Vagrant Epiphytic Mosses in England and Wales

Article

o the non-bryologist, bryophytes seem remarkably static compared Vagrant with birds, butterflies or moths. Bryologists know that distributions of species change, and that losses of epiphytic Tspecies to habitat destruction or pollution are countered by increasing taxa and spreaders (e.g. Jones, 1991), although it is often possible to mosses in revisit a historic locality for a moss or liverwort and find it in just the same place where our forefathers noted it decades before. Acidophiles England were increasing when E.W. Jones looked at Oxfordshire’s changing flora, but changing pollution and climate have led to a subsequent shift and Wales from acid substrates to more base-rich, but also often very nutrient-rich, conditions (Bates & Preston, 2011). Changing conditions are exploited particularly rapidly by epiphytes, which have evolved effect- Sam Bosanquet ive dispersal mechanisms to cope with sudden host death and to allow colonization of bark examines some with suitable pH and nutrient status, which may of the reasons not be present nearby. It seems highly likely that epiphytes have been appearing as casual, non- why certain persistent colonies for many years, and that some regionally extinct species or current conservation epiphytic species priorities may be no more than occasional colon- are spreading into ists. Some bryophytes are already being found in significant quantity outside the range in which England and Wales they occurred in the early 20th century, for exam- and becoming ple the liverworts Cololejeunea minutissima and Colura calyptrifolia, and the moss Ulota phyllantha established. In (Bates & Preston, 2011). They are effectively addition, he lists a internal spreaders, expanding from ecologically suitable ground within the British Isles. This arti- number of potential cle covers species that appear to be arriving in England and Wales from outside these two coun- ‘spreaders’ that we tries, and summarizes records of vagrant epiphytic should all keep our mosses as well as discussing their likely origins. Spores arriving from outside England and

Ian Atherton eyes open for Wales may establish relatively persistent colonies,

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as with Orthotrichum obtusifolium on a street tree Pluijm, 2004). Some Dutch bryologists have collection in 1855 (www.verspreidingsatlas.nl), in Cardiganshire or in a Cambridgeshire orchard, been focussing on epiphyte recording for the and the single British record of Neckera pennata, or may form single tufts that do not spread, as last 20 years. It is quite clear from recent British whilst the liverwort Ptilidium pulcherrimum has is the case for Antitrichia curtipendula at Bristol records that vagrant Orthotrichum species turn up long been considered a regular casual in eastern Zoo or in another Cambridgeshire orchard, or in areas where active recorders are concentrating Britain originating from Scandinavia. Britain’s only known Orthotrichum acuminatum. on seeking epiphytes, rather than areas closest There are five keys to finding vagrant epiphytes: The exact distinction between a casual colony to Mediterranean Europe – it is hard to explain (1) familiarity with the common British species; and a persistent one – and potentially between otherwise why Bedfordshire, Cambridgeshire, (2) familiarity with non-British species abroad; a species deserving conservation efforts and one Derbyshire, Co. Durham, Norfolk and Suffolk (3) having a search image in your head; (4) that is less deserving – is arbitrary, but the 10 should be the prime epiphyte counties, rather persistence; and (5) a lot of luck. One has to check year cut-off proposed for persisting introductions than Kent, Sussex, Hampshire and Dorset. It a great many trees before finding a rarity, but this (Blockeel, 2010) could perhaps be used. appears that the same may have been true in the process can produce useful lists of common and An illustration of the extent to which epiphytes past, with most historic records of O. consimile, less common species on different host trees and have spread during the last few years in England O. pumilum and O. obtusifolium coming from also aids that all important familiarity with the and Wales is given by the BBS epiphyte survey in areas worked by bryologists such as H.H. Knight, extraordinarily variable Orthotrichum affine and the mid-1990s (Bates et al., 1997). No rare epi- H.N. Dixon and W. Mitten. the other, slightly more consistent Orthotrichum phytes were recorded during the survey, despite Two saxicolous species of Grimmia can also species. competent bryologists recording epiphytes in 107 be considered as vagrants to Britain. G. crinita Most epiphytes that arrive for the first time tetrads between Devon/Glamorgan and Norfolk/ was recorded from Hatton, Warwickshire (v.-c. in Britain probably do so as spores or gemmae Suffolk. The counties making up this transect 38) in the 1870s and 1880s and from Treviscoe, that have come from far away, although the of Britain have produced records of at least six n The author searching for epiphytes. Ian Atherton West Cornwall (v.-c. 1) for a few years from slow eastward spread of the non-fertile, non- vagrants from continental Europe since 2000, 1999. As discussed by Greven (2011), this gemmiferous Microlejeunea ulicina suggests that as have Derbyshire, Yorkshire and Co. Durham suggested that acidified bark can take a long time species seems to arrive in northern Europe from some species probably spread as fragments. A few to the north, all found during general recording to lose its acidity, so recently planted trees often the Mediterranean, grow for a few years and then Mediterranean mosses get a helping hand from rather than a targeted survey. At the same time, provide the best conditions for epiphytes such as die out. A patch of G. tergestina was noted on a man – Fred Rumsey (in litt.) has seen abundant Orthotrichum lyellii, O. pulchellum, O. stramineum Orthotrichum species. breeze-block wall on Fetlar, Shetland (v.-c. 112) Syntrichia pagorum on an old olive tree in his local and O. striatum have become frequent in south The British are somewhat behind the game by SDSB and Dave Genney during the 2008 garden centre – but it seems unlikely that many, if Wales in contrast to their near, or complete, when it comes to locating vagrant epiphytes BBS summer meeting. Records of G. tergestina any, colonies of rare mosses in Britain arise from absence during the survey. It certainly appears as compared with the Dutch, although our more from further south in Britain seem likely to propagules originating from plants on an imported though conditions in Britain in the 1990s were north-western location goes some way to represent the northern edge of an expanding tree. The sole British record of Orthotrichum not suitable for spreading epiphytes, other than explaining the relative paucity of British records European population, coupled with a relict shawii, from Kilkerran Castle in Ayrshire, might acidophilous species. Past pollution may have of southern species. The BLWG Verspreidingsatlas population in Mull and the adjacent mainland, have resulted from importation with the non- left a ‘clean slate’ for colonization, which has Mossen online (www.verspreidingsatlas.nl) is an but the Shetland record is on an artificial native Fraxinus ornus on which it grew, although been coupled with planting of new amenity trees extremely useful internet resource, presenting substrate so far north of the species’ range that trees are usually imported as seedlings or saplings with base-rich bark in nutrient-rich suburban maps, photographs and text (in Dutch) that help establishment on Shetland seems implausible. and importation thus seems rather far-fetched. habitats to provide excellent conditions for new to put British records into context. Almost all of Fetlar is a well-known site for rare birds and is Chance clearly plays a significant role in epiphyte colonists. (Re)-colonization has been shown to the epiphytic vagrants to England and Wales have clearly well situated for attracting vagrants. Other spread, although it remains unknown whether be relatively haphazard in both bryophytes and been noted as spreading into The Netherlands species that may have been spore casuals include southern European Orthotrichum spores are lichens, with some supposedly very sensitive since the 1990s, and there are several additional the single British record of Trematodon ambiguus, common in British airspace and only germinate taxa appearing in areas that were formerly highly Orthotrichum species that we might expect to as this species is increasing in the Netherlands, when they a find suitable niche, or whether such polluted (e.g. Richardson, 1992). It has also been appear in Britain in the near future (van der with 21 records since 1992 following a single spores are themselves rare.

