THE BRYOPHYTES OF CORNWALL |
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| Introduction - Hornworts - Liverworts - Mosses - Coastal influences - Analysis - Bibliography - Acknowledgements - Links - CISFBR | ||
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COASTAL INFLUENCES ON BRYOPHYTE DISTRIBUTION Paton (1969a: 677) commented that
'although long stretches of the coast are rather dull bryologically, there
are many areas where interesting plants can be found'. Indeed, some of the
best known bryophyte rarities in Cornwall are known mainly or entirely
from coastal sites, including Cyclodictyon laetevirens, several
Fossombronia and Riccia spp. and Tortula wilsonii. Systematic
recording of tetrads since 1993 has nevertheless revealed that numerous
other bryophyte species are unaccountably scarce in coastal tetrads (e.g.
Microlejeunea ulicina, Orthotrichum pulchellum, Pogonatum aloides, Polytrichastrum formosum). In
fact, some pairs of closely related common species differ markedly in
their frequency in coastal habitats. Examples include Metzgeria furcata, Orthotrichum diaphanum and Ulota phyllantha which are common
within 1 km of coasts whereas M. consanguinea, O. affine and U. bruchii are notably scarce in the
same zone. Overall though, it appears that the coasts have reduced numbers
of bryophyte species. Thus, exposed coastal tetrads in West Cornwall have
a mean total of 53.7 taxa compared to means of 79.2 in less exposed
coastal tetrads and 93.3 and 83.0 in tetrads furthest inland (Table 2).
Admittedly the reduced land area available in the exposed coastal tetrads
must have some influence, but prolonged searching there does not yield
longer species lists. Species distribution in relation to the
proximity of the coast was analysed in detail in order to quantify the
differences between species and seek clues as to the factors causing the
differences. The data analysed was restricted to that from West Cornwall
and the Isles of Scilly, covering almost all of vice-county 1 (west of the
National Grid easting 18), because the author obtained almost complete
coverage of tetrads through personal recording in this region. Only data
from 1993-2010 was used, since the allocation of older records to tetrads
was often imprecise. Search times recorded during the author's fieldwork
also show that, overall, consistent amounts of time were spent examining
coastal, near-coastal and inland tetrads. 33,961 records were available
from 283 tetrads, a total reducing to 21,401 records when duplicates at
tetrad level were removed. 1:25,000 scale Ordnance Survey maps
were used to assign each tetrad to a Tetrad group according to the
distance to the sea from the nearest land (above HWST level) within the
tetrad (Table 2). The coastal tetrads were further subdivided into those
having all the land within 1.0 km of the sea (Tetrad group A: 'exposed
coastal tetrads') and those having some land >1.0 km from the sea
(group B). A Microsoft Excel spreadsheet was used to (i) sort records for
each taxon into Tetrad groups, (ii) count records within each Tetrad
group, and (iii) express occurrence as a percentage of tetrads occupied in
each Tetrad group, the resulting data being presented in Table 2. Rare
taxa (recorded from <16 tetrads) were excluded from the analyses
because many of their distribution patterns are unlikely to be
statistically significant. Alien species established mainly or entirely on
the Isles of Scilly (Lophocolea
bispinosa, L. semiteres, Riccia crystallina, Sematophyllum substrumulosum) were
also excluded. Species were assigned to categories of
coastal tolerance using definitions set out in Table 1. The range of
categories used extends from 'obligate halophyte', through 'highly
coast-tolerant' to 'highly intolerant of coasts'. Problems arose in
assigning some species to these categories. Most of the problematical
species had too few tetrad records for confidence that their allocation
was statistically justified (marked † in Table 2). Some species with more
numerous records were at or close to the boundaries between categories
within a continuum (e.g. Neckera
complanata could almost equally well be placed as 'intolerant of
coasts' or as showing 'low or moderate tolerance of coasts'). Some species
occurring mainly or entirely on sand dunes showed an obvious and easily
explicable deficit of records far inland (marked ‡ in Table 2), so not all
criteria could be used for these. A few other species appeared to qualify
for different categories depending on the weight given to different
criteria (e.g. Pohlia annotina
has some coastal records, despite an overall distribution of tetrad
frequences implying it is intolerant of coasts; possibly more than one
ecotype is involved). Finally,
five species listed at the end of Table 2 have 'data too irregularly
distributed to categorise'; these all have rather small numbers of tetrad
records and they include two strict
metallophytes. Nevertheless, many species can be
assigned with some confidence to a particular category, with evidence from
different criteria appearing congruent. For example, Grimmia lisae has only 18 tetrad
records, with 4 of them in exposed coastal sites and 8 more close to
coasts, implying high coast tolerance. Direct observations confirm this
species occurs on coastal slopes with very high levels of exposure to
salt-spray, e.g. at Sennen and near Kynance Cove on the Lizard.
