
Bryologist 61: 115, .f. 1–9, 1958. TYPE SPECIMEN: [USA], Alaska, Mt Michelson Quad., Peters Lake, 1952, Steere 18959 (holotype, NY, not seen; isotypes, E, seen, ALTA, C, FH, NY, not seen).
Syn.: Psilopilum falcatum (Steere) H.A. Crum, Steere & L.E. Anderson, Bryologist 68: 434, 1965 [1966].
Figure 4, Map 4.
Stems silvery green, reddish-brown with age, erect, 1.5–2(–5) cm high, simple to much branched by innovations. Leaves often strongly falcate-secund in both dry and moist conditions; ovate-lanceolate, stem leaves 1.5–3.0 × 0.6–1.0 mm, acute at apex, slightly sheathing at base; margins remotely denticulate or almost entire but mostly with several larger teeth just below the apex; costa rather broad, often reaching at the apex; ventral lamellae confined to costa, slightly wavy, in 9–12(–14) rows, 6–10 cells high, in side view irregularly lobed and notched; laminae with low teeth or lamellae on dorsal surface only near apices; median leaf cells quadrate to irregularly quadrate, 8–15(–18) µm wide, slightly thin-walled; basal cells rectangular, 15–25(–30) × 10–15 µm, thick-walled. Perigonial leaves spreading, broadly ovate or suborbicular. Perichaetial leaves long, lanceolate, almost straight. Sporophytes rare, not seen
Regional Distribution: China: Xizang (Tibet); India: Sikkim; Nepal. World Distribution: China, Himalayas (Wu & Wang, 2005); North America: USA, Alaska (Long, 1985; Smith, 2007); Greenland (Long, 1985, Ivanova et al., 2005, Wu & Wang, 2005); Canada: Labrador, Yukon (Long, 1985, Ivanova et al., 2005); Russia: Siberia and Russian Far East (Ivanova et al., 2005). New to India and Nepal.
Ecology: An acidophilous species (Ivanova et al., 2005), in silvery-green patches on moist meadows, and rocky substrates (Long, 1985, Wu & Wang, 2005); in Sino- Himalaya confined to very high altitudes, 3900–4460 m.
Taxonomic Notes: O. falcatum can be distinguished from the more widespread northern species O. hercynicum (which is excluded from the study area) by the regular falcate-secund leaves, with scarcely developed abaxial lamellae. In the protologue, Steere mentions that “in the field, the submerged plants have a beautiful pale silvery-
41 green appearance, from the air trapped in the large dorsal cell layer of the costa”. Further, he considers that the generic position of the species can be clarified only when the sporophyte is discovered. In the absence of sporophytes the species was first placed in the genus Oligotrichum, and then transferred to Psilopilum (Crum et al., 1965). But in 1960 a few capsules were discovered by William Steere, Olle Mårtensson and Kjeld Holmen at the original habitat (Steere & Smith, 1975). These indicated that the original generic placement had been correct. In summer 1974, Steere and Zen Iwatsuki discovered a large population of O. falcatum with abundant sporophytes several kilometres away from the original locality. This discovery enabled a more detailed description of the sporophyte of O. falcatum to be made (Steere & Smith, 1975).
Specimens Observed:
CHINA, XIZANG (TIBET): southern slope of the Duoxiongla Mountain [29° 21' N, 95° 21' E], 3900 m, 24 June 1980, Wang 800071b (PE), northern slope of the Duoxiongla Mountain [29° 21' N, 95° 21' E], 3900 m, 24 June 1980, Wang 800061-1 (PE).
INDIA, SIKKIM, WEST DISTRICT: East slopes of Prek Chhu valley, west facing cliffs NE of Thangshing, 27° 31' N, 88° 12' E, 4420 m, mossy boulder scree below cliffs, on wet cliff ledge, 24 July 1982, Long 22859 (E),
NEPAL, TAPLEJUNG DISTRICT, north side of Mirgin La, 27° 33' N, 87° 57' E, 4460 m, open rocky hillside, on side of path, 16 September 1989, Long 17001 (E).
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Map 4. Distribution of Oligotrichum falcatum in the Sino-Himalaya.
43
0.4 mm 0.4 mm
3 0.20 cm 4 0.20 cm
1 0.4 mm 2
30 µm
5
8 30 µm
7 25 µm 6
9 30 µm
30 µm 11
10 30 µm
Figure 4. Oligotrichum falcatum 1, Habit, dry; 2, Habit, moist, showing innovation; 3, Stem leaf in dorsal view; 4 & 5, Stem leaves in ventral view; 6, Leaf margin with a part of lamina; 7, Side view of leaf lamellae; 8, Leaf apex; 9, Median cells of leaf lamina; 10, Basal cells of leaf lamina; 11, Cross section of leaf.. (1–11, drawn from Wang 800071b (PE)).
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3.2.4 Oligotrichum nepalense G.L. Sm.
J. Hattori Bot. Lab. 41: 420, f. 1–9, 1976. TYPE SPECIMEN: Nepal [East Nepal, Sankhuwasabha District], Kipuphu to Phujeng La [27° 40' N, 87° 35' E], 4600 m, on soil, 27 June 1972, Iwatsuki, 1722 (holotype, NICH, seen; isotype, NY, seen).
Figure 5, Map 5.
Stems brownish green to reddish brown, long and slender, 0.5– 1.0 cm high, simple and rarely branching. Leaves markedly concave, asymmetric, falcate-second when dry and less patent when moist, oblong oval to oblanceolate; stem leaves 1.0(–1.3) mm × 0.5(–0.6) mm, acute at apex, no clear sheathing at base, remotely serrulate ; costa rather broad, often reaching apex; ventral lamellae confined to costa, with very characteristic, highly dissected lamellae in 6(–10) rows,(8–)10–15 cells high, dorsal lamellae rudimentary, irregularly spaced, both on costa and lamina, very short, 1–2 cells high; median leaf cells rounded, quadrate to irregularly oval, 2.5–5.0 µm in diameter, slightly thin-walled; basal cells rectangular, 5(–10) × 2.5–7.5 µm, slightly thick -walled. Sporophytes not seen.
Regional Distribution: East Nepal (Sankhuwasabha district). World distribution: Endemic to Nepal (Smith, 1976).
Ecology: Grows at high altitude, alt. 4600 m.
Taxonomic Notes: This is a very distinct species due to its unique, highly dissected ventral lamellae on the costa. Smith mentions in his protologue that, “this new species is unmistakably allied to Oligotrichum falcatum Steere, of Arctic Alaska, Canada and Greenland”. Only known from the type specimen which lacks sporophytes.
Specimens Observed:
NEPAL, [SANKHUWASABHA DISTRICT], Kipuphu-Phujeng La, [27° 40' N, 87° 35' E], 4600 m, on soil, 27 June 1972, Iwatsuki 1772 (NICH, NY).
45
Map 5 :
Map 5. Distribution of Oligotrichum nepalense in the Sino-Himalaya.
46
0.5 mm 0.5 mm
0.2 mm
3 2
25 µm
5 µm 1
10 µm
5 6 4
8
10 µm 25 µm 7
25 µm
10 9 25 µm Figure 5. Oligotrichum nepalense 1, Dry habit; 2, Stem leaf in ventral view; 3, Stem leaf in dorsal view; 4, Median leaf cells with leaf margin; 5, Median leaf cells 6. Basal leaf cells; 7, Highly dissected ventral lamellae in side view; 8, Cross-section of leaf lamina, lower 1/3 of the leaf, with rudimentary tooth on dorsal side; 9, Dorsal surface of leaf lamina with lamellae from above, upper 1/3 of leaf; 10, Cross section of the leaf. (1–10 drawn from Iwatsuki 1722 (NY)). 47
3.2.5 Oligotrichum obtusatum Broth.
Symb. Sin. 4: 133, 1929. TYPE SPECIMEN: China, Yunnan [Heqing County] the village Hsianschuiho [=Xiangshuihe], between Dali (Talifu) and Hodjing [=Heqing], 26° 15’ N, [26° 15' N, 100° 07' E], ca. 3400 m, 25 May 1915, Handel-Mazzetti 6505 (holotype, H-BR, seen).