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Species Britain, where sporophytes are rare, whilst most x Orthotrichum acuminatum was discovered and the fourth on an ash trunk in woodland at All information on records comes from the BBS of the remainder may have been vagrants rather new to Britain by Tom Blockeel in the Erewash Flat Isley, Buckinghamshire (v.-c. 24) in 2010. Database housed by the Biological Records than remnant native populations and only the Valley south of Ironville in Derbyshire (v.-c. 57) This pattern seems to reflect the distribution Centre and accessed through the NBN Gateway one at Dungeness remains extant so far as is in December 2004 and persisted there for just of bryologists who are keen on Orthotrichum, (www.searchnbn.net). known. Loose, glossy patches of Antitrichia are 3 years: a relatively rapid death reminiscent of rather than the most likely pattern of arrival reasonably distinctive, but could easily be passed vagrant Grimmia crinita (Greven, 2011). This from Europe, especially given the lack of Nordic x Antitrichia curtipendula declined dramatically over as a scrappy Brachythecium, so odd-looking close relative of O. striatum was overlooked records. Surprisingly, there have only been seven in Britain during the 19th and 20th centuries pleurocarpous epiphytes need to be checked. in the Mediterranean until recently, but is records of this species from The Netherlands and its population is now largely restricted to now known to be widespread and reasonably (www.verspreidingsatlas.nl). O. consimile has upland areas of western Britain from Devon and x Cynodontium sp. was reported from a pear tree common there. There have been records from exserted capsules and flexuose leaves when dry, Cornwall to Cumbria, with a relatively large at Walsoken, West Norfolk (v.-c. 28) by Robin 19 sites in The Netherlands in the last 20 years like O. pulchellum, and differs in having 8 off- proportion of sites in Scotland. Only one colony Stevenson (Hill, 2006). There are five recent (www.verspreidingsatlas.nl), suggesting that it is white exostome teeth rather than the 16 red remains in south Wales, on upland sandstone, Dutch records of Cynodontium polycarpon and highly likely that further tufts will be found in exostome teeth of its commoner relative. Perhaps and many of the colonies in north Wales are one of C. strumiferum from trees with acidified Britain. As its name suggests, O. acuminatum unexpectedly, epiphytic O. anomalum is a on rock, whilst those in south-west England are bark, but no other members of the genus have has acuminate leaves, but so too does O. striatum significant confusion problem, not least because mostly on tors. In contrast, it is locally abundant been recorded from The Netherlands (www. and the key character lies in the peristome: O. epiphytic plants of this saxicolous species are in parts of continental Europe, for example verspreidingsatlas.nl). acuminatum has almost no exostome teeth, often atypically small. the Pyrenees (R.V. Lansdown, pers. comm.), whereas the exostome teeth of O. striatum forming deep cushions on tree branches. It is x Daltonia splachnoides was recorded new to are long and beautifully curled back from the x Orthotrichum obtusifolium was widespread likely that this was the case in Britain before Wales from a conifer plantation in Carmarthen- mouth. British bryologists need to get into the but uncommon in the English Midlands until industrial pollution, although herbarium shire (v.-c. 44), and has not yet been found in habit of checking the peristome teeth of all O. the early 20th century, with records from 20 specimens suggest that much English Antitrichia England. Traditionally, it has been considered an ‘striatum’ that they find. , Orthotrichum consimile. Michael Lüth grew on rocks or walls in the 18th and 19th extremely rare moss of humid areas of western centuries. The only recent records from England Ireland and western Scotland, but recent records x Orthotrichum consimile away from the far south-west and north-west are indicate that it is spreading in Irish conifer first occurred in Britain in from a wood near Holcombe, North Somerset plantations in a similar way to Colura calyptrifolia the Hurstpierpoint area of (v.-c. 6) in 1969; Ditchling and Heyshott, West (Bosanquet et al., 2010). The Welsh colony, West Sussex (v.-c. 13). An Sussex (v.-c. 13) in 1961 & 1968; Prunus spinosa comprising a single, fruiting tuft and one or two extensive revision of speci- scrub at Dungeness, East Kent (v.-c. 15) from non-fertile scraps, clearly originated from a spore mens of O. pulchellum by 1968 to 2000 at least; Malus in a commercial that travelled eastwards from Ireland. Ron Porley revealed no more orchard near Wisbech, Cambridgeshire (v.- recent occurrences, so Tom c. 29) in 2006; Pauwlonia at Bristol Zoo, East x Hypnum cupressiforme var. hesseleri was Blockeel’s discovery of O. Gloucestershire (v.-c. 33) in 2010; a horizontal added to the British list when it was collected consimile on elder at Ashover, ash branch in a hedge at Ashorne, Warwickshire from an apple tree in the Royal Orchards at Derbyshire (v.-c. 57) was the (v.-c. 38) in 1969; and an elder by the River Flitcham, West Norfolk (v.-c. 28) and has first modern record. The Went at Kirk Smeaton, West Yorkshire (v.- subsequently been recorded in another orchard second came from Sledmere c. 63). The Cambridgeshire, Gloucestershire in Cambridgeshire (v.-c. 29). This distinctive Park, South-east Yorkshire and West Yorkshire patches, at least, are clearly pleurocarp, with imbricate, nerveless leaves has (v.-c. 61) in 2008, the third recent colonists, and seem more likely to be a range centred on western Germany, eastern from Crowle Moor, on the spore vagrants from continental Europe than France and The Netherlands, and is considered Thorne Moors, South-west scraps somehow transported from north-western to be a recently evolved taxon. Yorkshire (v.-c. 63) in 2009,