The numbers of taxa in each category
are as follows:
obligate halophyte:
1 (Schistidium
maritimum)
strongly halophytic:
1 (Tortella flavovirens;
with Hennediella heimii not
analysed because it has too few records)
weakly halophytic: 9 (with additional rare
species similarly limited)
highly coast tolerant:
64
low or moderate coast tolerance: 94
intolerant of coasts: 22
highly intolerant of coasts: 29 data too
irregularly distributed to categorise species:
5
The number of taxa in each category is
dictated to some extent by the breadth of definition of the categories
themselves, with 'intolerant of coasts', for example, being more narrowly
defined than 'low or moderate coast tolerance'. However, it is clear that
many species show patterns of distribution affected by proximity to the
coast. There are of course many environmental
factors likely to affect bryophytes that vary in more or less systematic
ways in relation to distance from the coast. On average, coastal tetrads
are likely to have higher windspeeds, higher humidity, higher annual
insolation (less cloud cover on average), slightly higher mean annual
temperatures, less frequent frosts and lower average rainfall than inland
tetrads. They are also more likely to have basic or alluvial soils, but
the principal rock types in West Cornwall occur on the coasts as well as
inland and man-made masonry substrates are almost ubiquitous.
It might be expected that certain
bryophyte habitat types would be uncommon or lacking near the coasts, but
scrutiny of the species data suggests this is unimportant. The size of
tetrads is sufficient to often allow rocky streams (with Hygrohypnum ochraceum, Platyhypnidium riparioides),
acidic peaty mires (with Sphagnum
denticulatum, S. subnitens), large trees (with Cololejeunea minutissima, Ulota phyllantha), flushes, and
arable fields (with Anthoceros
punctatus, Bryum violaceum)
all to reach those tetrads on the coast. Also, many 'woodland species'
occur abundantly here in open coastal habitats, notably Mnium hornum on Cornish cliffs and
Dicranum majus in coastal
heathland on the Isles of Scilly. Hence absence or localisation of the
main habitat types does not explain most of the abundance or scarcity of
species in coastal areas. Patterns of bryophyte distribution
judged in relation to coastal proximity are likely to often have multiple
and complex causes. It is also reasonable to expect that some or even many
widespread bryophyte species may have ecotypes with different
physiological tolerances occurring in different parts of the region,
although relevant data are scarce. Nevertheless, exposure to sea-salt is
likely to be a significant variable affecting bryophyte distribution,
since only three bryophyte species of the region are strong or obligate
halophytes. Furthermore, bryophyte species numbers are conspicuously
reduced in coastal sites exposed to Atlantic gales, as on the small
spray-washed island of Annet (34 hectares; maximum elevation 19 m ASL) in
the south-west of the Isles of Scilly, which has a total recorded
bryoflora of only 14 species. Overall, it seems likely that salt tolerance
is one of the most important factors determining bryophyte distribution
near coasts in Scilly and W. Cornwall. Table 3 relates data on coastal
tolerance of bryophytes (from Table 2) to observational data on species
occurrence in saline coastal sites in the same region, showing there is at
least a general correlation. Detailed studies by Malloch (1971,
1972) showed that the primary factor in determining zonation of the
(phanerogam) vegetation on and above the cliffs at the Lizard pen. and
Land's End pen. is the intensity of salt deposition. The percentage
representation of maritime species within each plant community ('nodum')
was found to be very closely correlated with the mean sodium-organic ratio
of the soils (Malloch 1972: 109-110). The same author noted that direct
effects of salt deposition on woody plants can be observed after summer
gales up to 2-3 km inland, consisting of a blackening and withering of
leaves and young shoots on their windward side (Malloch 1972:
111). Sea-salt spray regularly extends far
