Mosses and Liverworts of Britain and Ireland: A Field Guide 978-0-9561310-1-0

Table of contents :
Contents
Foreword and Acknowledgements.. iii
Preface.. v
Introduction..1
Liverwort and hornwort gallery..5
Moss gallery..9
Field key to commoner and/or distinctive mosses and liverworts..21
Field key to Sphagnum..61
Calobryales..72
Jungermanniales..73
Metzgeriales..228
Sphaerocarpales..250
Marchantiales..251
Anthocerotales..272
Sphagnales..276
Andreaeales..311
Polytrichales..316
Tetraphidales..333
Buxbaumiales..336
Diphysciales..338
Archidiales..339
Dicranales..340
Pottiales..420
Grimmiales..505
Seligeriales..544
Timmiales..553
Encalyptales..555
Funariales..560
Splachnales..568
Bryales..578
Orthotrichales..641
Hedwigiales..665
Hookeriales..667
Hypnales..670
Habitat lists..825
Index..835

Citation preview

Mosses and Liverworts of Britain and Ireland a field guide Edited by Ian Atherton Sam Bosanquet Mark Lawley Published by British Bryological Society

Contents Foreword and Acknowledgements........................................................................... iii Preface..................................................................................................................... v Introduction............................................................................................................. 1 Liverwort and hornwort gallery................................................................................. 5 Moss gallery............................................................................................................. 9 Field key to commoner and/or distinctive mosses and liverworts............................ 21 Field key to Sphagnum............................................................................................ 61 Liverworts (Marchantiophyta) j Leafy liverworts Calobryales......................................................................................................... 72 Jungermanniales................................................................................................. 73 j Thallose liverworts Metzgeriales..................................................................................................... 228 Sphaerocarpales................................................................................................ 250 Marchantiales................................................................................................... 251 Hornworts (Anthocerotophyta) j Anthocerotales................................................................................................. 272

© British Bryological Society 2010 Registered Charity no. 228851 For information about British Bryological Society Publications please contact the Secretary – see the Society’s website at www.britishbryologicalsociety.org.uk All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without prior permission of the copyright owner. Mosses and Liverworts of Britain and Ireland – a field guide Edited by Ian Atherton, Sam Bosanquet and Mark Lawley First edition published 2010 Printed in the United Kingdom by Latimer Trend & Co. Ltd, Plymouth ISBN 978-0-9561310-1-0 paperback

Front cover photo Golitha Falls, Cornwall. Ian Atherton Spine artwork Orthotrichum affine. Jacqueline Wright

Mosses (Bryophyta) j Sphagna Sphagnales....................................................................................................... 276 j Acrocarps Andreaeales...................................................................................................... 311 Polytrichales...................................................................................................... 316 Tetraphidales.................................................................................................... 333 Buxbaumiales................................................................................................... 336 Diphysciales...................................................................................................... 338 Archidiales........................................................................................................ 339 Dicranales......................................................................................................... 340 Pottiales............................................................................................................ 420 Grimmiales....................................................................................................... 505 Seligeriales........................................................................................................ 544 Timmiales......................................................................................................... 553 Encalyptales...................................................................................................... 555 Funariales......................................................................................................... 560 Splachnales....................................................................................................... 568 Bryales.............................................................................................................. 578 Orthotrichales................................................................................................... 641 Hedwigiales...................................................................................................... 665 Hookeriales...................................................................................................... 667 j Pleurocarps Hypnales.......................................................................................................... 670 Habitat lists........................................................................................................... 825 Index.................................................................................................................... 835

Foreword The want of a field guide to mosses and liverworts has for many years hindered the spread of interest in British field bryology. We hope that naturalists who are already studying mosses and liverworts will find the guide useful, but that it will also reach into the wider community of naturalists, attracting many to bryology for the first time, and in doing so transform a backwater of natural history into an accessible and popular interest. The field guide is published by the British Bryological Society (BBS), rather than by a commercial publisher. This has minimized the costs of production, ensuring the book’s availability to the widest possible readership. Furthermore, the BBS will use all proceeds from sales in order to promote the study of bryophytes. The BBS will continually update the text, maps and illustrations on its website (www.britishbryologicalsociety.org.uk), as alternative and additional material becomes available, and publish new editions of the guide every few years. Please use the feedback facility on the BBS web page for the guide in order to notify any errors or omissions, and suggest additions or changes for future editions of the guide.