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apart from a single record of a casual tuft on was the most popular host tree (Atlas), and SO2 (v.-c. 27), Northamptonshire (v.-c. 32) and Scotland, but it not particularly common, and elder in West Norfolk (v.-c. 28) in 1989. Recent pollution probably rendered England unsuitable North-east Yorkshire (v.-c. 62) – have the feel also grows on Sarsen Stones at a few sites in records have been: on willow in carr, Gunpowder for O. obtusifolium by the 1900s. British plants of of casual colonies rather than lost natives. There southern England. It is a frequent epiphyte in Park, Waltham Abbey, South Essex (v.-c. 18) O. obtusifolium are often extremely small, and have been two recent southern British records, much of Europe, and was found on apple at The in 2006; in Warboys Wood, Huntingdonshire might be confused with a Zygodon when dry, on an ash trunk at Kensall Quarry, Hertfordshire Royal Orchards, Flitcham, West Norfolk (v.-c. (v.-c. 31) in 2011; on apple in an orchard at but the acute leaf apex of all Zygodon except (v.-c. 20 in 2010, on an ash trunk at Abergavenny 28) in 2005. There is also a record from Spurn, Elm, Cambridgeshire (v.-c. 29) in 2007; on for Z. conoideus var. lingulatus provides a quick in Monmouthshire (v.-c. 35) in 2011, and one South-east Yorkshire (v.-c. 62), a prime site for ash by the Severn, north of Gloucester, West distinction. from northern England on ash by the River vagrant birds, in 1968, and an extraordinary Gloucestershire (v.-c. 34) in 2011; and on a Wear near Low Harperley, Co. Durham (v.-c. one from a churchyard wall top in Paddington street tree maple in Aberystwyth, Cardiganshire x Orthotrichum pallens is rather an anonymous 66) in 2000. Many authors split O. pumilum Green, Middlesex (v.-c. 21) in 2004. All three (v.-c. 46) in 2008. This species is remarkably species and is easy to overlook, so the paucity into two European species: the slightly taller, of these colonies seem likely to have originated common as an epiphyte on street trees in parts of British records may in part reflect confusion more northern/montane O. pumilum s.s. and from the continent, rather than from British of north-eastern France (SDSB, pers. obs.), and over its identification. It has a short, hairless, the extremely squat, lowland Mediterranean colonies, although it is impossible to be sure. www.verspreidingsatlas.nl shows 94 records pale calyptra with an orange tip and perhaps O. schimperi. Dixon (1924) reports the historic This species has a very hairy calyptra and its eight from The Netherlands, mostly from the south. most closely resembles a small O. stramineum, British records as O. schimperi, and both of the exostome teeth are upright when dry. The concentration of historic records in the although it would be simple to dismiss a tuft recent southern records are of that taxon. The English Midlands is peculiar, and may reflect as an odd form of O. affine or O. tenellum. five east Scottish and Co. Durham records are x Orthotrichum shawii has only been recorded the activities of a small number of bryologists, All five historic English records come from more likely to be O. pumilum s.s. given its range from one British site, Kilkerran Castle in Ayrshire for example J.E. Bagnall (8 sites), H.N. Dixon the north of the country, and there are recent in Scandinavia, but more work is needed on this (v.-c. 75) in 1860. This colony may have been the (8 sites) and H.H. Knight (4 sites), who knew records from Addingham, Wharfedale, Mid- species pair in Britain. result of a vagrant spore, but as it was recorded west Yorkshire (v.-c. 62) in 2005, and from on the non-native Fraxinus ornus it could con- , Orthotrichum obtusifolium. Andy Amphlett Weardale, Co. Durham (v.-c. 66) from 1999 , Orthotrichum pumilum. Graham Motley ceivably have been an importation. There seems onwards, and O. pallens is clearly well established a reasonable chance in Weardale (Hodgetts, 2003). It is hard to tell that O. shawii could whether some other historic records were of reappear in Britain, per- casual plants derived from Scandinavian spores. haps in upland areas The only southern British records were made of England because by Chris Tipper on willow at Cassiobury Park, of its predominantly Watford, Hertfordshire (v.-c. 20) in 2007, and upland distribution by Sam Bosanquet on field maple in a hedge in southern Europe. near Dingestow, Monmouthshire (v.-c. 35) There are recent rec- in 2011, both of which are likely to have been ords from two sites vagrants. in The Netherlands. It looks rather like x Orthotrichum pumilum is the most diminutive O. striatum, with a British Orthotrichum, and looks much more more or less smooth squat than O. tenellum, with short, hairless capsule and recurved calyptrae that only partly cover the capsules, exostome teeth, but rather than the long, slightly hairy calyptrae of its endostome is rudi-