Figure 6, Map 6.
Stems brownish green to reddish brown, erect, 0.5–1.5 cm high, often with tufts of leaves, unbranched. Leaves incurved when dry, erect-patent when moist, oblong-ovate to oblong-lanceolate, usually concave; stem leaves 1.4–1.7 × 0.5–0.7 mm, obtuse at apex, slightly sheathing at base; margins serrate; costa rather broad, often reaching apex; ventral lamellae confined to costa, slightly wavy; usually in 3–8(–10) rows, 5–6 cells high; dorsal lamellae absent or with very few spines, irregularly spaced; median leaf cells rounded, quadrate to irregularly oval, 10–12(–15) µm wide, slightly thin- walled; basal cells rectangular, 20–25 × 8–12.5 µm, slightly thick-walled. Perichaetial leaves long, lanceolate, concave, 2.5–3.1 × 0.6–0.8 mm, sheathing at base, with lamellae on the ventral side. Setae reddish brown, straight, 20–30 mm long. Capsules oblong ovoid to shortly cylindrical, curved; peristome teeth 32, single; opercula conic, shortly beaked. Spores spherical, 10–12.5 µm in diameter.
Regional Distribution: China: Yunnan, Sichuan; India: Sikkim, West Bengal; Nepal. World distribution: China, Taiwan, India, Nepal, (Wu & Wang, 2005). New to India and Sichuan.
Ecology: on wet substrates along road sides, forest grounds, rocky valleys, or rocks in high elevations; alt. 2080–4350 m.
Taxonomic Notes: Sometimes in the field this species has been confused with the more polymorphic species Oligotrichum semilamellatum (Hook.f.) Mitt., hence many earlier collectors misidentified this species as O. semilamellatum. But the obtuse leaf apex and oblong-oval shape of basal leaves of O. obtusatum help to overcome this misidentification.
48
Additional Specimens Observed:
CHINA, YUNNAN: Malong County, Nazhang community, Fanglang sub-branch, Puqi village, Niutoushan (Ox-head mountain) [25° 25' N, 103° 34' E], ca. 2300m, on top of a mountain, 16 Nov 1979, Zhu 7905 (KUN); Tengchong County, Gaoligong Shan (Kaolikung Mountain), 2300m, on damp soil, Hsu 10 (E); Gaoligong Shan, Nu Jiang (Salween river) watershed, ca. 2300 m, by the slope of a cliff near forest, 23 July 1956, Practice Team 2 (KUN); Jingdong County, Wuliang Mountain, Baizhulinpo (white bamboo wood slope), [24° 26' N, 100° 41' E], ca. 2750 m, on soil in Rhododendron forest, 09 December 1979, Zhu 79044-2 (KUN); Nanjian County: Baohua Zheng, Wuliangshan national nature reserve, somewhere about 1km from Sheyaoqing management station, 24° 45' 54'' N, 100° 30' 29'' E, ca. 2273 m, on soil by road side, 23 March 2012, Ma 12-2914 (KUN); Zhongdian County, Tian Shu Lake above Xiaozhongdian, 27° 37' N, 99° 38' E, 3825 m, slopes by lake; peaty bank under Rhododendron by pool, 13 June 1993, Long 24300 (E); Zhongdian County, Na Pa Hai forest [27° 53' N, 99° 38' E], 3500m, on bank of track in cleared Picea forest, 28 September 1990, Long 18635 (E); Yulong County, Yulong Shan, valley above Wo Tu Di [27° 02' N, 100° 11' E], 3790 m, rocky mountain valley, on soil at base of rock face, 10 October 1990, Long 19013 (E); Xinping County, east side of the downtown county, [24° 04' N, 101° 59' E], ca. 2080 m, below a tree growing near rocks, 09 August 1979, Zhu 7908 (KUN).
CHINA, SICHUAN: [Emeishan County], Emeishan mountain, near the Yongqing Temple [29° 31' N, 103° 19' E], on soil by roadside, 07 September 1939, Dai T-109 (PE).
INDIA, SIKKIM: West District: between Thangshing and Lam Pokhari, E side of the Prek Chhu valley, 27° 30' N, 88° 11' E, 3965 m, dense Rhododendron scrub, on rocky peaty bank, 19 July 1992, Long 22682 (E); Sikkim, without locality, 10-11,000 ft [ca. 3353 m], Kurz 2258 (NY).
INDIA, WEST BENGAL, [DARJEELING DISTRICT]: around Dak Bangalow, Tongloo 27° 02' N, 87° 04' E, 10,000 ft. [ca. 3048 m], on cliff, 25 April 1965, Iwatsuki & Sharp 9663 (NY).
49
NEPAL: [Sankhuwasabha District], between Topke Gola and Shewaden, [27° 37' N, 87° 35' E], 3350m, on bank, 28 June 1972, Iwatsuki 1830 (NY); between Thudam and Kipuphu, [27° 43' N, 87° 33' E], 3900 m, on soil, 26 June 1972, Iwatsuki 1666 (NY); between Lama Chungu and Slesa, [27° 47' N, 87° 37' E], 4350 m, on soil, 24 June 1972, Iwatsuki 1598 (NY); Taplejung District, N slopes of Deorali Danda between Simbua Khola and Omje Khola, 27° 29' N, 87° 54' E, c. 3000m, Mossy Tsuga forest, on soil bank by path, 22 September 1989, Long 17156 (E).
Map 6. Distribution of Oligotrichum obtusatum in the Sino-Himalaya.
50
0.4 mm
20 µm
50 µm
5
0.5 mm 0.4 mm
6
4 3 0.3 mm
2 7 50 µm
8
50 µm
1
9 50 µm Figure 6. Oligotrichum obtusatum 1, Habit, moist, with capsule; 2, Stem leaf in ventral view; 3, Perichaetial leaf in ventral view; 4, Perichaetial leaf in dorsal view; 5, Leaf apex
with lamina cells; 7, Basal cells of leaf lamina; 8, Median cells of leaf lamina; 9, Cross
section of leaf. (2-4 drawn from Handel-Mazzetti 6505 (H-BR); 1, 6–9 drawn from Iwatsuki 1666, (NY)). 51
3.2.6 Oligotrichum semilamellatum (Hook.f.) Mitt., J. Linn. Soc. Bot. Suppl. 1: 150, 1859.
Basionym: Polytrichum semilamellatum Hook.f., Hook. Icon. Pl. 2: 194 A, 1837 and J. Bot. 2: 3, 1840. Locality given in Harvey & Hooker (1840): Himala Mountains. TYPE SPECIMEN: [NW India, Uttarakhand], Urukta, [approx. 31° 02’ N, 77° 49’ E], Royle 1363 (lectotype BM, seen, isolectotype BM, seen, isolectotype LIV, not seen); lectotypified by Long (1995).
Syn: Oligotrichum aristatulum Broth., Symb. Sin. 4: 132, 1929. TYPE SPECIMEN: China, Yunnan [Gongshan County], east side of Tsiangschel pass between Lu-djiang (Salwin) and Djiou-djiang (Irrawadi), [27° 52' N, 98° 25' E], 3300 m, on wet mica- schist cliffs, Handel-Mazzetti 9528 (holotype, H-BR, seen); syn .nov.
Syn: Oligotrichum semilamellatum var. darjeelingense Gangulee, Mosses of Eastern India and adjacent regions 1: 84, f.34, 1969. TYPE SPECIMEN: India, Darjeeling, Gangulee 3579, (holotype, Herb. Gangulee, not seen); syn. nov.
Syn: Oligotrichum semilamellatum var. edentatum Gangulee, Mosses of Eastern India and adjacent regions 1: 87, f.35, 1969. TYPE SPECIMEN: India, Sikkim [locality unknown], 2438 m, Kurz 2366 (holotype, BM, seen); syn. nov.