inland during gales. During 16 years of residence in Tuckingmill (near
Camborne) windows of the author's house 3.7 km inland of the Atlantic
coast at 105 m altitude were coated with dried sea-salt several times
every winter. Malloch (1972: 106) found strong correlations between Na
deposition on the Lizard peninsula and the number of days with wind speeds
greater than 14 m s-1 (roughly equivalent to gale
force). Systematic
measurements on the Lizard pen. obtained over a period of more than two
years revealed mean Na deposition (from sea-salt, expressed as kg
ha-1
day-1) of
4.92 at 50 m from the west coast, 1.15 at 100 m inland, 0.54 at 500 m,
then 0.14 to 0.16 at 3.1 to 9.7 km inland of the west coast (Malloch 1972:
107). However, the lack of difference between his measurements from 3.1 to
9.7 km inland of the west coast may be misleading since most of those
localities are much closer to the south coast of the peninsula and hence
exposed to salt carried inland by southerly winds. Edwards & Claxton
(1964) found that in coastal areas near Aberystwyth Na deposition at 1.6
km from the coast (mean 0.57 kg ha-1
day-1)
was significantly higher than at 3.2, 4.8 or 6.4 km (with means of 0.41,
0.43 and 0.39 kg ha-1 day-1, respectively). There are reasons to expect that
epiphytes on vertical bark may be more exposed to sea-salt spray than
bryophytes growing on horizontal surfaces. Edwards & Claxton (1964)
gave values of sodium chloride deposited on a hawthorn hedge and grassland
during gales. The windward top of the hedge received 623 µg NaCl cm-2
whereas the grassland received 26 µg NaCl cm-2,
illustrating the effect of a hedge projecting above the level of the
surroundings. White & Turner (1970) showed that the catch of various
cations including Na on vertically held discs at right angles to air flow
was very much higher above the tree canopy than within it, and that smooth
young oak twigs are more efficient at catching Na than older rougher
twigs. Hence it may not be coincidental that a disproportionate number
of bryophyte epiphytes appear
in the lists of bryophyte species intolerant or highly intolerant of
coasts in W. Cornwall: Cryphaea
heteromalla, Metzgeria
violacea, Microlejeunea
ulicina, Neckera pumila, Orthotrichum affine, O. pulchellum, O. tenellum, Ulota bruchii, U. crispa, Zygodon conoideus. Their apparent
intolerance is not explicable merely in terms of lack of trees and bushes
within the coastal zone, since Cololejeunea minutissima, Frullania dilata, Orthotrichum diaphanum, Ulota phyllantha and Zygodon viridissimus var. viridissimus all find plenty of
bark substrates within the coastal zone. The absence from the Isles of Scilly or
great rarity there (*) of at least some bryophyte species which are common
on the 'mainland' of West Cornwall is in accordance with their intolerance
of coasts (notably Dicranella
schreberiana, Didymodon
nicholsonii, Homalia
trichomanoides, Hookeria
lucens, Hylocomium
splendens, Metzgeria
violacea*, Orthotrichum
affine*, O. pulchellum, Plagiomnium undulatum, Pleurozium schreberi, Pogonatum urnigerum, Pohlia nutans, Racomitrium lanuginosum, Ulota bruchii*, U. crispa). Intolerance of sea-salt
spray may explain their scarcity or absence in Scilly, as otherwise
suitable habitats appear to exist. On the other hand, other absentees from
Scilly or rarities there (*) may be better explained by lack of suitable
habitat, e.g. scarcity of basic open soil may limit or prevent occurrence
of Cratoneuron filicinum and Dicranella varia*, while the
virtual absence of streams excludes Fontinalis antipyretica and Hygrohypnum
ochraceum. The literature gives the impression
that very few bryophytes show any tolerance of salinity. For example, Hill
et al. (2007: 26) give the
Ellenberg indicator value for salt tolerance of British and Irish
bryophytes as S=0 (i.e. Absent from saline sites; if in coastal
situations, only accidental and non-persistent if subject to saline spray
or water) for 1013 taxa (96% of the total flora). This will only be true
if 'saline sites' are defined as those with persistent year-round salinity
with salt concentrations commonly approaching those of sea water.