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hectads, but then disappeared, and was only how to find what were very scattered, if well O. tenellum. Three historic records from England x Orthotrichum rupestre is widespread on rocks known from Scotland at the time of the Atlas established, colonies of O. obtusifolium. Ash – from West Suffolk (v.-c. 26), East Norfolk in north-western Britain, especially eastern apart from a single record of a casual tuft on was the most popular host tree (Atlas), and SO2 (v.-c. 27), Northamptonshire (v.-c. 32) and Scotland, but it not particularly common, and elder in West Norfolk (v.-c. 28) in 1989. Recent pollution probably rendered England unsuitable North-east Yorkshire (v.-c. 62) – have the feel also grows on Sarsen Stones at a few sites in records have been: on willow in carr, Gunpowder for O. obtusifolium by the 1900s. British plants of of casual colonies rather than lost natives. There southern England. It is a frequent epiphyte in Park, Waltham Abbey, South Essex (v.-c. 18) O. obtusifolium are often extremely small, and have been two recent southern British records, much of Europe, and was found on apple at The in 2006; in Warboys Wood, Huntingdonshire might be confused with a Zygodon when dry, on an ash trunk at Kensall Quarry, Hertfordshire Royal Orchards, Flitcham, West Norfolk (v.-c. (v.-c. 31) in 2011; on apple in an orchard at but the acute leaf apex of all Zygodon except (v.-c. 20 in 2010, on an ash trunk at Abergavenny 28) in 2005. There is also a record from Spurn, Elm, Cambridgeshire (v.-c. 29) in 2007; on for Z. conoideus var. lingulatus provides a quick in Monmouthshire (v.-c. 35) in 2011, and one South-east Yorkshire (v.-c. 62), a prime site for ash by the Severn, north of Gloucester, West distinction. from northern England on ash by the River vagrant birds, in 1968, and an extraordinary Gloucestershire (v.-c. 34) in 2011; and on a Wear near Low Harperley, Co. Durham (v.-c. one from a churchyard wall top in Paddington street tree maple in Aberystwyth, Cardiganshire x Orthotrichum pallens is rather an anonymous 66) in 2000. Many authors split O. pumilum Green, Middlesex (v.-c. 21) in 2004. All three (v.-c. 46) in 2008. This species is remarkably species and is easy to overlook, so the paucity into two European species: the slightly taller, of these colonies seem likely to have originated common as an epiphyte on street trees in parts of British records may in part reflect confusion more northern/montane O. pumilum s.s. and from the continent, rather than from British of north-eastern France (SDSB, pers. obs.), and over its identification. It has a short, hairless, the extremely squat, lowland Mediterranean colonies, although it is impossible to be sure. www.verspreidingsatlas.nl shows 94 records pale calyptra with an orange tip and perhaps O. schimperi. Dixon (1924) reports the historic This species has a very hairy calyptra and its eight from The Netherlands, mostly from the south. most closely resembles a small O. stramineum, British records as O. schimperi, and both of the exostome teeth are upright when dry. The concentration of historic records in the although it would be simple to dismiss a tuft recent southern records are of that taxon. The English Midlands is peculiar, and may reflect as an odd form of O. affine or O. tenellum. five east Scottish and Co. Durham records are x Orthotrichum shawii has only been recorded the activities of a small number of bryologists, All five historic English records come from more likely to be O. pumilum s.s. given its range from one British site, Kilkerran Castle in Ayrshire for example J.E. Bagnall (8 sites), H.N. Dixon the north of the country, and there are recent in Scandinavia, but more work is needed on this (v.-c. 75) in 1860. This colony may have been the (8 sites) and H.H. Knight (4 sites), who knew records from Addingham, Wharfedale, Mid- species pair in Britain. result of a vagrant spore, but as it was recorded west Yorkshire (v.-c. 62) in 2005, and from on the non-native Fraxinus ornus it could con- , Orthotrichum obtusifolium. Andy Amphlett Weardale, Co. Durham (v.-c. 66) from 1999 , Orthotrichum pumilum. Graham Motley ceivably have been an importation. There seems onwards, and O. pallens is clearly well established a reasonable chance in Weardale (Hodgetts, 2003). It is hard to tell that O. shawii could whether some other historic records were of reappear in Britain, per- casual plants derived from Scandinavian spores. haps in upland areas The only southern British records were made of England because by Chris Tipper on willow at Cassiobury Park, of its predominantly Watford, Hertfordshire (v.-c. 20) in 2007, and upland distribution by Sam Bosanquet on field maple in a hedge in southern Europe. near Dingestow, Monmouthshire (v.-c. 35) There are recent rec- in 2011, both of which are likely to have been ords from two sites vagrants. in The Netherlands. It looks rather like x Orthotrichum pumilum is the most diminutive O. striatum, with a British Orthotrichum, and looks much more more or less smooth squat than O. tenellum, with short, hairless capsule and recurved calyptrae that only partly cover the capsules, exostome teeth, but rather than the long, slightly hairy calyptrae of its endostome is rudi-