Figure 7, Map 7
Stems brownish green to reddish brown, erect, medium sized, 1.0–2.5 (–3.0) cm high, mostly scattered. Leaves recurved when dry and erect-patent when moist, lanceolate; stem leaves 2.5–4.5 × 0.5–0.8(–1.0) mm, acute to acuminate at apex, slightly sheathing at base; margins slightly dentate to serrate; costa rather broad, vanishing below the apex; ventral lamellae confined to costa, slightly wavy, in 4–8(–10) rows, 4–6 cells high; dorsal lamellae absent or with a very few rudimentary lamellae (teeth) on lamina, short, mostly 1–2 cells high; median leaf cells rounded to quadrate, 10–12 (–15) µm wide, slightly thin-walled; basal cells rectangular, 20–45 × 8–10 µm, slightly thick-walled. Perigonial leaves in rosettes. Perichaetial leaves long and slender, with lamellae. Sporophytes frequent. Setae reddish brown, 12–30 mm long, straight or sometimes slightly curved. Capsules single, erect to inclined, cylindrical, 3.5–4.0 mm long and 1.8–2.0 mm in diameter; peristome teeth 32, single, slightly developed to well-developed peristome membrane. Opercula with short beak. Spores pale yellow to brown, comparatively small, 8–12 µm in diameter.
52
Regional Distribution: Nepal; India: Uttarakhand, West Bengal, Sikkim; Bhutan; China: Yunnan. World Distribution: Endemic to Sino-Himalaya (Nepal to Yunnan). Also reported from Xizang (Tibet) by Xu & Xiong (1985).
Ecology: on forest ground, moist soil along road sides, river banks or on rocks; alt.: 1470–3353 m.
Taxonomic Notes: The typification of Polytrichum semilamellatum Hook.f. was clarified by Long (1985).
Oligotrichum semilamellatum is one of the most widespread and morphologically variable species of the genus in the study area. Leaf characters are very plesiomorphic. This species can easily be confused with the related species O. falcifolium (Griff.) G.Sm. in the field and many earlier collectors misidentified O. falcifolium as O. semilamellatum. Smith (1971, 1972) discussed the confusion between these two species. However, my observations suggest that capsule shape, spore size and the ventral lamellae morphology (to a certain extent) are reliable diagnostic vegetative characters to distinguish between O. semilamellatum and O. falcifolium. (See also Table 3 in Chapter 4). Though Smith (1971,1972) mentioned this species as being apparently rare, recent expeditions by Long show that this is not the case, with many collections from China (Yunnan) and Nepal at higher altitudes.
O.aristatulum Broth., synonymised above, has up to now been regarded as a poorly- known taxon. Brotherus (1929) distinguished it from O. semilamellatum sensu lato by its entire, aristatulate leaves. Though the holotype (H-BR) comprises only a few leaves and capsules which are in poor condition, after careful examination of the available material, it is concluded that they fall within the morphological range of O. semilamellatum. In the protologue, Brotherus (1929) described the leaves as “…superior elongate lineari-lanceolata, aristatula…” which implies the upper leaves (i.e. perichaetial leaves) have pointed aristatulate apices rather than the stem (basal) leaves. This is not a very informative taxonomic character to distinguish an Oligotrichum species because in all species the perichaetial leaves have rather different morphologies from the normal basal leaves. Since the holotype is in poor condition the potentially diagnostic leaf apices are mostly missing. Even though, Smith (1972) mentioned that the capsules of O. aristatulum have Notoligotrichum- like characters with sunken stomata in the capsules, a comparative microscopic study
53 done for O. semilamellatum, O. falcifolium and allied taxa reveals that O. aristatulum has phaneropore (superficial) stomata typical for most Oligotrichum species including O. semilamellatum rather than cryptopore (sunken) stomata (see also further discussion in Chapter 4).
Additional Specimens Observed:
INDIA, [WEST BENGAL], DARJEELING DISTRICT: Kurseong, [26° 52' N, 88° 17' E], 5500 ft. [1676 m], 30 September 1899, Decoly & Schaul s.n. (H-BR); Phalloot [27° 13' N, 88° 01' E], 11000 ft. [3353 m], 16 October 1868, Kurz 2333 (H-BR); Phalloot [27° 13' N, 88° 01' E], 10000 ft [3048 m], s.d., Kurz 2101 (BM); Phalloot, [27° 13' N, 88° 01' E], 10–11000 ft. [3048–3352 m], s.d., Kurz 2257 (BM); Phalloot, [27° 13' N,88° 01' E], 10–11000 ft. [3048–3352 m], s.d., Kurz 2257 (BM, NY); Darjeeling [27° 02' N, 88° 15' E], 1911, Mrs Rouper 51 (BM); Darjeeling [27° 02' N, 88° 15' E], 1954, Chopra & Singh 14 (BM); Darjeeling; Birch Hill, [27° 03' N, 88° 15' E], on moist ground, 24 August 1960, Gangulee 5070 (BM); Sinchul [26° 59' N, 88° 17' E], 8600 ft. [2621 m], Nov. 1881, Levinge s.n. (BM); Senchal Lake, Tiger Hill, [26° 59' N, 88° 17' E], 2500m, 16 April 1960, Hara et al. 200575 (NY); 5 km west of Sukia Pokhari, west of Ghum, 26° 59' N, 88° 09', ca. 2120 m, open degraded hillside; on crumbling roadside, 5 August 1992, Long 23038 (E),
INDIA, SIKKIM: without locality, 8000 ft [2438 m], Kurz 2366 (BM); Nathu La, [27° 23' N, 88° 50' E], 15000 ft, 4572 m, Ribu in Herb. Levier 7924 (BM, H-BR); Sikkim Himalaya, Hooker 1238 (BM); [North District], Toomling [=Tumlong], [27° 25' N, 88° 50' E], 1000 ft. [305 m], 20 August 1901, Hartless 2670 (BM, H-BR); East District, Fambong Lho Forest above Pangthang, North of Gangtok, 27° 21' 15" N, 88° 36' 04" E, ca. 2130 m, degraded evergreen oak forest, on gravelly side of footpath, 5 July 1996, Long 26271 (E).
INDIA, [UTTARAKHAND]: Kumaon, Gori River [29° 45' N, 80° 22' E], 12,000 ft. [3658 m], 16 August 1900, Kabir Khan 1912 (E, H-BR).
NEPAL: Kaski District, two day's trek Northeast of Sikles village, on slope above the Muckyun River, [28° 13' N, 84° 06' E], 3150 m, in Abies spectabilis/ Rhododendron barbatum, R. campanulatum forest, growing on soil, 30 August 2001, Allard & Neupane 1761 (BM); [Kaski District] Rambrong Ridge, [28° 22' N, 84° 12' E], 11,000
54 ft [ 3352 m], 27 April, 1954, Stainton, Sykes & Williams 5092 (BM); Sankhuwasabha District, south slopes of Pawa Khola, west of Panch Pokhari Khola, 27° 35' N, 87° 24' E, ca. 2055 m, margin of forest, on bank of path, 17 October 1991, Long 21268 (E); between Shidua and Tashigaon, 27° 36' N, 87° 16' E, ca. 1960 m, Castanopsis scrub, on damp rocky bank, 23 September 1991, Long 20511 (E); Rasuwa District, Langtang Khola between bridge and Bamboo Lodge, 28° 09' N, 85° 24' E, ca. 1995 m, mossy evergreen oak forest on river bank, on unstable earthy bank, 16 October 2001, Long 30650 (E); [Solukhumbu district], Chauri Kharka [near Lukla], [27° 41' N, 86° 43' E], 2670 m, 27 November 1954, Zimmermann 1867 (BM); [Taplejung District], Milke Danda Forest [27° 26' N, 87° 28' E], 9000 ft [2743 m], 26 October 1961, Norkett 6584-b (BM).
BHUTAN: Bhotan, without locality, [1838], Griffith 782 (H-BR, BM).