Otherwise, it is contradicted by the persistent, regular occurrence of at
least 75 bryophyte species (see above) on exposed coastal slopes in
Cornwall and the Isles of Scilly that regularly receive salt
spray. Much more study is undoubtedly needed
to understand patterns of bryophyte distribution in relation to coastal
influences. Rather than the relatively crude tetrad data analysed here,
data on occurrences of individual populations of species in relation to
exposed and sheltered coasts would allow much more precise study.
Physiological studies or measurements of salinity tolerances exist for
very few bryophytes (Bates 1975, 1976, 2000; Bates & Brown 1974; Brown
1982). Even fewer studies have compared coastal and inland populations to
see if different ecotypes show differing salinity tolerances. However,
comparisons of the effect of seawater misting of inland and dune
populations of Polytrichum
commune, Aulacomnium
palustre and Ceratodon
purpureus by Boerner & Forman (1975) found that only C. purpureus showed any tolerance to
salt spray and then only when periodically watered with non-saline
solutions. The Cornish data show C. purpureus as highly
coast-tolerant (it often grows on exposed cliff tops) whereas P. commune is highly intolerant of
coasts (and never found in exposed coastal sites). A. palustre has too few tetrad data
for detailed analysis, but it completely lacks records from exposed
coasts. More investigation is needed of bryophyte tolerance of
intermittent salt spray. The Ellenberg value of S=0 noted above is
apparently a crude measure that conceals significant variability in
salinity responses which may affect the distribution patterns of many
bryophyte species in coastal regions.
TABLE 1. Definitions of coast-tolerance
categories. The definitions rely on patterns of
distribution judged from the tetrad records. Data set out in Table 2 were
used to assign species on the basis of percentages of tetrads occupied at
differing distances from the coast (ranging from exposed coastal tetrads
designated as Tetrad group A to tetrads more than 5 km from the sea
designated as Tetrad group G). % = percentage occurrence in Tetrad
group. obligate halophyte: %A>%B;
0% in C-G; strongly halophytic: %A>%B;
<11% in any of C-D; 0% in E-G; weakly halophytic: %A>%
in any of B-G or %A+%B > % in any of C-G; highly coast-tolerant: % in A
>0.7% in B; %A+%B not << twice mean % of C-G;
low or moderate coast
tolerance: % in A
>0.3 but < 0.7 % in B and % in B not < mean % in C-G;
intolerant of coasts: % in A
> 0.15 but <0.50 of % in B and % in B usually < mean % for C to
G; highly intolerant of
coasts: % in A from 0 to < 0.15 of % in B, usually % in B < or
<< mean % for C to G; data too irregularly distributed to categorise species.
TABLE 2. Data on distribution of bryophyte taxa in West
Cornwall in relation to distance from the sea. Taxa are assigned to categories of decreasing coast-tolerance
defined in Table 1. Within each category they are listed alphabetically.
Notes: † allocation to
category tentative because data are few; ‡ often or mainly occurring on
sand dunes.