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mentary. R.V. Lansdown (pers. comm.) has twice Its conspicuousness may explain why this species There have been numerous additions (Lawley, found O. striatum with a damaged/rudimentary has been found relatively regularly in southern 2010), many of them just as subtle as those endostome in Gloucestershire: the specimens’ England, despite being uncommon and mostly on Crundwell’s list. Orthotrichum acuminatum 30 μm wide spores confirmed the identification. montane in Europe. Records are: Combe St is the only southern spreader recorded new to Nicholas, South Somerset (v.-c. 5) before 1926; Britain in this time, but O. consimile, Grimmia x Orthotrichum speciosum appears to have Winters Down, South Hampshire (v.-c. 11) in tergestina and Sematophyllum substrumulosum retreated from England to Scotland since 1958; a willow in North Hampshire (v.-c. 12) have all arrived in England following previous the 20th century, as befits a species that is in 2008; Danny, West Sussex (v.-c. 13) in the records of outlying northern populations, in commoner than O. affine in all but the southern 19th century; willow at Slindon, West Sussex (v.- West Sussex (v.-c. 13), Argyll/Mull (v.-c. 98/103) parts of Scandinavia and is also frequent in c. 13) in 2000 and still present in 2011; willow and West Sussex (v.-c. 13) respectively. At least the mountains of Europe. It is quite possible at Brandy Hole Copse, West Sussex (v.-c. 13) 10 other epiphytes might appear in Britain that the four historic English records – from n Map showing known records of vagrant Orthotrichum in 2011; willow at Ham Street, East Kent (v.- judging by their European distribution or recent Hurstpierpoint and Henfield, West Sussex species in England and Wales. d, post-2000 record of c. 15) in 2004; Glover’s Wood, Surrey (v.-c. 17) arrival in Belgium or the Netherlands. Having (v.-c. 13), Tilgate Forest, East Sussex (v.-c. 14) at least one ‘vagrant’ Orthotrichum or Ulota coarctata; in 2006; Pitstone Common, Buckinghamshire a search image for these species will give British and Stockton Forest, North-east Yorkshire (v.- +, pre-2000 records of these species. (v.-c. 24) in 2010; a chestnut at Aylmerton, bryologists a better chance of detecting any that c. 62) – were of casual colonies, and they have not have been checked critically (T. Blockeel, East Norfolk (v.-c. 27) in 1907; and a poplar arrive. Data on records from The Netherlands been followed by a 1999 record from Salix pers. comm.). There have been 24 recent records at Nineveh, Worcestershire (v.-c. 37) in 1992. come from www.verspreidingsatlas.nl. alba near Wolsingham, Co. Durham (v.-c. 66) from The Netherlands (www.verspreidingsatlas. Recent records of this species are much more and three 20th century records, from willow at nl), probably deriving from gemmae transported concentrated in south-east England than those x Orthotrichum alpestre has been found at a Wigginton, near Tring, Hertfordshire (v.-c. 20) from upland area of Europe. This species of most vagrant Orthotrichum. single Dutch site on a sycamore bole in young, in 2008, ash at Balsham Wood, Cambridgeshire resembles a diminutive Pterogonium gracile and planted woodland at sea level. It is frequent on (v.-c. 29) in 2008 and apple in an orchard at has down-curved branches. Potential additions to the British list rocks in the Scandinavian mountains, as well as Wisbech, Cambridgeshire (v.-c. 29) in 2009. Predicting additions to the British list is a game further south in Europe, and also occurs occa- O. affine can be a more of a confusion problem x Ulota calvescens has a similar range to Daltonia that many birders play, and the same can be done than the Floras suggest, as some populations splachnoides and, like that species, appears from for bryophytes. Birding World often features have relatively exserted capsules and hairy recent records to be spreading eastwards in identification articles on gulls or warblers that calyptrae, for example at sites in Gloucestershire Ireland. It is now frequent on willows in conifer have yet to be recorded in Britain, and within (R.V. Lansdown, pers. comm.) and West Sussex plantations in Co. Tipperary (v.-c. H7 & H10) a few months a first for Britain is found, in part (SDSB, pers. obs.). True O. speciosum is quite (SDSB, pers. obs.) as well as further south-west. because people have been armed with a search striking, and the ill-defined capsule striae provide There are two historic records from north Wales, image. Alan Crundwell’s list of 10 liverworts a useful identification feature in addition to the but the only recent record was of a single tuft on and 17 mosses present in Europe but not exserted capsule and acuminate leaves. a willow in southern Pembrokeshire (v.-c. 45), Britain (Crundwell, 1992) does not include which was clearly a spore vagrant from the west. x Pterigynandrum filiforme has occurred any northward-spreading species or epiphytes, It is highly likely that two West Cornish (v.-c. 1) recently as a vagrant to Wordwell, West Suffolk probably because he was writing at the end of records on willow, the only ones for U. calvescens (v.-c. 25) and an orchard at Elm, Cambridgeshire a long period of epiphyte decline, and is made from England, also derive from spores of Irish (v.-c. 29), and was also reported south-east of up of various subtle, mostly northern species origin. its upland British range at Ashford, Derbyshire that could have been overlooked in Britain. Only (v.-c. 57) in 1840 and on a tree in a hedge near x Ulota coarctata is relatively easy to spot, Nardia insecta and Cinclidotus riparius have been Sennybridge, Breconshire (v.-c. 42) in 1907, because of its unique club-shaped capsule with confirmed in the subsequent 19 years, whilst although the Derbyshire specimen is in the a small mouth; it also has straighter leaves when Dicranella howei is probably present (Smith, 2004; private Chatsworth House herbarium and may dry than the common U. bruchii and U. crispa. Bosanquet, 2010) but remains unconfirmed. n Orthotrichum alprestre. Michael Lüth

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sionally as an epiphyte. Its calyptra has a dark tip and abundant, thick, strongly papillose hairs.

x Orthotrichum casasianum is a bit of a long shot, recorded only from riparian woodland in northern Spain (Blockeel, 2006), but could conceivably appear in south-western Britain. It resembles O. pallens, with a hairless calyptra, but n Orthotrichum patens. Michael Lüth typically has a hooded leaf tip and a seta that is the same brown colour as the ripe capsule, checked have proved to be O. affine. It is whereas the seta of O. pallens is contrastingly increasing in The Netherlands (van der Pluijm, light brown. 2004), with 37 records since 1990, and is widespread in Europe and common in parts x Orthotrichum hispanicum has been recorded of Germany (e.g. Nebel & Philippi, 2001). once from The Netherlands, and is otherwise This species shares the dark calyptra tip and known from the Mediterranean between Spain hairy vaginula of O. stramineum with the and Turkey, with an outlying colony in Kashmir. slightly hairy calyptra and loosely tufted Its conspicuous, emergent, wide-mouthed, appearance of O. affine, so plants that appear yellow capsules should draw attention. somewhat intermediate between these two common species should be checked carefully, x Orthotrichum ibericum has been collected with a focus on the width of the bands of thick- once in Belgium but is otherwise restricted to the walled cells on the capsule. Iberian Peninsula (Blockeel, 2006) and Cyprus. It has an even more rudimentary peristome than x Orthotrichum philibertii looks similar to O. O. acuminatum, with both the endostome and pumilum, with a short, more or less non-plicate exostome short or absent. The upper sixth of the calyptra, but has papillose calyptra hairs and capsule is sulcate, but the remainder is smooth. parallel-sided leaves that taper suddenly at the Along with O. acuminatum and O. shawii, tip. There are a few records from base-rich bark this species highlights the need to routinely in south-western Norway but none from The check the peristome of any O. striatum seen in Netherlands. Britain, although the long seta and very exserted capsule of O. ibericum make it look more like O. x Orthotrichum rogeri is almost endemic to speciosum. Europe, with outlying populations in north-east x Orthotrichum macrocephalum resembles O. Turkey, is on the Red List of many European sprucei because of its rounded leaf tips, but has countries and is included on Annex 2 of the smaller cells and is not associated with rivers. Habitats and Species Directive. However, it It has not yet been recorded north of the seems to be rather like Hamatocaulis vernicosus Mediterranean. (Bosanquet et al., 2006), with several countries n From top to bottom: Orthotrichum hispanicum, claiming to be the centre of its distribution. It x Orthotrichum patens has been claimed before O. ibericum and O. macrocephalum. Ricardo Gariletti is similar in appearance to O. tenellum, with a n Orthotrichum rogeri (top) and O. philibertii (bottom). in Britain (Smith, 1978), but all specimens (O. hispanicum) & Michael Lüth relatively long, slightly dark-tipped calyptra, Michael Lüth