CHINA, YUNNAN: Dali County, Tsang (Cang) Shan, top of road to Longquan Peak above Dali [25° 43' N, 100° 04' E], ca. 3135 m, open scrubby degraded hillside, on soil of road cutting, 15 October 1990, Long 19139 (E); Shu Ching Qan valley NW of Huadianba [25° 53' N, 100° 00' E], ca. 2885 m, densely wooded valley with Lithocarpus and Rhododendron sino-grande, on shady rock face by stream, 17 October 1990, Long 19230 (E); Fugong County, Lishadi Xiang, Yaduo Cun, East slope of Gaoligong Shan (Nu Jiang catchment), north bank of North Fork Yamu River, along road 1 km below Shibali Forestry Station, 27° 09' 50.9"N, 98° 46' 56.7" E, ca. 2475 m, evergreen Castanopsis forest on south-facing valley slope, on gravelly bank of road cut, 07 August 2005, Long 34449 (E); Gongshan County, Gaoligong Shan Range, southern end of the Hengduan Shan, Nu Jiang (Salween river) watershed, Dulong Road, tributary of Pula He at Daladi site, 41 km from Gongshan (17 air miles west), 27° 47' 39.7" N, 98° 30' 12.1" E, ca. 2970 m, open mixed hardwood conifer forest of Acer, Abies and scattered Larix, on gigantic gravels and rock along road bank, 28 September 2002, Shevock 23136 (E); Tengchong County, middle way from Datang to Dahetou, 25° 43.568' N, 98° 41.599' E, 1950 m, on clay in slope, 15 May 2006, Li 4571 (E); Qushi Xiang, Yong'an Cun, Longchuan Jiang valley, east fork of Longchuan Jiang at Yonganqiao, 25° 19' 29" N, 98° 36' 33" E, ca. 1470 m, river bank with exposed granite rocks and scrub, on shady gravel bank of road cutting, 22 October 2003, Long 32518 (E); Shangying Xiang, Datianpo Cun, west slope of Gaoligong Shan at Dahaoping, on road from Bawan to Tengchong, 24°
55
58' 18" N, 98° 43' 48" E, ca.2064 m, roadsides near habitation with remnants of evergereen oak forest, on soil covered rocks by water channel, 17 October 2003, Long 32369 (E); without locality, s.d., Delavay 1632 (BM).
Map 7. Distribution of Oligotrichum semilamellatum in the Sino-Himalaya
56
0.4 mm 0.5 mm 0.4 mm
0.5 mm
0.6 mm
4
3
5 2
12 µm 12 µm
1 6
12 µm
8 7
9
12 µm 10 12 µm
Figure 7. Oligotrichum semilamellatum 1, Habit, moist; 2, Perichaetial leaf in ventral view; 3, Perichaetial leaf in dorsal view; 4, Stem leaf in ventral view; 5, Stem leaf in dorsal view; 6, Median leaf cells of lamina; 7, Basal leaf cells of lamina; 8, Leaf margin; 9, Lamellae in side view; 10, Cross-section of leaf. (1–5 drawn from Royle 1363 (BM), 6–10 drawn from Long 57 26271 (E)).
3.2.7 Oligotrichum falcifolium (Griff.) G.L. Sm.
Phytologia 18: 403. 1969.
Basionym: Polytrichum falcifolium Griff., Calcutta J. Nat. Hist., 2: 475, 1842. TYPE SPECIMEN: [India], Assam, Boga Panee, Khasi Hills [27° 26' N, 95° 37' E], [c. 1400 m], Griffith s.n. (holotype, BM, seen; isotype, BM, seen).
Syn: Oligotrichum semilamellatum var. falcifolium (Griff.) Gangulee, Mosses of Eastern India and adjacent regions 1: 88, f. 34, 1969.
Figure 8, Map 8
Stems brownish green to reddish brown, erect, medium sized, 0.5–1.5 cm high, mostly scattered. Leaves curled and incurved when dry and erect-patent to slightly falcate when moist, lanceolate; stem leaves 1.8–2.0(–2.2) × 0.8–1.0 mm, acute at apex, slightly sheathing at base; margins irregularly involute, sub-denticulate in upper 1/3 to 1/2; costa rather broad, often reaching apex; ventral lamellae confined to costa, slightly wavy, in 4–7 rows, 3–5 cells high, dorsal lamellae absent; median leaf cells rounded to quadrate, 12.5–17.5 µm wide, slightly thin-walled; basal cells rectangular, 35–60 × 7.5–12.5 µm, slightly thick-walled. Perigonial leaves in rosettes. Perichaetial leaves long with comparatively large slightly sheathing base, lanceolate; margins entire to slightly dentate in upper 1/3; lamellae present on costa of ventral side. Sporophytes frequent. Setae reddish brown, 20–40 mm. Capsules inclined, broadly ovoid-cylindrical, 2.2 × 1.5 mm; peristome teeth 32, single. Opercula with very short beak. Spores dark brown, comparatively larger, papillose, 23–25 µm in diameter.
Distribution: India: Assam, West Bengal and Sikkim; Nepal. Restricted to India and Nepal. World Distribution: India, Nepal, Philippines (Iwatsuki & Tan, 1980; Tan & Iwatsuki, 1991).
Ecology: on forest ground, moist soil and banks or on hills and rocks; alt: 1720–3550 m.
Taxonomic Notes: This is also a highly variable species in the study area and has been confused in the past with O. semilamellatum (Smith 1971, 1972; Bell & Hyvönen, 2012). During the 19th century many botanists distinguished Polytrichum
58
(Oligotrichum) semilamellatum from Polytrichum (Oligotrichum) falcifolium using leaf characters. On the isotype of P. falcifolium Griff. in Hooker’s herbarium (Herb. Hooker 1238, BM), J.D. Hooker made an annotation “this species is different from P. semilamellatum Hook.f.” In 1874, W. Wilson annotated the same specimen as having “flattened leaves, not serrated, areoles [cells] rather larger, lamellae few”. On the holotype specimen (Griffith s.n., BM) Griffith noted “leaves lanceolate to subulate, sub-denticulate, very obscurely lamellated, incurved; capsule sub- rotund, inclined”. Capsule shape and the spore size are other useful characters to distinguish between O. falcifolium and O. semilamellatum in addition to the size and number of ventral leaf lamellae. (For further details see under O. semilamellatum and discussion in Chapter 5).
Additional Specimens Observed:
INDIA, WEST BENGAL, DARJEELING DISTRICT: Sandakphu – Kala Pokri – Garibans – Tonglu [27° 06' N, 88° 00' E], 2600–3550 m, 7 June 1960, Hara et al. 200641 (H); Ghoom Ridge [27° 00' N, 88° 15' E], 7000 ft, [2134 m], 28 October 1900, Hartless in Bryotheca E. Levier 2274 (H-BR, BM, NY); Senchal [Sinchul] [26° 59' N, 88° 17' E], 8000 ft. [2438 m], 29 October 1900, Hartless 2276 (BM, NY); Ranbi forest near Darjeeling [26° 59' N, 88° 16' E], ca. 7400 ft. [2256 m], on soil, 16 April 1965, Iwatsuki, Sharp & Sharp 10022 (NY); Ranbi forest near Darjeeling [26° 59' N, 88° 16' E], ca. 7400 ft. [2256 m], on soil, 16 April 1965, Iwatsuki, Sharp & Sharp 6656 (NY);
INDIA, SIKKIM: without locality, 7000 ft [2134 m], s.d., Hooker 1238 (BM, NY).
NEPAL: [Sankhuwasabha District], Milke Bhanjang (on south side of Milke Bhanjan on way to Chainpur), [27° 17' N, 87° 19' E], c. 9500 ft. [2896 m], on steep side of path near summit, 04 December 1961, Norkett 8491 (BM); [Dhankuta District] between Hile and Chitre [27° 04' N, 87° 23' E], 1900–2400 m (2150 m), on clay, 05 June 1972, Iwatsuki 223 (NY); between Hile and Chitre, [27° 04' N, 87° 23' E], 1900–2400 m (2150 m), on soil, 05 June 1972, Iwatsuki 226, (NY); Between Dor and Chitre, [27° 04' N, 87° 24' E], 2600–2400 m (2350 m), on soil, 07 July 1972, Iwatsuki 2372 (NY); Rasuwa District, south bank of Langtang Khola above Syabru, 28° 08' N, 85° 23' E, ca. 1720 m, bouldery river bank, on gravel bank, 23 April 1992, Long 22034 (E); [Taplejung District]: Ghunsa Khola between Pheri and Ghunsa, 27° 39' N, 87° 56' E,
59
ca. 3330 m, open Juniperus/ Rhododendron woodland, on soil by stream, 07 September 1989, Long 16699 (E); [Terathum District], between Basantapur (Bilbatay Bhanjyang) and Dor, [27° 08' N, 87° 24' E], 2300–2600m (2350 m), on soil, 06 June 1972, Iwatsuki 333 (NY); between Basantapur (Bilbatay Bhanjyang) and Dor [27° 08' N, 87° 24' E], 2300–2600m (2350 m), on soil, 06 June 1972, Iwatsuki 332 (NY); [Sankhuwasabha District], between Shewaden and Papung, [27° 32' N, 87° 36' E], 2600–2000m (2250 m), on soil, 29 July 1972, Iwatsuki 2027 (NY, H); between Topke Gola and Shewaden [27° 37' N, 87° 35' E], 3600–2600 m (3350 m), on soil, 28 June 1972, Iwatsuki 1836 (NY).