Acknowledgements The Editors and the British Bryological Society are indebted to the following people without whose generous contributions and advice this project would not have been possible: Andy Amphlett, Fiona Aungier, John Birks, Irene Bisang, Tim Blackstock, Tom Blockeel, Des Callaghan, Fiona Cameron, Rachel Carter, Paul Davison, Jo Denyer, Sean Edwards, Effy Everiss, the late Bob Finch, Jan-Peter Frahm, David Genney, Martin Godfrey, Robert Goodison, Jonathan Graham, Tomas Hallingbäck, Lars Hedenäs, Alan Hale, Nick Hodgetts, David Holyoak, Cathy Jenks, Larry Jensen, Richard Lansdown, David Long, Niklas Lönnell, Michael Lüth, Iain MacDonald, Bill Malcolm, Nancy Malcolm, Ralph Martin, Rosemary McCance, Oliver Moore, Graham Motley, John O’Reilly, Brian O’Shea, Alan Orange, Jean Paton, Sandy Payne, Sharon Pilkington, Mark Pool, Ron Porley, Chris Preston, Joy Ricketts, Christine Rieser, Gordon Rothero, Karen Rowlett, Fred Rumsey, David Rycroft, Neil Sanderson, Jonathan Sleath, Robin Stevenson, Stewart Taylor, Sue Townsend, David Wagner, Howard Wallis, Mike Walton, Malcolm Watling, Alan Watson, Rosemary Winnall, Dan Wrench and Jacqueline Wright. The distribution maps were very kindly generated and supplied by Stephanie Ames and Chris Preston at the Biological Records Centre, Centre for Ecology and Hydrology, Wallingford, and are based on the records held in the BBS database. We also thank Henry Arnold for providing draft maps at an earlier stage of the project. The Editors would also like to acknowledge the support of Alexandra Atherton, Clare Bosanquet and Jim Lawley throughout this project.

Photo Branches of a tree covered in Hypnum cupressiforme. Ian Atherton

iii

Preface Why study mosses j Because Britain and Ireland have a very rich bryoflora and liverworts?

Most mosses and liverworts thrive in moist conditions, which is why Britain and Ireland have about two-thirds of all European species of bryophytes (mosses and liverworts), compared with only about a sixth of European species of flowering plants and ferns. Indeed, some of our rarer species are globally rare, so we have a particular responsibility for knowing where they occur, elucidating their ecological requirements, and conserving them. Moreover, our commoner bryophytes are important for understanding the natural environment in this country because they are such a prominent part of our vegetation, particularly in wetter, western districts.

j Because you can easily add to what we know about mosses and liverworts Far fewer naturalists study bryophytes than flowering plants and ferns. Consequently, we know less about bryophytes’ geographical distributions, life cycles and other factors which influence the occurrence and frequencies of species, making it much easier for amateur naturalists to contribute to our knowledge and understanding of bryophytes.

j Because you can study them at all times of the year Most bryophytes are visible in all seasons, so they offer round-the-year interest, unlike many flowering plants, which die back out of season. Indeed, it is often easier to find mosses and liverworts in winter, when they are less likely to be obscured by larger plants.

Nomenclature The names of mosses follow Smith (2004), and those of liverworts follow Paton used in this guide (1999) – see p. 3 for details – because most people will probably use these two Floras in conjunction with this guide. These names are shown in large type at the top of each account. Alternative names, including those used in the most recent Census Catalogue (published in 2008) along with any other names that have enjoyed currency in recent years are printed in smaller type on the line below. A few species that have been added to the British and Irish bryoflora since these Floras have been published are mentioned as ‘similar species’ in the accounts of commoner species.