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sionally as an epiphyte. Its calyptra has a dark tip and abundant, thick, strongly papillose hairs. x Orthotrichum casasianum is a bit of a long shot, recorded only from riparian woodland in northern Spain (Blockeel, 2006), but could conceivably appear in south-western Britain. It resembles O. pallens, with a hairless calyptra, but n Orthotrichum patens. Michael Lüth typically has a hooded leaf tip and a seta that is the same brown colour as the ripe capsule, checked have proved to be O. affine. It is whereas the seta of O. pallens is contrastingly increasing in The Netherlands (van der Pluijm, light brown. 2004), with 37 records since 1990, and is widespread in Europe and common in parts x Orthotrichum hispanicum has been recorded of Germany (e.g. Nebel & Philippi, 2001). once from The Netherlands, and is otherwise This species shares the dark calyptra tip and known from the Mediterranean between Spain hairy vaginula of O. stramineum with the and Turkey, with an outlying colony in Kashmir. slightly hairy calyptra and loosely tufted Its conspicuous, emergent, wide-mouthed, appearance of O. affine, so plants that appear yellow capsules should draw attention. somewhat intermediate between these two common species should be checked carefully, x Orthotrichum ibericum has been collected with a focus on the width of the bands of thick- once in Belgium but is otherwise restricted to the walled cells on the capsule. Iberian Peninsula (Blockeel, 2006) and Cyprus. It has an even more rudimentary peristome than x Orthotrichum philibertii looks similar to O. O. acuminatum, with both the endostome and pumilum, with a short, more or less non-plicate exostome short or absent. The upper sixth of the calyptra, but has papillose calyptra hairs and capsule is sulcate, but the remainder is smooth. parallel-sided leaves that taper suddenly at the Along with O. acuminatum and O. shawii, tip. There are a few records from base-rich bark this species highlights the need to routinely in south-western Norway but none from The check the peristome of any O. striatum seen in Netherlands. Britain, although the long seta and very exserted capsule of O. ibericum make it look more like O. x Orthotrichum rogeri is almost endemic to speciosum. Europe, with outlying populations in north-east x Orthotrichum macrocephalum resembles O. Turkey, is on the Red List of many European sprucei because of its rounded leaf tips, but has countries and is included on Annex 2 of the smaller cells and is not associated with rivers. Habitats and Species Directive. However, it It has not yet been recorded north of the seems to be rather like Hamatocaulis vernicosus Mediterranean. (Bosanquet et al., 2006), with several countries n From top to bottom: Orthotrichum hispanicum, claiming to be the centre of its distribution. It x Orthotrichum patens has been claimed before O. ibericum and O. macrocephalum. Ricardo Gariletti is similar in appearance to O. tenellum, with a n Orthotrichum rogeri (top) and O. philibertii (bottom). in Britain (Smith, 1978), but all specimens (O. hispanicum) & Michael Lüth relatively long, slightly dark-tipped calyptra, Michael Lüth