Map 8. Distribution of Oligotrichum falcifolium in the Sino-Himalaya.
60
0.5 mm
0.4 mm 0.5 mm
0.5 mm
0.4 mm
3
0.4 mm 4
5
2 6
50 µm 50 µm 1
7
8 50 µm
60 µm 9 60 µm 10
Figure 8. Oligotrichum falcifolium 1, habit dry; 2, habit wet; 3, Stem leaf in dorsal view; 4, Stem leaf in ventral view; 5, Perichaetial leaf in ventral view; 6, Median cells of leaf lamina; 7,
Leaf margin; 8, Lamella in side view; 9, Basal cells of leaf lamina; 10, Cross-section of leaf. (1–
10 drawn from Hara et al. 20064 (H)). 61
3.2.8. Oligotrichum glaciale C.C. Towns.
J. Bryol. 20: 52, f. 2, 1998. TYPE SPECIMEN: India, Kashmir, Rasbal [34° 25' N, 75° 00' E], ca. 3800 m, at the edge of melting snow below crags above the stream, 09 August 1989, Townsend 89/401 (holotype, E, seen).
Figure 9, Map 9
Stems greyish-green to blackish green, erect, small, (0.5–)0.8(–1.0) cm high, mostly in tufts and without branching. Leaves cucullate and profoundly concave in both dry and moist conditions, oblong; stem leaves 1.6–1.9(–2.4) × 0.7–0.9 mm, obtuse at the apex, not sheathing at the base; margins almost entire or slightly dentate at the apex; costa rather broad, often reaching apex; ventral lamellae confined to the costa, wavy, in 6– 10 rows, 6–9 cells high, dorsal lamellae absent; median leaf cells rounded to quadrate, 20–25 µm wide, slightly thin-walled; basal cells rectangular, 50–60 × 7.5–10(–12.5) µm, slightly thick walled. Perichaetial leaves long, lanceolate, margins almost entire and slightly dentate at the apex with strongly wavy ventral lamellae on costa. Sporophytes rare. Setae reddish brown 20–30 mm, straight. Capsule single, ovoid, 2.8–3.0 × 1.0 mm in size; with a spongy apophysis at the base with numerous cryptopore stomata; peristome teeth 32, single. Opercula with short beak. Spores pale brown, 10–12 µm in diameter.
Distribution in the Region: Pakistan: Baltistan; India: Kashmir, Sikkim; Nepal; China: Yunnan. World distribution: Sino-Himalaya; not yet reported from outside the region. New to Pakistan, Nepal and China.
Ecology: Commonly on steep hill sides, open rocky valleys, on melting snow beds and seepage below glaciers; grows in very high altitudes; alt. 3800–4830m.
Taxonomic Notes: This species was described recently by Townsend in 1998 from two localities in Kashmir, India. In the protologue Townsend commented “In the field the plant resembled a Psilopilum. However, microscopic examination ruled this out, the marginal cells of the leaves showing none of the elongation displayed by the two species of Psilopilum, which are arctic mosses”. The puzzling Oligotrichum specimen mentioned by Bell and Hyvönen (2012) collected by Hedderson (Hedderson 12395, H) from Pakistan has also been identified as Oligotrichum glaciale. Sporophytes of O.glaciale were first discovered in Long’s collection from Sikkim, India (Long
62
22696, E). The sporophyte of O. glaciale (not described in the protologue) has Notologotrichum-like features including a spongy apophysis bearing large cryptopore stomata, but the capsule shape is rather different. (A comparative description of the capsule with some related taxa is given in Chapter 4).
Additional Specimens Observed:
PAKISTAN, BALTISTAN: Deosai National Park, valley of Kala Pani River, near crossing of track from Skardu to Astor, 35° 00' 37” N, 75° 19' 26” E, 4200 m, steep slopes with exposed granite cliffs and occasional meltwater channels, 27 July 1998, Hedderson 12395 (H).
INDIA, KASHMIR: Gangabal, above the west end of the larger lake, [34° 25' N, 74° 55' E],ca. 3700 m, on damp earthy bank in block scree, amid Bergenia stracheyi in seepage below glacier, 12 August 1989, Townsend 89/ 456 (E).
INDIA, SIKKIM: West District, between Thangshing and Lam Pokhari, E side of Prek Chhu valley, 27° 30' N, 88° 11' E, ca. 4105 m, open moorland with dwarf Rhododendron, on peaty bank, 19 July 1992, Long 22696 (E); between Chemathang and Gocha La, 27° 36' N, 88° 11' E, ca. 4830 m, stable moraine ridge, on soil on boulder, 22 July 1992, Long 22811 (E).
NEPAL: Taplejung District, tributary of Simbua Khola on south side of Yalung Glacier, 27° 32' N, 87° 59' E, ca. 4190 m, steep rocky valley, on burnt slope, 20 September 1989, Long 17088 (E); Sankhuwasabha District, Upper Barun Khola valley, tributary valley below Peak 3, above Mera, 27° 48' N, 87° 08' E, ca. 4530 m, open rocky valley, in earthy hollows on bank below cliffs, 02 October 1991, Long 20684-a (E); Makalu Base Camp, 27° 51' N, 87° 05' E, ca. 4690 m, gully at base of moraine; on bank dwarf Rhododendron, 04 October 1991, Long 20949 (E).
CHINA, YUNNAN: Dêqên County, Bai Ma Shan, red sandstone mountain N of mid pass, 28° 22' N, 99° 01' E, ca. 4540 m, steep hillside, on peaty bank amongst dwarf Rhododendron, 07 June 1993, Long 24132 (E).
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Map 9. Distribution map of Oligotrichum glaciale in the Sino-Himalaya
64
2 3 4
0.6 mm 0.6 mm 80 µm
0.05 mm
6 1 5
80 µm 80 µm
50 µm
8 60 µm Figure 9. Oligotrichum glaciale 1, Habit, moist; 2, Stem leaf in ventral view; 3; Stem leaf in dorsal view; 4, Leaf margin; 5, Basal cells of leaf lamina; 6, Lamellae in side view; 7, Median3.2.9 Doubtful cells of leaf and lamina; Excluded 8, Cross Taxa sectionfrom the of Region leaf. (1– 8 drawn from Townsend 89/456 (E)). 65
3.2.9.1 Oligotrichum hercynicum (Hedw.) Lam & DC., Fl. Franc. ed. 3, 2: 492, 1805.
Polytrichum hercynicum Hedw., Sp. Musc. Frond. 94, 1801.
Among the extensive material of Oligotrichum collected from the study area, no O. hercynicum was found, despite literature reports from Asia including “A revision of Polytrichaceae of Hengduan Mountains in China” by Wang & Luo (1994), Smith & Merrill (2007) records it is an arctic-alpine species widespread in northern latitudes. They further mentioned that Oligotrichum hercynicum is a pioneer species, typically forming bright green patches on disturbed soil but, like O. falcatum, also in aquatic habitats. In general appearance this is quite similar to O. aligerum (Mitten, 1864). O. hercynicum was reported from Bhutan by Noguchi (1971) but Smith (1976) showed that this report was based on a specimen of O. semilamellatum. It was also recorded from Xizang (Tibet) by Luo & Wang (2000) but the cited specimen (Wang 8469) belongs to O. crossidioides.