Photo Bryum capillare in fruit. Ian Atherton

v

Introduction What is a Bryophytes (mosses, liverworts and hornworts) are mainly green, flowerless plants bryophyte? which reproduce by means of spores and/or by asexual gemmae or tubers. Mosses The most recent British moss Flora describes 763 species, and these can be divided into: (a) acrocarps (see pp. 276–669), which grow upright, and bear capsules at the tops of their stems. Many acrocarps grow in disturbed habitats and are short-lived. Others grow on bark or rock. (b) pleurocarps (see pp. 670–823), which form wefts or mats that spread horizontally, with capsules arising from the sides of main stems. Most pleurocarps live longer than acrocarps, and occur in less disturbed habitats.

Liverworts Britain has nearly 300 species of liverwort, and these can be divided into: (a) leafy liverworts (see pp. 72–227), with a stem and leaves. (b) thallose liverworts (see pp. 228–270), with no distinct stem and leaves.

Hornworts Hornworts look like thallose liverworts, except for their reproductive structures (see pp. 272–273). Only four species of hornwort occur in Britain, and are often regarded as ‘honorary liverworts’, but they are a separate group of plants.

How to begin j Buy a hand lens and a spray bottle studying mosses Apart from this field guide, you will need a hand lens with a magnification of ×10, and liverworts ×15 or ×20 in order to see the small features of mosses and liverworts in the field. Most opticians sell hand lenses, or you can buy one from the British Bryological Society (www.britishbryologicalsociety.org.uk). Most mosses and liverworts look very different when they shrivel in dry weather. A bottle with a spray nozzle is useful for moistening them. Most chemists stock spray bottles.

j Contact the British Bryological Society The British Bryological Society (BBS) is the hub and nexus of British field bryology. From its website at www.britishbryologicalsociety.org.uk you can find out about past and future meetings of the Society, which mosses and liverworts are known from the district where you live, other bryologists who are active near to you, and how to join the Society. Most naturalists who become interested in mosses and liverworts join the BBS. Through their membership they meet other bryologists and learn from them. Members are also welcome to send small samples of bryophytes they cannot identify to experienced members, who will help them to identify their plants. Please contact your local recorder (listed on the website) if you find a rare species. In addition, members receive the Society’s bulletin Field Bryology three times a year, containing articles about identification, recording, ecology, details of meetings, etc., as well as Journal of Bryology. The electronic files for this field guide are also published on the BBS website. We intend to revise and update these files from time to time, and reprint the guide every few years. In this way, our field guide will remain up-to-date and in print. Photo Leucobryum juniperoideum on an old tree stump covered in Lepidozia reptans. Alexandra Atherton

1

How to use this j Galleries, keys, and habitat lists field guide

Look through the galleries on pp. 5–18 and decide which one most resembles the plant you have found and wish to identify. Turn to the pages indicated, and compare the illustrations and accompanying descriptions on those pages with your plant. Consult the ‘similar species’ passages as well, to see if one of them is your plant. Alternatively, name your plant by using the keys on pp. 21–59 and pp. 61–70. Turn to the pages indicated, and compare illustrations and descriptions with your plant. Remember to check the accounts of plants mentioned under ‘similar species’ as well as any other members of the same genus. Lists of common species that you are likely to find in particular habitats are provided on pp. 825–834. These lists may help you to narrow your search for the name of the plant you are trying to identify.