Tetrad groups:
A
B
C
D
E
F
G minimum distance from sea (km) 0 0 0.1-1 1-2 2-3 3-5 5-9 maximum distance from sea (km) 1 ca 1-2 ca 2-3 ca 3-4 ca 4-5 ca 5-7 ca 7-11 total number of tetrads with data 52 72 40 34 27 31 27 total records of taxa 2792 5704 3046 2690 2036 2892 2241 mean number of taxa 53.7 79.2 76.2 79.1 75.4 93.3 83.0
obligate halophyte: Schistidium maritimum 37 23 0 0 0 0 0 percent. of tetrads 71.2 31.9 0 0 0 0 0
strongly halophytic: Tortella flavovirens 48 52 4 1 0 0 0 percent. of tetrads 92.3 72.2 10.0 2.9 0 0 0
weakly halophytic: Amblystegium serpens var. salinum‡ 4 14 1 1 0 0 0 percent. of tetrads 7.7 19.4 2.5 2.9 0 0 0
Archidium alternifolium 31 30 7 9 5 8 9 percent. of tetrads 59.6 41.7 17.5 26.5 18.5 25.8 33.3
Cephaloziella divaricata 19 15 6 5 1 9 6 percent. of tetrads 36.5 20.8 15.0 14.7 3.7 29.0 22.2
Cephaloziella hampeana 6 10 0 2 0 4 3 percent. of tetrads 11.5 13.9 0 5.9 0 12.9 11.1
Frullania microphylla† 7 8 0 0 0 0 0 percent. of tetrads 13.5 11.1 0 0 0 0 0
Riccia crozalsii 8 11 1 0 0 0 0 percent. of tetrads 15.4 15.3 2.5 0 0 0 0
Tortula atrovirens 6 13 0 0 0 0 0 percent. of tetrads 11.5 18.1 0 0 0 0 0
Tortula viridifolia 24 18 1 0 0 0 0 percent. of tetrads 46.2 25.0 2.5 0 0 0 0
Weissia perssonii 9 10 0 0 0 0 0 percent. of tetrads 17.3 13.9 0 0 0 0 0
highly coast-tolerant: Amblystegium serpens var. serpens 31 59 36 33 23 31 25 percent. of tetrads 59.6 81.9 90.0 97.1 85.2 100.0 92.6
Anthoceros punctatus† 5 4 1 4 0 3 2 percent. of tetrads 9.6 5.6 2.5 11.8 0 9.7 7.4
Barbula convoluta var. convoluta 28 51 31 26 19 26 21 percent. of tetrads 53.8 70.8 77.5 76.5 70.4 83.9 77.8
Barbula convoluta var. sardoa 21 45 30 21 18 22 19 percent. of tetrads 40.4 62.5 75.0 61.8 66.7 71.0 70.4 Barbula unguiculata 28 62 33 24 22 30 25 percent. of tetrads 53.8 86.1 82.5 70.6 81.5 96.8 92.6
Brachythecium albicans 33 36 11 8 4 7 8 percent. of tetrads 43.5 50.0 27.5 23.5 14.8 22.6 29.6
Bryum alpinum 9 4 1 3 3 3 2 percent. of tetrads 17.3 5.6 2.5 8.8 11.1 9.7 7.4
Bryum bornholmense 7 8 3 6 5 1 0 percent. of tetrads 13.5 11.1 7.5 17.6 16.1 3.2 0
Bryum capillare 44 64 37 33 25 28 26 percent. of tetrads 84.6 88.9 92.5 97.1 92.6 90.3 96.3
Bryum dichotomum 47 68 36 31 24 29 25 percent. of tetrads 90.4 94.4 90.0 91.2 88.9 93.5 92.6
Bryum pseudotriquetrum 12 18 11 11 8 8 7 percent. of tetrads 23.1 25.0 27.5 32.4 29.6 25.8 25.9
Bryum rubens 26 45 26 19 14 22 13 percent. of tetrads 50.0 62.5 65.0 55.9 51.9 71.0 48.1