3.2.9.2 Oligotrichum lineatum G.L.Sm. nom. nud.
Oligotrichum lineatum G.L. Sm is an unpublished herbarium name used by Smith for a specimen collected by Iwatsuki and Sharp (Iwatsuki & Sharp 8816, NY) from India (West Bengal; Around Dak Bangalow, Tongloo, Darjeeling area, [27° 06' N, 88° 00' E] ca.10,000 ft [3048m]. This specimen appears to belong to Oligotrichum falcifolium (Griff.) G.L. Sm on account of the number and size of ventral leaf lamellae.
3.2.9.3 Oligotrichum semilamellatum var. yuennanense Broth. ex P.-C. Chen Gen.Musc.Sin. 2:311.1978 nom. nud. This is an invalid name, no Latin Description.
3.2.9.4 Oligotrichum armatum Broth., Symb.Sin. 4: 132, 1929. Type: China , Yunnan [Weixi County], Doyon-lumba am Salwin, 28° 02' N, [2800–3000 m], 24 September 1915, Handel-Mazzetti 8383 (holotype- H-BR, seen).
Study of the type shows this belongs to the genus Pogonatum not Oligotrichum. According to Wang & Luo (1994) it is a synonym of Pogonatum subfuscatum Broth.
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3.2.9.5. Oligotrichum serratomarginatum Lou & Wu, Acta Phytotax. Sin 18: 125. 1980. Type: China. Xizang (Tibet): Basu, 4200m, Chen & Li 76021 (holotype PE, not seen).
According to Wang & Luo (1994) and Wu & Wang (2005) this is a synonym of Pogonatum subfuscatum Broth.
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CHAPTER 04
OBSERVATIONS ON MORPHOLOGY AND TAXONOMIC CHARACTERS
“Do not believe in anything simply because it is found written in your books. Do not believe in anything merely on the authority of your teachers and elders. Do not believe in traditions because they have been handed down for many generations. But after observation and analysis, when you find that anything agrees with reason and is conducive to the good and benefit of one and all, then accept it and live up to it." — Gautama Buddha, Kalama Suththa
4.1 Gametophytic Characters.
4.1.1 Plant Habit
Most Polytrichaceae are unbranched or sparingly branched only by innovations beneath the female inflorescence (perichaetium) (Schofield, 1985, Hyvönen et al, 1998). All Oligotrichum species studied in the Sino-Himalaya are acrocarpous (i.e. producing sporophytes at the tips of main stems (Malcolm & Malcolm, 2006)). In some taxa, like O. aligerum, O. crossidioides and O. falcatum grow as tufts simple to dense branching by innovations was observed. O. nepalense shows branching very rarely beneath the perichaetium but the inadequate material did not allow accurate assessment of this character. Additionally, O. semilamellatum, O. falcifolium and O. glaciale do not show any particular branching by innovations.
Shoot colour cannot be recorded very accurately when studying very old specimens, but clear differences could be indicated from studying more recent collections. The recent collections of O. glaciale demonstrate its characteristic greyish-green or blackish-green colour once moistened.
Plant height varies depending on maturity. Hence, it is difficult to consider as a useful taxonomic character. But, when the type of habitat of the plants is considered, growth form and height of the plants can be quite informative. For example, O. glaciale which grows in very high altitudes (ca. 3500–5000 m), in habitats like snow beds and seepage below glaciers shows very dwarf (less than 1cm) habit. O. nepalense shows
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the same kind of growth form since it also grows in very high altitudes and mountainous regions where the sunlight is a limiting factor.
Overall, plant habit is not a reliable character used to define taxonomic identity, but is a very useful macroscopic character giving some clues to identify the species in the field.
4.1.2 Stem Leaves
As in all mosses, the leaves provide an important source of characters for classification. Leaf orientation, concavity, shape, size, margin and apex are all useful taxonomic characters for identifying Sino-Himalayan Oligotrichum species. In all Oligotrichum species in the Sino-Himalaya leaves are spirally arranged on the stem. The leaf orientation in both wet and dry conditions is an important character to identify species macroscopically. O. falcatum shows deeply cucullate and falcate- secund leaves in both wet and dry conditions which is not shared by any other species in the region. O. glaciale has very broad, profoundly concave leaves (Figure 9) which is a very useful diagnostic character to distinguish it from other species. O. nepalense usually has concave leaves and the leaves are markedly asymmetric. All the other species including O. aligerum, O. crossidioides, O. obtusatum, O. semilamellatum and O. falcifolium have curled twisted or somewhat incurved leaves when dry and erect-patent when moist. Among all the taxa O. semilamellatum has the longest leaves (2.5–4.5 mm) whereas O. glaciale has the shortest leaves (1.6–2.6 mm).
The stem leaves of O. aligerum, O. crossidioides, O. falcifolium and O. semilamellatum, have linear-lanceolate or ovate-lanceolate leaves with acute to acuminate leaf apices. Among all the taxa O. crossidiodes has entire leaf margins without any serrations even at the apex. O. nepalense has remotely serrulate leaf margins and O. falcatum has remotely denticulate leaf margins. Moreover, in O. glaciale the immature leaves have almost entire leaf margins and the fully mature leaves show some serration in the upper 1/3. The mature leaves of O. falcifolium shows subdenticulate leaf margins in the upper 1/3 to 1/2 of the leaf margin. So leaf serration is not a reliable distinguising character and seems to be highly plesiomorphic. Development of leaf margin teeth is sometimes subjected to the prevailing environmental conditions or the genetic makeup (Schofield, 1985, Smith, 1971).
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Smith (1971) mentioned that, the leaf lamina of most Polytrichaceae divided into two portions: a sheathing base, and a diverging, usually a non sheathing base without an alar region or a hinge- tissue. Smith (1971) further mentioned that, “where the leaves are not distinctly sheathing, there is usually a regular and gradual downward transition from quadrate to slightly elongated cells.” This is quite obvious in the leaves of almost all Oligotrichum species studied in the region. Most of the Oligotrichum species observed in the Sino-Himalaya show a slight (but not very clear) sheathing at the base, but some species like O. glaciale and O. nepalense do not show any sheathing at the base.
The nerve or the costa of all species observed is rather broad and reaching at the apex but, in O. semilamellatum, the costa vanishes near the apex. In all species 2/3 of the costa is covered with ventral lamellae.
4.1.3 Leaf Lamellae
The photosynthetic leaf lamellae borne on the ventral (adaxial) surface of the leaf lamina of Oligotrichum (in a few species lamellae are also found on the dorsal (adaxial) surface) significantly increase the number of available taxonomic characters to be studied and hence are very helpful to differentiate species. Number of rows, height (number of cells), and straightness of the lamellae are the most important taxonomic characters used to separate taxa. Almost all Oligotrichum species observed in the Sino- Himalaya had a unistratose leaf lamina with a rather broad costa which harbours the leaf lamellae.
Adaxial lamellae mostly confined to the costa but in some species like O. aligerum and O. crossidioides adaxial lamellae are found on in both costa and leaf lamina. (Figures 2 &3). Adaxial lamellae are usually confined to 1/2– 3/4 of the costa in almost all species studied Many of the species have slightly wavy to highly wavy adaxial lamellae on the costa. O. nepalense is the most distinctive species which has highly dissected, “winged” adaxial lamellae on the costa (Figures 5 & 10)
Abaxial lamellae of O. crossidioides and O. glaciale are also strongly wavy. The height of the abaxial lamellae ranges from 3–18 cells. O. nepalense has the tallest abaxial lamellae (i.e. (8–)10–15 cells) among all the species (Figure 5) followed by O.
70 aligerum. which bears 6–8(–10) cells (Figure 3). O. falcatum has the highest number of rows (i.e. 9–12(–14) rows) of adaxial lamellae (Figure 4), followed by O. crossidioides (i.e. 8–10(–12) rows). The height of lamellae and the number of rows of adaxial lamellae is a useful character to distinguish between O. semilamellatum and O. falcifolium, but O. semilamellatum is a morphologically highly variable taxon and thus solely based on the morphology of the ventral lamellae it is very difficult to get a precise judgement to delimit the two taxa (Figures 7 & 8).