j Accounts of species and groups of species The illustrations show whole plants, and those parts of plants which are useful for identifying them and which can be seen with a hand lens. Similarly, the descriptions of plants are of their distinguishing features rather than of every part. The sizes of acrocarpous mosses refer to the gametophyte, and not the sporophyte as well. Scale-bar measurements indicate approximate (not exact) sizes. The ‘similar species’ section is very important because the picture galleries and keys include only commoner species. The plant that you are trying to identify may well be one of these ‘similar species’, and not the species to which the gallery or key has directed you. The descriptions of habitat and the distribution maps will help you to decide whether the plant you are trying to identify is likely to occur in the habitat and district where you have found it, and hence whether your identification is correct. Also, you are less likely to have found a rare species than a commoner one. The distribution maps show post-1950 records by 20 × 20 kilometre squares; the grid lines are 100 km apart, and the insets show the Channel Islands and Shetland. The abbreviations ‘s.l.’, ‘s.s.’ and ‘agg.’ after the names of bryophytes stand for sensu lato (in a broad sense), sensu stricto (in a strict sense), and aggregate (a group of very similar species), respectively. ‘spp.’ after a genus stands for species (plural). At the top outside corner of each species account you will notice a Latin name ending in ‘…ales’. This is the name of the order of bryophytes to which that species belongs. This field guide fully illustrates and describes approximately 75 % of British and Irish bryophytes – both common and rare. In addition, there are brief notes about the remaining 25 % of species that cannot be identified without recourse to microscopical features.

It is impossible to identify every bryophyte to the level of species in the field 2

The guide is for use in the field, and only includes features that can be seen with the naked eye or a hand lens. You don’t need any other equipment when you go out to look for bryophytes.

to species by their microscopic features. If you wish to identify every moss and liverwort you find, you will need to use a microscope in order to see such small features, and a Flora in order to identify these species.

j Microscopes A stereo microscope with incident illumination from above and transmitted light from below the stage is best for dissecting leaves, fruiting structures and other parts of plants in order to examine their cellular features using a compound microscope. Dissect your plant in a little water in a transparent Petri dish. Watchmaker forceps with very fine tips are ideal for dissecting mosses and liverworts. You will also need some microscope slides and coverslips for examining parts of plants under a compound microscope. The BBS (see p. 1) offers advice about buying and using microscopes, and also supplies watchmaker forceps. The Society also has two microscopes that are available for loan to beginners.

j Floras A Flora describes details of all species, including all rarities, and the species descriptions and keys use microscopical features as well as field features. The most comprehensive and up-to-date Floras for British and Irish bryophytes are: Paton, J.A. (1999). The Liverwort Flora of the British Isles. Harley Books. ISBN 0 946589 60 7. Smith, A.J.E. (2004). The Moss Flora of Britain and Ireland. 2nd edition. Cambridge University Press. ISBN 0 521 54672 9.

j Collecting mosses and liverworts You will frequently need to collect a small amount of a plant which you cannot identify in the field in order to examine it later microscopically. Collect only a small proportion of the bryophyte – just sufficient for identifying it. Do not collect so much that the plants you leave are unlikely to survive, and never collect all of a population. Collect a few of any shoots or thalli that happen to be fruiting or fertile, because their features will help you identify the plant. The BBS Code of Conduct (which includes recommendations for collecting) can be found at www.britishbryologicalsociety. org.uk Sheets of discarded paper or old newspaper (about 30 × 20 cm) or envelopes are fine for collecting specimens. Fold the paper over at the edges to prevent your plant from falling out, and on the outside write the name of the place where you found it, the grid reference, the habitat (e.g. deciduous woodland, arable field, bank of river), what it was growing on (e.g. trunk of ash tree, clay soil, sandstone boulder) as well as the date. Keep each plant you collect in a separate packet, so that they do not become mixed up. If your plant is very wet, squeeze out as much water as you can before putting it in the packet, because mosses and liverworts keep best when dry. The plant will resume its natural form and appearance when you wet it again for examination at home.

Mark Lawley

Studying mosses and liverworts with a hand lens in the field is very enjoyable. Nevertheless, while many species can be identified in the field, and even more can be identified to the level of a genus, many of them can only be identified accurately

3

Liverwort and hornwort gallery These galleries show a small selection of the commonest bryophytes, and are intended for use by complete beginners who do not yet feel confident using the key.