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Blockeel, T.L. (2010). Persisting introductions: a new bryophyte recording category. Field Bryology 101, 54–55. Bosanquet, S.D.S., Hale, A.D., Motley, G.S. & Woods, R.G. (2006). Recent work on Hamatocaulis vernicosus in mid and south Wales. Field Bryology 90, 2–8. Bosanquet, S.D.S., Coote, L., Kelly, D.L., Long, D.G. & Preston, C.D. (2010). Daltonia splachnoides in Irish conifer plantations – another epiphyte on the move. Field Bryology 100, 16–21. Crundwell, A.C. (1992). n Orthotrichum scanicum. Michael Lüth (left), Ricardo Gariletti (right) n Zygodon dentatus .Michael Lüth The bryophytes of Britain and Ireland in a European context. In Atlas of the Bryophytes of Britain and Ireland, Volume 2, Acknowledgements but differs in having straight endostome teeth Table 1 overleaf summarizes the main identification Mosses (except Diplolepideae). Edited by M.O. Hill, C.D. Tom Blockeel provided plenty of useful identification tips and (incurved in O. tenellum) and male branches features of all the Orthotrichum species listed Preston & A.J.E. Smith. Colchester: Harley Books. distribution information among his comments on an early with conspicuously broader leaves than female above. Dixon, H.N. (1924). The Student’s Handbook of British Mosses. draft, whilst Chris Preston and Richard Lansdown’s comments branches. It has been seen recently at 17 sites in Eastbourne: Sumfield & Day. made me think harder about the nature of spore vagrancy. the Netherlands, where it is particularly frequent x Zygodon dentatus is an Alpine epiphyte that Paco Lara sent me PDFs of several Orthotrichum papers, Greven, H. (2011). Ecology and distribution of Grimmia on Salix alba in young woodland, and also grows was recorded once in 1895 in southern Norway including descriptions of O. ibericum and O. macrocephalum, crinita Brid. Field Bryology 104, 18–21. on base-rich bark in south-western Norway. but has been found five times in The Netherlands and the excellent photographs of Ricardo Garilleti give British Hill, M.O. (2006). Rare and interesting bryophytes in Britain since 2001. Its leaves have conspicuous teeth bryologists a real search image for non-British Orthotrichum. and Ireland. Field Bryology 89, 43–45. Images of many of the species in this article can be found in x Orthotrichum scanicum is spreading in the near the apex and are somewhat crisped when Hodgetts, N.G. (2003). The status of Pale Bristle-moss Michael Lüth’s online Bildatlas der Moose Deutschlands (www. (Orthotrichum pallens) in Britain. Salisbury: Plantlife Report southern half of the Netherlands (van der dry, making loose patches of this plant resemble milueth.de/Moose/). Pluijm, 2004) and has been recorded at 26 sites a Ulota. British bryologists regularly check the No. 221. since the first record in 1987. It has slightly gemmae of Zygodon species, but need to examine Jones, E.W (1991). The changing bryophyte flora of Oxfordshire. Journal of Bryology 16, 513–549. flexuose leaves, a moderately exserted capsule specimens’ leaf tips as well. References Lawley, M. (2010). Developments in British and Irish field with pale exostome teeth, 16 endostome teeth, Bates, J.W. & Preston, C.D. (2011). Effects of climate change bryology during the decade 2000–2009. Field Bryology 101, Sam D.S. Bosanquet on British bryophytes. In Bryophyte Ecology and Climate and a very pale, almost white calyptra with a pale 13–20. yellowish tip. The capsule lid is taller and more Cnwc y Llwyn, Brechfa, Carmarthenshire Change. Edited by Z. Tuba, N.G. Slack & L.R. Stark. Cambridge: Cambridge University Press. Nebel, M. & Philippi, G. (eds.) (2001). Die Moose Baden- domed than that of related species and does not (e [email protected]) Württembergs Band 2. Stuttgart: Ulmer. Bates, J.W., Proctor, M.C.F., Preston, C.D., Hodgetts, N.G. have a contrasting reddish margin, unlike O. & Perry, A.R. (1997). Occurrence of epiphytic bryophytes Richardson, D.H.S. (1992). Pollution Monitoring with Lichens. Note added in proof pulchellum and O. tenellum. Checking that the in a ‘tetrad’ transect across southern Britain. 1. Geographical Slough: Richmond Publishing Company. peristome teeth of apparent O. pulchellum are red This article was written before the record of O. trends in abundance and evidence of recent change. Journal Smith, A.J.E. (1978). The Moss Flora of Britain and Ireland. is essential to avoid overlooking both this species scanicum from Derbyshire was published. It backs of Bryology 19, 685–714. Cambridge: Cambridge University Press. and O. consimile. Most leaves have a few teeth at up many of the feelings expressed in the article. See Blockeel, T.L. (ed.) (2006). The Liverworts, Mosses and Ferns Van der Pluijm, A. (2004). Species of Orthotrichum new to the the apex. Field Notes on p. 26. of Europe, English Edition. Colchester: Harley Books. Netherlands. Lindbergia 29, 17–32.

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Table 1. Summary of main identification features of Orthotrichum species

Species Epi./ GB Seta‡ Dry capsule Peristome Calyptra Vaginula Leaf Species sax.* freq.† Exostome Endostome Hairs length Tip Stomata§ Hairs Margins Apex

acuminatum E R Short Almost smooth Absent 8 incurved Abdt/sparse Mid Brown Exposed No Recurved Acuminate acuminatum affine E/S A Short Strongly furrowed 8 brown reflexed 8 incurved Sparse Mid Brown Exposed No Recurved Acute affine alpestre S/E Mid Strongly furrowed 8 brown reflexed 8/16 incurved Abdt papillose Short Purple ± hidden Yes Recurved Acuminate alpestre anomalum S(E) A Long Strongly furrowed 16 orange erect None Sparse/Abdt Short Brown V hidden No Recurved Acute anomalum casasianum E Mid Strongly furrowed 8 brown reflexed 16 incurved Absent Long Brown ± hidden No Recurved Obtuse, hooded casasianum consimile E R Long Strongly furrowed 8 whitish reflexed 8 incurved Absent Long Brown V hidden No Recurved Acute consimile cupulatum S F Short Strongly furrowed 16 pale erect None Sparse/Abdt Short Brown ± hidden Yes Recurved Obtuse/Acute cupulatum diaphanum S/E A Short Smooth or wrinkled 16 pale reflexed 16 incurved Sparse/None Mid Brown ± hidden No Recurved Hyaline diaphanum gymnostomum E R Short Almost smooth Absent Absent None/Sparse Mid Orange Exposed No Incurved Obtuse gymnostomum hispanicum E Mid Yellow, furrowed upper half 8/16 pale reflexed 16 incurved None/Sparse Mid Brown ± hidden No Recurved Acute hispanicum ibericum E Long Furrowed upper sixth Absent Absent Abundant Long Brown Exposed No Recurved Acuminate ibericum lyellii E(S) F Mid Furrowed 16 pale recurved 16 incurved Abundant Mid Brown Exposed No Plane Acuminate lyellii macrocephalum E Short Strongly furrowed 8 orange reflexed 8 incurved None Short Brown V hidden No Recurved Rounded macrocephalum obtusifolium E O Short Strongly furrowed 8 red reflexed 8 incurved None/Sparse Mid Brown Exposed No Plane Obtuse obtusifolium pallens E R Mid Strongly furrowed 8 pale reflexed 16 incurved None Short Orange ± exposed No Recurved Obtuse apiculate pallens patens E Mid Narrow ribs upper half 8 pale reflexed 8 incurved Sparse papillose Mid Brown V hidden Yes Recurved Acuminate patens philibertii E Mid Strongly furrowed 8 yellow reflexed 8 incurved Sparse papillose Short Brown ± hidden No Recurved Obtuse philibertii pulchellum E(S) F Long Strongly furrowed 16 red reflexed 16 incurved None Short Brown V hidden No Recurved Acuminate pulchellum pumilum E R Mid Strongly furrowed 8 orange reflexed 8 incurved None Short Orange ± hidden No Recurved Obtuse apiculate pumilum rivulare E/S F Short Strongly furrowed 8 brown reflexed 16 incurved None Mid Green V hidden No Recurved Toothed rivulare rogeri E Mid Strongly furrowed 8 brown reflexed 8/16 straight None Short Brown ± hidden No Recurved Obtuse/Acute rogeri rupestre S/E O Short Weakly furrowed 8 pale erect 0/8 incurved Abdt papillose Mid Brown Exposed No Recurved Acute rupestre scanicum E Short Narrow ribs upper half 16 pale reflexed 16 incurved Sparse/None Mid Yellow V hidden No Recurved Obtuse, toothed scanicum shawii E R Short Almost smooth 16 pale recurved Absent Abdt/Sparse Mid Brown Exposed No Recurved Acuminate shawii speciosum E O Long Furrowed upper half 8 brown recurved 8 incurved Abundant Mid Brown Exposed No Recurved Acuminate speciosum sprucei E O Mid Strongly furrowed 8 pale reflexed 8 incurved None Mid Orange V hidden No Recurved Rounded sprucei stramineum E F Mid Strongly furrowed 8 orange reflexed 8 incurved Sparse/None Mid Purple V hidden Yes Recurved Acuminate stramineum striatum E F Short Smooth 16 pale recurved 16 straight Abundant Mid Brown Exposed No Recurved Acuminate striatum tenellum E(S) F Mid Strongly furrowed 8 brown reflexed 8 incurved Sparse Long Brown V hidden No Recurved Obtuse tenellum