Development of abaxial leaf lamellae is somewhat rare in Oligotrichum species. O. aligerum and O. crossidioides have very clear short lamellae both on the lamina and costa of the abaxial (dorsal) leaf surface (Figures 2, 3, 11 & 12). They are very short (i.e. 1–3(–4) cells high), regularly or irregularly-spaced lamellae. The number and height of dorsal lamellae are more or less the same in both species, but in O. falcatum, O. nepalense, O. obtusatum and O. semilamellatum, there are a few rudimentary abaxial lamellae (teeth or spines) present only near the apex of the leaf lamina. In O. falcifolium and O. glaciale the adaxial leaf surface is totally free of lamellae.
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A. B.
200 µm 20 µm
Figure 10. SEM images of highly dissected adaxial leaf lamellae on the leaf costa of Oligotrichum nepalense A, Leaf surface; B, Lamellae close-up view. (Iwatsuki, 1772 (NY)).
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A
200 µm B
100 µm
Figure 11. SEM images of leaf lamellae on the abaxial surface of Oligotrichum crossidioides A, Leaf abaxial surface; B, Abaxial lamellae close-up view. (Wang 8687, (PE)).
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A
50 µm
B
50 µm
Figure 12. Cross-sections of Oligotrichum species showing the distribution of abaxial and adaxial lamellae A, O. aligerum showing lamellae on both surfaces (Wang & Lou 811918; (PE)). B, O. falcifolium showing lamellae present only on the adaxial surface. (Iwatsuki 226 (NY)).
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The adaxial lamellae are compactly arranged in O. glaciale and O. nepalense which
apparently provides more surface area to capture CO2 for photosynthesis. The correlation between the ecology and the development of the lamellae is interesting (see Chapter 05). One of the important characters associated with the lamina mentioned in literature (Smith, 1971, Ivanova, 2005, Long, 1985) is the modified terminal cells of the margin of leaf lamellae. In some species of Polytrichaceae these cells are different in size and shape from other lamellar cells (Smith, 1971). In many of the species in Oligotrichum the terminal cells are more ore less the same size and shape of the other lamellar cells and it is not a very distinctive character to identify the species. Even though, the protologue of O. glaciale, mentions the terminal lamellar cells are flask-shaped, it is not a very obvious character among individual leaves.
Smith (1971) mentioned that the adaxial lamellae of Polytrichaceae resulted evolutionarily (as they do developmentally) by the division of ventral leaf lamina cells, and that their establishment and subsequent elaboration was favoured because of the photosynthetic efficiency. The adaxial lamellae of the Polytrichaceae dramatically increase the surface area available for the exchange of gasses and water vapour, and efficient use of sunlight thereby increasing the photosynthetic rate and capability of the leaf (Smith, 1971, Bell & Hyvönen , 2012).
4.1.3 Leaf Cells
Leaf lamina cells of Oligotrichum are more or less the same in both branch and stem leaves. The median cells in lamina are rounded, quadrate or irregularly quadrate with thinner cell walls. The shape may vary among the cells in the same leaf this may be due to the mutual pressure exerted by the adjacent cells which is quite an obvious phenomenon in leaf parenchyma cells. Median leaf cells diameter of Oligotrichum in the Sino-Himalaya normally fall in the range (8–)10–18 µm; but O. glaciale is the exception which has comparatively larger median leaf cells which have a diameter of 20–25µm, followed by O. falcifolium which has cells 12.5–17.5µm diameter. Leaf cells of the lamina are unistratose which shows clearly in leaf sections (Figures 2–9). Leaf cells are heteromorphic across the leaf lamina. In cells of leaves with serrate margins, a leaf tooth is always composed of a single cell which is either ovoid or rhomboid in shape.
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The basal cells of leaf lamina are narrow, elongated and rectangular with a range of (15–)20–30(–40) × 8–12.5(–15) µm in size with comparatively thicker cell walls than the median cells. But in contrast, O. glaciale has the longest basal leaf lamina cells among all the Sino-Himalayan taxa with cells 50–60µm followed by O. falcifolium which has a broad length range of 35–60 µm. O. nepalense has the smallest basal cells among all the Sino-Himalayan taxa which is 5(–10) × 2.5–7.5µm.
Hence, cell dimensions of the leaf lamina are quite useful microscopic taxonomic character to key out Oligotrichum species in the Sino-Himalaya.
4.2 Sporophytic Characters
Even though the capsules of O. aligerum, O. falcatum. O. nepalense are not available from the region to make a comparative study, capsule characters of O. semilamellatum and O. falcifolium used to solve the confusion in between them (Figure 13). In most cases O. falcifolium was misidentified as O. semilamellatum by many collectors in the field with the absence of capsules. The observed sporophyte characters of O. semilamellatum and O. falcifolium are listed in Table 2.
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Table 2. Sporophyte characters of O. semilamellatum and O. falcifolium (Most useful characters are highlighted)
Sporophyte Character O. semilamellatum O. falcifolium Seta Reddish brown ; 12–30 cm. Reddish brown; 20–40 cm
Capsule angle Erect to inclined Inclined
Capsule shape Cylindrical Broadly ovoid-cylindrical
Capsule size 3.5–4.0 mm long and 1.8–2.0 2.2 mm long and 1.5 mm in
in diameter diameter
No. of peristome teeth 32, single 32, single
Peristome striations Brown colour striations Brown colour striations
Teeth size 135–140 × 28–32 µm 105–110 × 30–32 µm
Exothecial cells Smooth Smooth
Stomata Phaneropore stomata Phaneropore stomata
Operculum Shortly beaked Very shortly beaked
Spore shape Spherical Spherical
Spore colour Pale yellow to brown Dark brown
Spore size 8–12 µm in diameter 23–25 µm in diameter
Spore ornementation Verrucose Papillose
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100 µm
A
20 µm 1 mm
1 2 3 1 B
2 mm 100 µm
60 µm
4 5 6
Figure 13. Capsule and spore morphologies of O. semilamellatum and O. falcifolium
A. O. semilamellatum 1, Mature capsule with peristome; 2, Peristome teeth; 3, Spores (1–3 drawn from drawn from Long 26271 (E)). B. O. falcifolium 4, Mature capsule with and without peristome; 5, Peristome teeth; 6, Spores (4–6 drawn from drawn from Hara et al. 20064 (H)).
Sporophyte characters such as those of seta and operculum are less useful taxonomic characters to delimit the Sino-Himalayan Oligotrichum species.Opercula of all sporophytes studied are shortly beaked and setae always reddish-brown and in some species like O. crossidioides it is twisted in the distal 1/3 of the length.
One of the most distinguishable characters is the distribution of stomata found in the apophysis (neck or base) of the capsule. Sporophytes collected by Long (Long, 22696,
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(E)) from Sikkim, India provided the first material of O. glaciale sporophytes which were not described previously. The spongy nature of the apophysis (Figure 15 A) and the distribution and nature of stomata (Figure 16 A) demonstrate that this is clearly a unique taxon. In O. glaciale the capsule is ovoid, 2.8–3.0 × 1.0 mm in size, with a spongy apophysis. Stomata are scattered on the apophysis. Stomata are the cryptopore (sunken) type.
Oligotrichum glaciale is the only Sino-Himalayan Oligotrichum species which possesses cryptopore stomata whereas all other Sino-Himalayan taxa have phaneropore (superficial) stomata (Figures 14 & 16).
According to the phylogenetic work done by Bell & Hyvönen (2012,) Hedderson’s puzzling specimen from Pakistan (which is now confirmed as O. glaciale by this taxonomic study) is sister to the African species O. cavalli (Negri) G.L.Sm. Fruiting material of O. cavalli from E (Uganda, Newbould 5285 (E); Kenya, Townsend 85/290 (E)); were studied to confirm this close relationship. Even though the capsule shape is rather different from O. glaciale, O. cavalli capsules possess a spongy apophysis with scattered sunken (cryptopore) stomata at the base of the capsules as in that species.
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1 2
50 µm 50 µm
Figure 14. Cryptopore and phaneropore stomata at the base of Oligotrichum capsules 1, Cryptopore stomata at the base of the capsules of O. glaciale showing the stoma deeply immersed in a crypt formed by overreaching adjacent exothecial cells (drawn from Long 22696 (E)); 2, Phaneropore stomata at the base of the capsules of O. obtusatum showing stomata fully exposed on the surface, with its guard cells on the same level as the adjacent exothecial cells. (Drawn from Iwatsuki 1666 (NY)).