1. Thallose liverworts

1 cm

j Lunularia (p. 252)

j Pellia (pp. 235–237)

1 cm

1 cm 1 cm

j Marchantia (p. 258)

j Metzgeria (pp. 245–248)

j Conocephalum (p. 255)

j Riccia (pp. 261–270)

1 cm 1 cm

j Anthoceros (p. 272)

j Blasia pusilla (p. 240) 5 mm

1 cm Photo Sporophytes of Aneura pinguis. Sean Edwards

1 cm

j Riccardia (pp. 243–244)

5

2. Finely toothed lateral leaves

4. Lateral leaves having two, three or four lobes shoot from above

j Ptilidium ciliare (p. 204)

j Marsupella (pp. 156–161)

underside of shoot

2 cm

4 mm

2 mm 2 mm

3. Unlobed lateral leaves shoot from above

3 mm

j Lepidozia (pp. 80–81)

underside of shoot

j Leiocolea (pp. 123–128)

j Calypogeia

2 mm

fissa (p. 85)

shoot from above

underside of shoot

3 mm

5 mm

1 cm

j Jungermannia (pp. 143–150) 5 mm

1 cm 1 cm

j Barbilophozia (pp. 111–114)

j Lophocolea bidentata (p. 183)

j Nardia (pp. 151–154) underside of shoot

5 mm

1 cm

j Plagiochila (pp. 192–199)

6

j Mylia (pp. 141–142)

shoot from above 4 mm 5 mm

j Calypogeia arguta (p. 90)

5 mm

j Lophozia ventricosa (p. 116) 7

Moss gallery

5. Lateral leaves divided into two lobes, with the dorsal lobe lying flat across or reflexed from the ventral lobe j Scapania (pp. 168–181)



Typical acrocarps

Typical pleurocarps

1 cm

j Diplophyllum

1 cm

(pp. 166–167)

6. Lateral leaves divided into a larger upper lobe and a smaller lobule underneath

5 mm 1 cm

shoot from above

3 mm

shoot from above

j Frullania (pp. 211–215) underside of shoot

1. Sphagnum

2. Leaves thick and glossy

shoot from above

j Porella (pp. 206–210)

j Radula (pp. 202–203)

underside of shoot

underside of shoot

j Polytrichastrum/ Polytrichum (pp. 318–326)

2 mm

1 mm

j Pogonatum (pp. 316–317)

3 mm 2 cm

7. Miscellaneous

j Fossombronia (pp. 228–233)

5 cm 1 cm

2 mm

8

j Sphagnum (pp. 276–310)

j Aloina (pp. 471–473)

5 mm

9

3. Leaves arranged in two opposite rows on the stem (cf leafy liverworts, pp. 6–8) j Neckera (pp. 680–682)

j Polytrichum piliferum (p. 324)

j Plagiothecium (pp. 779–785)

1 cm

j Bryum capillare (p. 586)

1 cm

5 mm

1 cm

j Orthotrichum diaphanum (p. 654) 1 cm

j Hedwigia (pp. 665–666)

5 mm

j Fissidens (pp. 404–417) 1 cm

j Homalia trichomanoides (p. 683)

j Racomitrium heterostichum (p. 537)

2 mm

5 mm

5. Leaves without a nerve, or nerve short and difficult to see with a hand lens

j Pseudotaxiphyllum elegans (p. 788) 1 cm

j Fontinalis (pp. 670–671)

1 cm

4. Leaves with colourless tips, or nerve excurrent as a hair j Tortula muralis (p. 479) 1 cm

j Hookeria lucens (p. 667)

j Syntrichia (pp. 494–501)

j Hypnum (pp. 802–810) 5 mm

1 cm

1 cm

1 cm

5 mm

j Grimmia pulvinata (p. 526) 1 cm

10

j Campylopus introflexus (p. 400)

j Andreaea (pp. 311–315) 1 cm

j Pleurozium schreberi (p. 815)

11

6. Leaves with long, fine tips not distinct from the main body of the leaf j Dicranella (pp. 366–371)

8. Acrocarps with leaves that have a translucent blade j Tortula truncata (p. 482)

j Dicranum (pp. 377–387)

1 cm 1 cm

1 cm 1 cm

j Campylopus pyriformis (p. 394)

1 cm

j Bryum capillare (p. 586)

5 mm

j Leptobryum pyriforme (p. 576)