Bryum subapiculatum 14 15 5 4 1 3 8 percent. of tetrads 26.9 20.8 12.5 11.8 3.7 9.7 29.6
Bryum violaceum† 4 4 4 1 2 1 2 percent. of tetrads 7.7 5.6 10.0 2.9 7.4 3.2 7.4
Campylopus brevipilus 6 4 4 3 1 1 0 percent. of tetrads 11.5 5.6 10.0 8.8 3.7 3.2 0
Campylopus flexuosus 13 9 7 9 13 11 16 percent. of tetrads 25.0 12.5 17.5 26.5 48.1 35.5 59.3
Campylopus fragilis 32 34 8 8 11 9 4 percent. of tetrads 61.5 47.2 20.0 23.5 40.7 29.0 14.8
Campylopus introflexus 39 55 26 24 20 23 24 percent. of tetrads 75.0 76.4 65.0 70.6 74.1 74.2 88.9
Campylopus pyriformis 8 10 5 4 2 3 2 percent. of tetrads 15.4 13.9 12.5 11.8 7.4 9.7 7.4
Cephalozia bicuspidata records 14 21 12 14 9 13 6 percent. of tetrads 26.9 29.2 30.0 41.2 33.3 41.9 22.2
Cephaloziella stellulifera records 12 10 8 8 3 14 12 percent. of tetrads 23.1 13.9 20.0 23.5 11.1 45.2 44.4
Ceratodon purpureus 45 66 33 30 24 31 25 percent. of tetrads 86.5 91.7 82.5 88.2 88.9 100.0 92.6
Cololejeunea minutissima records 24 41 23 22 11 15 9 percent. of tetrads 46.2 56.9 57.5 64.7 40.7 48.4 33.3
Dicranum majus† 8 5 0 2 0 0 0 percent. of tetrads 15.4 6.9 0 5.9 0 0 0
Dicranum scoparium 28 43 18 14 18 25 23 percent. of tetrads 53.8 59.7 25.0 41.2 66.7 80.6 85.2
Didymodon tophaceus 27 55 22 21 14 24 17 percent. of tetrads 51.9 76.4 55.0 61.8 51.9 77.4 63.0
Didymodon vinealis 18 25 6 8 5 11 10 percent. of tetrads 34.6 34.7 15.0 23.5 18.5 35.5 37.0
Entosthodon obtusus 14 15 3 4 0 3 0 percent. of tetrads 26.9 20.8 7.5 11.8 0 9.7 0
Epipterygium tozeri 15 26 15 9 5 8 2 percent. of tetrads 28.8 36.1 37.5 26.5 18.5 25.8 7.4
Fissidens crispus 11 13 2 2 0 0 0 percent. of tetrads 21.2 18.1 5.0 5.9 0 0 0
Frullania dilatata records 31 54 34 28 19 29 20 percent. of tetrads 59.6 75.0 85.0 82.4 70.4 93.5 74.1
Frullania tamarisci 27 23 6 6 2 6 1 percent. of tetrads 51.9 31.9 15.0 17.6 7.4 19.4 3.7
Grimmia lisae† 4 8 1 1 1 2 1 percent. of tetrads 7.7 11.1 2.5 2.9 3.7 6.5 3.7
Gymnostomum viridulum† 3 3 2 2 3 5 4 percent. of tetrads 5.8 4.2 5.0 5.9 11.1 16.1 14.8
Homalothecium lutescens 7 11 4 2 3 2 3 percent. of tetrads 13.5 15.3 10.0 5.9 11.1 6.5 11.1
Homalothecium sericeum 29 40 18 17 13 13 10 percent. of tetrads 55.8 76.9 45.0 50.0 48.1 41.9 37.0
Hypnum cupressiforme var. lacunosum 41 44 15 12 14 16 12 percent. of tetrads 78.8 61.1 37.5 35.3 51.9 51.6 44.4
Hypnum cupressiforme var. resupinatum 44 66 38 33 26 31 26 percent. of tetrads 84.6 91.7 95.0 97.1 96.3 100.0 96.3