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A.
1 mm
B.
100 µm
Figure 15. SEM images of the sporophyte of Oligotrichum glaciale A, SEM image of the capsule (Long 22696 (E)) B, SEM image of the peristome (Long 22696 (E)).
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A
B
Figure 16. SEM images of stomata in Oligotrichum A, SEM image of the cryptopore stomata at the base of the capsule of O. glaciale (Long 22696 (E)) B, SEM image of the phaneropore stomata at the base of the capsule of O. obtusatum (Iwatsuki 1666, (NY))
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The peristomes of all species of Oligotrichum in the Sino-Himalaya are single, have 32 teeth in the peristome and the teeth have striations. Only a few species (including O. semilamellatum, O. falcifolium and O. obtusatum) showed slightly clear peristome membrane. As Smith (1971) mentioned almost all taxa showed peristome teeth which are single, narrow, pointed and well separated. (Figure 17).
20 µm
Figure 17. SEM image of the peristome of O. obtusatum showing single, narrow, pointed and well separated peristome teeth (Iwatsuki 1666 (NY)).
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Spore characters are also important in distinguishing between taxa. All the spores of Oligotrichum species studied in Sino Himalaya are spherical, pale yellow to dark brown in colour. The average spore diameter falls in the range of 8–12 µm. But O. falcifolium is the exception which has comparatively larger spores with a diameter of 23–25 µm. Spore surfaces of Oligotrichum species in the Sino-Himalaya are either verrucose or papillose.
In conclusion, sporophyte characters are of limited value in delimiting species of Oligotrichum in the Sino-Himalaya with the available material studied.
The following table (Table 3) provides a concise summary of the observations made based on the Oligotrichum species observed.
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Table 3. Morphological characters used to separate the Sino-Himalayan Oligotrichum species using new observations.
Character O. crossidioides O. aligerum O. falcatum O. nepalense Plant height 1.0–1.5 cm 0.5–1.5 cm 1.5–2.0(–5.0) cm 1.5–1.0 cm Branching Plants in tufts, simply Plants in tufts ,sparingly Simple to much branched Simple and rarely branching by innovations. branched by innovations by innovations branching
Leave orientation in Mostly erect when dry and Often crisped when dry Falcate-secund when Falcate-secunded and less dry and wet erect-patent when wet. and erect-patent when both dry and wet. patent when moist conditions wet. Leaf length 2.5– 3.5 mm (2.5–)2.7–3.0(–3.3) mm 1.5– 3.0 mm 1.0(–1.3)mm Leaf width 0.2–0.5 mm 0.3–0.5 mm 0.6–1.0mm 0.5–(–0.6) mm Leaf margin Entire Serrate or serrulate Remotely denticulate or Remotely serrulate almost entire but several larger teeth just below the leaf apex Leaf shape Lanceolate Lanceolate Lanceolate Oblong oval to oblanceolate Leaf apex Obtuse Acute to acuminate Acute Acute Sheathing at base Slightly sheathing Slightly sheathing Slightly sheathing No clearly sheathing Costa Broad, often reaching at apex Broad, often reaching at Broad, often reaching at Broad, often reaching at apex apex apex
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Ventral lamellae On both costa & lamina Restricted to costa Restricted to costa Restricted to costa 1. No. of rows 8–10(–12) 6–8(–10) 9–12 (–14) 6(–10) 2. Height 4–6 (4–)6–10 6-10 (8–)10(–15) 3. Straightness Strongly wavy Linear, regularly spaced Slightly wavy Highly dissected; winged
Rare; on the lamina, lamina Rudimentary, irregularly Dorsal lamellae In both lamina and costa; In both lamina and costa; with low teeth/lamellae spaced, found in both leaf 12-15 rows, 1–2 cells high 2–4 rows, 1–3 cells high near the apex; 1-2 cells lamina and costa;1-2 cells high high Median leaf cells 1. Diameter 8–10 μm (8–)10–15 μm 8–15(–18) μm 2.5–5.0 µm 2. Shape Rounded, quadrate to Rounded to quadrate Quadrate to irregularly Rounded, quadrate to irregularly quadrate quadrate irregularly oval 3. Cell walls Thin-walled Thin-walled Thin-walled Thin-walled Basal cells 1. Length and width 20–30(–32) ×8–12.5μm 25–38(–40) ×10–15μm 15–25(–35) ×10–15 μm 5 (–10) ×2.5–7.5 μm 2. Shape Rectangular Rectangular Rectangular Rectangular 3. Cell walls Slightly thick-walled Slightly thick-walled Thick-walled Slightly thick-walled Setae Straight; reddish-brown, 1.6– Sporophytes not seen Sporophytes not seen Sporophytes not seen 2.1cm,
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Capsule 1. Shape Cylindrical, mostly curved Sporophytes not seen Sporophytes not seen Sporophytes not seen
2. Lid Conic with short beak 3.Peristome 32, single Sporophytes not seen Sporophytes not seen Sporophytes not seen Spores 1. Shape Spherical 2. Diameter 12–15(–16) μm
.
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Table 3. Cont.
Character O. obtusatum O. semilamellatum s.l. O. falcifolium O. glaciale Plant height 0.5–1.5cm 1.0– 2.5(–3.0) cm 0.5–1.5 cm (0.5–)0.8(–1.0) cm Branching Unbranched Unbranched Unbranched Mostly tufts and without innovations Leave orientation in Incurved when dry and erect- Recurved when dry and Curled and incurved Cucullate and profoundly dry and wet patent when wet. erect-patent when wet. when dry and erect concave in both dry and conditions patent to slightly falcate wet conditions when wet. Leaf length 1.4– 1.7 mm 2.5– 4.5 mm 1.8–2.0 (–2.2) mm 1.6– 1.9 (–2.4) mm Leaf width 0.5–0.7 mm 0.5–0.8(–1.0) mm 0.8-1.0 mm 0.7–0.9 mm Leaf margin Serrate Slightly dentate to serrate Sub-denticulate in (Slightly) dentate upper 1/3 to 1/2. Leaf shape Oblong-ovate to oblong- Lanceolate Lanceolate Oblong lanceolate Leaf apex Obtuse Acute to acuminate Acute Obtuse Sheathing at base Slightly sheathing Slightly sheathing Slightly sheathing No clear sheathing Costa Broad, often reaching at apex Vanishing below at apex Broad, often reaching at Broad, often reaching at apex apex Ventral lamellae Restricted to costa Restricted to costa Restricted to costa Restricted to costa 1. No. of rows 3– 8(–10) 4–8(–10) 4-7 6 –10
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2. Height 5–6 4–6 3-5 6–9 cells 3. Straightness Slightly wavy Slightly wavy Slightly wavy Wavy
Dorsal lamellae Absent or with a very few A few rudimentary Absent Absent spines ; irregularly spaced on the lamellae (teeth); 1–2 cells back. Median leaf cells 1. Diameter 10–12(–15) µm 10–12(–15) µm 12.5–17.5 µm 20–25 µm 2. Shape Rounded, quadrate to Rounded, quadrate Rounded to quadrate Rounded to Quadrate. irregularly oval 3. Cell walls Thin-walled Thin-walled Thin-walled. Thin-walled Basal cells 1. Length and width 20–25 × 8–12.5 µm 20–45 ×8–10 µm 35–60 × 7.5–12.5 µm 50–60 ×7.5–10(–12.5) µm 2. Shape Rectangular Rectangular Rectangular Long, rectangular cells 3. Cell walls Slightly thick-walled Slightly thick-walled Slightly thick-walled Slightly thick-walled Setae Straight, reddish brown, Straight, reddish brown, Straight, reddish brown, Straight, reddish brown, 20–30 mm 12–30 mm 20–40 mm 20–30 mm Capsule 1. Shape Oblong-ovoid to shortly Cylindrical. Broadly ovoid- Ovoid cylindrical. Shortly beaked. cylindrical 2. Lid Shortly beaked. Shortly beaked Shortly beaked
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Peristome 32, single 32, single 32, single 32, single
Spores 1. Shape Spherical Spherical Spherical Spherical 2. Diameter 10–12.5 µm µm 8–12 µm 23–25 µm 10–12 µm
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