1 cm

j Funaria hygrometrica (p. 561)

7. Acrocarps with leaves that are opaque and lack long, finely drawn out tips j Orthodontium (p. 580)

j Didymodon (pp. 456–466)

9. Mosses with leaves that have a translucent border

j Mnium (pp. 612–614) 1 cm

j Barbula (pp. 454–455)

1 cm

5 mm

1 cm

5 mm

j Atrichum (pp. 329–332)

j Orthotrichum (pp. 646–657)

1 cm 1 cm

1 cm 1 cm

1 cm

12

j Ceratodon purpureus (p. 354)

j Encalypta streptocarpa (p. 557)

j Rhizomnium (pp. 616–617)

j Plagiomnium (pp. 618–623)

13

10. Pleurocarps with straight, nerved leaves

13. Pleurocarps with straight leaves that lack a nerve j Rhytidiadelphus (pp. 816–819)

j Kindbergia praelonga (p. 767)

j Rhynchostegiella (pp. 771–773)

j Rhynchostegium (pp. 760–763)

5 mm

1 cm

j Eurhynchium (pp. 764–766) 1 cm

5 mm

j Brachythecium (pp. 741–752)

5 cm

j Campylium (pp. 709–710)

1 cm

14. Capsules held erect, and clear of leaves on visible seta j Tortula (pp. 475–484)

j Homalothecium (pp. 738–739)

1 cm

1 cm

j Ceratodon purpureus (p. 354)

j Didymodon (pp. 456–466)

1 cm 5 mm

11. Pleurocarps with curved, nerved leaves j Cratoneuron filicinum (p. 701)

j Drepanocladus (pp. 713–714)

1 cm

j Weissia (pp. 421–427) 5 mm

j Dicranoweisia (pp. 364–365)

1 cm 1 cm

1 cm

5 mm

j Scorpidium (pp. 721–723)

12. Pleurocarps with curved leaves that lack a nerve

1 cm

j Ulota (pp. 658–664)

1 cm

j Ctenidium molluscum (p. 812) j Hypnum (pp. 802–810)

j Hypnum (pp. 802–810)

14

5 mm

1 cm

1 cm

j Racomitrium (pp. 533–540)

15

15. Capsules held clear of leaves, and inclined to one side

17. Capsules between the leaves (seta very short, and hidden) j Cryphaea heteromalla (p. 672)

j Brachythecium (pp. 741–752)

j Ephemerum (pp. 503–504)

j Dicranella (pp. 366–371)

5 mm

1 cm

1 mm

j Rhynchostegiella (pp. 771–773)

1 cm 1 cm

j Phascum cuspidatum (p. 486)

j Amblystegium (pp. 702–705)

j Schistidium (pp. 506–518)

j Rhynchostegium (pp. 760–763)

5 mm

j Orthotrichum (pp. 646–657)

5 mm

1 mm

1 cm 5 mm

j Eurhynchium (pp. 764–766)

18. Mosses with a bushy or tree-like habit 1 cm

j Isothecium (pp. 735–737)

j Climacium dendroides (p. 674)

16. Capsules held clear of leaves, and pendulous

1 cm

j Bryum (pp. 581–599)

1 cm

1 cm 1 cm

16

j Campylopus (pp. 391–402)

1 cm

j Thamnobryum alopecurum (p. 684)

17

19. Pleurocarps with blunt leaf tips 1 cm

j Calliergonella (pp. 797–798) j Pleurozium schreberi (p. 815)

1 cm

j Pseudoscleropodium purum (p. 753)

1 cm

20. Mosses with bipinnate or multi-pinnate branches j Hylocomium splendens (p. 821) j Thuidium (pp. 696–697)

1 cm

1 cm

21. Miscellaneous mosses j Tetraphis pellucida (p. 333)

j Andreaea (pp. 311–315)

5 mm 5 mm

j Aulacomnium androgynum (p. 627) 18

1 cm

Gallery drawings Sharon Pilkington, Sean Edwards, Jonathan Graham & Jacqueline Wright Photo Racomitrium ericoides on spoil from a disused slate quarry near Llangollen. Ian Atherton