Hypnum jutlandicum 40 44 21 24 20 28 22 percent. of tetrads 76.9 61.1 52.5 70.6 74.1 90.3 81.5
Isothecium myosuroides var. myosuroides 27 49 34 27 21 29 21 percent. of tetrads 51.9 68.1 85.0 79.4 77.8 93.5 77.8
Kindbergia praelonga records 48 69 39 34 26 31 27 percent. of tetrads 92.3 95.8 97.5 100.0 96.3 100.0 100.0
Lophozia ventricosa records 14 5 2 3 2 2 5 percent. of tetrads 26.9 6.9 5.0 8.8 7.4 6.5 18.5
Metzgeria furcata records 30 56 31 25 17 29 25 percent. of tetrads 57.7 77.8 77.5 73.5 63.0 93.5 92.6
Mnium hornum 34 55 36 29 21 30 25 percent. of tetrads 65.4 76.4 90.0 85.3 77.8 96.8 92.6
Orthotrichum anomalum† 5 6 5 8 6 5 3 percent. of tetrads 9.6 8.3 12.5 23.5 22.2 16.1 11.1
Phascum cuspidatum 18 27 22 10 9 10 6 percent. of tetrads 34.6 37.5 55.0 29.4 33.3 32.3 22.2
Pleurochaete squarrosa‡ 8 10 3 0 0 0 0 percent. of tetrads 15.4 13.9 7.5 0 0 0 0
Polytrichum juniperinum 31 39 19 19 19 25 23 percent. of tetrads 59.6 54.2 47.5 55.9 70.4 80.6 85.2
Pseudocrossidium hornschuchianum 25 43 19 12 11 16 16 percent. of tetrads 48.1 59.7 47.5 35.3 40.7 51.6 59.3
Pseudoscleropodium purum 29 53 31 27 21 29 23 percent. of tetrads 55.8 73.6 77.5 79.4 77.8 93.5 85.2
Rhynchostegium megapolitanum‡ 10 11 1 0 0 0 1 percent. of tetrads 19.2 15.3 2.5 0 0 0 3.7
Riccia sorocarpa 21 19 5 5 2 6 2 percent. of tetrads 40.4 26.4 12.5 14.7 7.4 19.4 7.4
Riccia subbifurca 7 12 2 4 2 6 4 percent. of tetrads 13.5 16.7 5.0 11.8 7.4 19.4 14.8
Saccogyna viticulosa 8 11 2 1 1 1 1 percent. of tetrads 15.4 15.3 5.0 2.9 3.7 3.2 3.7
Scapania compacta 18 18 7 8 9 14 10 percent. of tetrads 34.6 25.0 17.5 23.5 33.3 45.2 37.0
Scapania gracilis† 9 3 2 1 1 2 3 percent. of tetrads 17.3 4.2 5.0 2.9 3.7 6.5 11.1
Scleropodium touretii 34 30 9 4 3 0 0 percent. of tetrads 65.4 41.7 22.5 11.8 11.1 0 0
Syntrichia ruralis var. ruraliformis‡ 19 18 3 2 0 2 0 percent. of tetrads 36.5 25.0 7.5 5.9 0 6.5 0
Trichostomum brachydontium 47 59 18 13 7 9 5 percent. of tetrads 90.4 81.9 45.0 38.2 25.9 29.0 18.5
Ulota phyllantha 37 53 39 32 25 29 25 percent. of tetrads 71.2 73.6 97.5 94.1 92.6 93.5 88.9
Weissia brachycarpa var. obliqua 7 12 3 7 2 2 2 percent. of tetrads 13.5 16.7 7.5 20.6 7.4 6.5 7.4
Weissia controversa var. controversa 22 38 14 13 10 17 12 percent. of tetrads 42.3 52.8 35.0 38.2 37.0 54.8 44.4
Weissia controversa var. densifolia 4 3 2 2 1 4 6 percent. of tetrads 7.7 4.2 5.0 5.9 3.7 12.9 22.2