*E, Epipytic; S, saxicolous. †A, Abundant; F, frequent; o, occasional; r, rare. ‡Short, immersed-emergent; Mid, emergent; Long, exserted. §Exposed, phaneropore; ± exposed, cryptopore with short surrounding cells; ± hidden, cryptopore with medium-long surrounding cells; V hidden, cryptopore with surrounding cells meeting.

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Table 1. Summary of main identification features of Orthotrichum species

Species Epi./ GB Seta‡ Dry capsule Peristome Calyptra Vaginula Leaf Species sax.* freq.† Exostome Endostome Hairs length Tip Stomata§ Hairs Margins Apex acuminatum E R Short Almost smooth Absent 8 incurved Abdt/sparse Mid Brown Exposed No Recurved Acuminate acuminatum affine E/S A Short Strongly furrowed 8 brown reflexed 8 incurved Sparse Mid Brown Exposed No Recurved Acute affine alpestre S/E Mid Strongly furrowed 8 brown reflexed 8/16 incurved Abdt papillose Short Purple ± hidden Yes Recurved Acuminate alpestre anomalum S(E) A Long Strongly furrowed 16 orange erect None Sparse/Abdt Short Brown V hidden No Recurved Acute anomalum casasianum E Mid Strongly furrowed 8 brown reflexed 16 incurved Absent Long Brown ± hidden No Recurved Obtuse, hooded casasianum consimile E R Long Strongly furrowed 8 whitish reflexed 8 incurved Absent Long Brown V hidden No Recurved Acute consimile cupulatum S F Short Strongly furrowed 16 pale erect None Sparse/Abdt Short Brown ± hidden Yes Recurved Obtuse/Acute cupulatum diaphanum S/E A Short Smooth or wrinkled 16 pale reflexed 16 incurved Sparse/None Mid Brown ± hidden No Recurved Hyaline diaphanum gymnostomum E R Short Almost smooth Absent Absent None/Sparse Mid Orange Exposed No Incurved Obtuse gymnostomum hispanicum E Mid Yellow, furrowed upper half 8/16 pale reflexed 16 incurved None/Sparse Mid Brown ± hidden No Recurved Acute hispanicum ibericum E Long Furrowed upper sixth Absent Absent Abundant Long Brown Exposed No Recurved Acuminate ibericum lyellii E(S) F Mid Furrowed 16 pale recurved 16 incurved Abundant Mid Brown Exposed No Plane Acuminate lyellii macrocephalum E Short Strongly furrowed 8 orange reflexed 8 incurved None Short Brown V hidden No Recurved Rounded macrocephalum obtusifolium E O Short Strongly furrowed 8 red reflexed 8 incurved None/Sparse Mid Brown Exposed No Plane Obtuse obtusifolium pallens E R Mid Strongly furrowed 8 pale reflexed 16 incurved None Short Orange ± exposed No Recurved Obtuse apiculate pallens patens E Mid Narrow ribs upper half 8 pale reflexed 8 incurved Sparse papillose Mid Brown V hidden Yes Recurved Acuminate patens philibertii E Mid Strongly furrowed 8 yellow reflexed 8 incurved Sparse papillose Short Brown ± hidden No Recurved Obtuse philibertii pulchellum E(S) F Long Strongly furrowed 16 red reflexed 16 incurved None Short Brown V hidden No Recurved Acuminate pulchellum pumilum E R Mid Strongly furrowed 8 orange reflexed 8 incurved None Short Orange ± hidden No Recurved Obtuse apiculate pumilum rivulare E/S F Short Strongly furrowed 8 brown reflexed 16 incurved None Mid Green V hidden No Recurved Toothed rivulare rogeri E Mid Strongly furrowed 8 brown reflexed 8/16 straight None Short Brown ± hidden No Recurved Obtuse/Acute rogeri rupestre S/E O Short Weakly furrowed 8 pale erect 0/8 incurved Abdt papillose Mid Brown Exposed No Recurved Acute rupestre scanicum E Short Narrow ribs upper half 16 pale reflexed 16 incurved Sparse/None Mid Yellow V hidden No Recurved Obtuse, toothed scanicum shawii E R Short Almost smooth 16 pale recurved Absent Abdt/Sparse Mid Brown Exposed No Recurved Acuminate shawii speciosum E O Long Furrowed upper half 8 brown recurved 8 incurved Abundant Mid Brown Exposed No Recurved Acuminate speciosum sprucei E O Mid Strongly furrowed 8 pale reflexed 8 incurved None Mid Orange V hidden No Recurved Rounded sprucei stramineum E F Mid Strongly furrowed 8 orange reflexed 8 incurved Sparse/None Mid Purple V hidden Yes Recurved Acuminate stramineum striatum E F Short Smooth 16 pale recurved 16 straight Abundant Mid Brown Exposed No Recurved Acuminate striatum tenellum E(S) F Mid Strongly furrowed 8 brown reflexed 8 incurved Sparse Long Brown V hidden No Recurved Obtuse tenellum

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