19

Field key to commoner and/or distinctive mosses and liverworts This key will not provide you with infallible identifications of every moss and liverwort you find. There are three reasons for this:

j the key does not include every species (and indeed, neither does the main body of the field guide). The key covers almost all of those likely to be encountered during your first year or so of bryology, plus a few distinctive but uncommon species;

j the key does not include every form of each species (sometimes a form with curved leaves is diagnostic of a species, but other forms with straight leaves are unidentifiable without a microscope);

j many bryophytes can only be confidently identified to species level by examining microscopic features, and for these species you will have to also refer to a moss Flora or a liverwort Flora (see p. 3). You must also carefully read the account of the species that you think you have keyed to (as well as those of ‘similar species’) before deciding whether you have correctly identified the bryophyte you have found.

j Note on using the key Choose which of the paired sentences best fits your specimen and follow the number at the end of the line to the next pair. Drawings to illustrate some of the sentences are provided, with the labels (a) and (b) indicating the first and second options, respectively. The small numbers in parentheses underneath the main numbers are provided to assist you in going back through the key.

j Dissecting mosses in the field Some features of mosses that the field key refers to are difficult to see on intact shoots; for example, the relative width of the nerve at the base of the leaf, or the colour and extent of any specialized cells in the basal angles of the leaf; you may also need to measure the size of a leaf. In Sphagnum, too, you will need to determine the difference between the spreading and hanging branches and the shape, relative size and orientation of stem leaves, all of which may be difficult with an intact shoot. In these circumstances you may wish to dissect your specimen. You do not need special equipment for this; just use your fingers and thumbs.

j Removing moss leaves for examination Choose a typical shoot and with its tip towards you and the base pointing away from you, hold it against the tip joint of your index finger with your thumb. Using the corner of the nail of your other thumb, scrape down the stem away from you. This usually strips some leaves from the stem. Transfer these leaves to the scale in the margin of one of the following pages, and examine and measure them using your hand lens.

j Sporophyte This key uses vegetative features as much as possible, but many mosses are most readily identified by characters of their capsules and setae. In some cases, such as Ditrichum heteromallum vs. Dicranella heteromalla or Orthotrichum anomalum vs. O. cupulatum, identification is only possible with fertile material. Non-fertile plants may therefore have to remain unidentified. Photo Thuidium tamariscinum and Nowellia curvifolia. David Long

21

1 – 8

Key to Groups 1

2a – 2-lobed leaf



j Plant with distinct leaves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2

j Leaves arranged either strictly in 2 ranks or in 3 ranks (one on each side of the stem and one in mid-ventral line); the leaves most commonly round or 2-lobed, without nerves (sometimes leaves are so deeply divided as to appear 4- or 5-ranked) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . j Leafy liverworts (24, p. 24)

(1)



3a

9a

9b

9 (8)



2a – Leaves in 2 ranks 2b

j Plant without distinct leaves . . . . . . . . . . . . . . . . . . . . . . . . j Thallose liverworts (5, p. 22) & j Hornworts

9 – 19

3 (2)

4a

j Leaves not arranged strictly in ranks (except in Fissidens and Distichium, which have nerved leaves, and Schistostega, which has a shining green protonema); the leaves never 2-lobed, most often tapering to an acute or rounded tip, with or without nerves . . . . . . . . . . . . . . . 3

10a

j Thalli always 1 cm wide; plant strongly scented; pores on upper surface easily visible to naked eye; scales on lower surface not overlapping each other . . . . . . . . . . . . . . . . . . . . . . Conocephalum spp. (p. 255)

12a

12 j Upper surface of thallus with round-topped cells and a spongy appearance; on wet mud . . . . . . . . . . . . . . . . . . . . . . . Riccia cavernosa (p. 263)

(11)



13a

j Plants deep or vivid green; habit various . . . . . . . . . . . . . . . . . . . . . . . . . . 15

j Upper surface of thallus with flat-topped cells, or some roundtopped cells, not appearing spongy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

13 j Thallus narrow, forming mats of Y-shaped plants; either floating or on periodically flooded mud . . . . . . . . . . . . . . . . . . . . Riccia fluitans (p. 261)

(12)

4

0

(3)

5 10



15

4b 20 mm





6

j Gemmae visible in open-topped receptacles; no gemmae on thallus tips; upper surface of thallus with raised pores . . . . . . . . . . . . . . . . . . . . 7

14 j V-shaped groove in upper surface of thallus; thallus edges curved (13) up; clear margin of long, narrow cells along sides of thallus (hand lens) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Riccia sorocarpa (p. 266)

14b

0

j Wide, shallow groove in upper surface of thallus; thallus edges curved down; no clear margin along sides of thallus (hand lens) . . Riccia glauca (p. 267)

10 15 20 mm

15 j Thallus 9 cm tall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Polytrichastrum formosum (p. 320)

31

105 – 115

96 – 104

Acrocarps with shoots like miniature ferns

105a

105 j Leaves very long, narrow and sword-shaped . . . . . . . . . . . . . . . . . . . . . . 106

105b

(104) j Leaves relatively shorter – roughly triangular or tongue-shaped . . . . . . . . 108 96 j Leaves nerveless; protonema shining green like glow-worm (80) tails; scarce plant of caves, rabbit holes, etc. . . . . . Schistostega pennata (p. 419) 96a



106 j Plants dark, blackish-green; leaves 6–9 mm long, with long, untidy-looking hair point . . . . . . . . . . . . . . . . . . Campylopus atrovirens (p. 398)

j Leaves nerved to tip or near it; protonema not shining . . . . . . . . . . . . . . . 97

(105)

97 j Minute (shoots 5 pairs of leaves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

(106)



j Hair points not bent back when dry; nerve 5 times length of capsule) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Racomitrium heterostichum agg. (p. 537)

117 j Capsules always present (search carefully for old ones) on short (114) seta so capsule base is hidden among sheathing leaves . . . . . . . . . . . . . . . . 118

118a

126 j Robust, 2.5–15 cm tall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 (86) j Small, up to 2 cm tall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 127a

127 j Leaves strongly curved and turned to one side, at least at the shoot tip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

(126)

j Capsules (if present) on seta long enough to hold capsule base clear of leaves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119



128 j Leaves very long (the longest being 10–14 mm), all sickleshaped and very strongly turned to one side of shoot; chiefly in sheltered, humid woods . . . . . . . . . . . . . . . . . . . . . . . . Dicranum majus (p. 379)

118 j Plants squat and unbranched; old capsules with folds when dry; young capsules with slightly hairy calyptra . . . . Orthotrichum diaphanum (p. 654)

(127)

(117)

119a

119b

j Plants loosely branched; old capsules smooth; calyptra without hairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Schistidium crassipilum (p. 511)

119 j Leaves abruptly narrowing into hair point (may be parallel-sided (117) or tapering before abrupt narrowing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

129a

129 j Nerve at base of leaf 1/3 to 1/2 width of base of leaf (hand lens); plants dark green; leaves wavy when dry, 4–5 mm long . Campylopus flexuosus (p. 395)

j Leaves gradually tapering into hair point . . . . . . . . . . . . . . . . . . . . . . . . . 123

(128)



5

(119) j Hair point with sharp teeth throughout its length (hand lens) . . . . . . . . . 122

0 5

130 j Forming deep cushions or scattered in bogs and wet places on (127) moors; leaves dull, yellowish-green, spreading when moist, shrivelled and curled when dry . . . . . . . . . . . . . . . . . . . . . . Aulacomnium palustre (p. 625)

121 j Leaves tongue-shaped, appearing thickened on margins (hand (120) lens); capsules on long (>1.5 cm) straight seta . . . . . . . . . Tortula muralis (p. 479)

15

121b

j Leaves gradually tapering from base, then abruptly narrowing into hair point; margins recurved, but not thickened; capsules on short (