Zygodon viridissimus var. viridissimus 31 59 31 25 18 15 12 percent. of tetrads 59.6 81.9 77.5 73.5 66.7 48.4 44.4
low or moderate coast tolerance: Aloina aloides† 2 9 5 2 1 3 1 percent. of tetrads 3.8 12.5 12.5 5.9 3.7 9.7 3.7
Aneura pinguis† 4 9 6 6 2 6 3 percent. of tetrads 7.7 12.5 15.0 17.6 7.4 19.4 11.1
Atrichum undulatum 6 30 27 25 18 29 21 percent. of tetrads 11.5 41.7 67.5 73.5 66.7 93.5 77.8
Brachythecium mildeanum† 2 6 2 4 1 5 1 percent. of tetrads 3.8 8.3 5.0 11.8 3.7 16.1 3.7
Brachythecium rivulare 8 40 26 19 15 21 14 percent. of tetrads 15.4 55.6 65.0 55.9 55.6 67.7 51.9
Brachythecium rutabulum 33 66 39 34 26 31 26 percent. of tetrads 63.5 91.7 97.5 100.0 96.3 100.0 96.3
Bryoerythrophyllum recurvirostrum 6 17 10 5 5 13 10 percent. of tetrads 11.5 23.6 25.0 14.7 18.5 41.9 37.0
Bryum argenteum 25 55 28 27 20 25 24 percent. of tetrads 48.1 76.4 70.0 79.4 74.1 80.6 88.9
Bryum donianum 9 22 8 7 3 10 6 percent. of tetrads 17.3 30.6 20.0 20.6 11.1 32.2 22.2
Bryum pallens† 2 5 4 2 4 8 4 percent. of tetrads 3.8 6.9 10.0 5.9 14.8 25.8 14.8
Bryum radiculosum 18 38 14 18 15 21 19 percent. of tetrads 34.6 52.8 35.0 52.9 55.6 67.7 70.4
Bryum ruderale 18 29 17 9 11 13 9 percent. of tetrads 34.6 40.3 42.5 26.5 40.7 41.9 33.3
Bryum sauteri† 5 12 5 2 3 2 0 percent. of tetrads 9.6 16.7 12.5 5.9 11.1 6.5 0
Calliergonella cuspidata 18 63 36 30 19 30 26 percent. of tetrads 34.6 87.5 90.0 88.2 70.4 96.8 96.3
Calypogeia arguta records 10 29 22 19 14 19 7 percent. of tetrads 19.2 40.3 55.0 55.9 51.9 61.3 25.9
Calypogeia fissa records 12 22 15 13 8 19 7 percent. of tetrads 23.1 30.6 37.5 38.2 29.6 61.3 25.9
Campylium stellatum† 2 12 7 7 3 4 0 percent. of tetrads 3.8 16.7 17.5 20.6 11.1 12.9 0
Chiloscyphus pallescens† 0 6 5 1 1 1 2 percent. of tetrads 0 8.3 12.5 2.9 3.7 3.2 7.4
Chiloscyphus polyanthos† 1 9 5 1 5 4 0 percent. of tetrads 1.9 12.5 12.5 2.9 18.5 12.9 0
Conocephalum conicum 4 27 14 9 4 3 2 percent. of tetrads 7.7 37.5 35.0 26.5 14.8 9.7 7.4
Cratoneuron filicinum 12 48 22 23 16 23 18 percent. of tetrads 23.1 66.7 55.0 67.6 59.3 74.2 66.7
Dicranella heteromalla 23 43 31 27 22 30 25 percent. of tetrads 44.2 59.7 77.5 79.4 81.5 96.8 92.6
Dicranella rufescens† 1 2 4 0 4 5 3 percent. of tetrads 1.9 2.8 10.0 0 14.8 16.1 11.1
Dicranella staphylina 13 27 25 23 15 19 18 percent. of tetrads 25.0 37.5 62.5 67.6 55.6 61.3 66.7
Dicranella varia 13 38 23 19 15 20 21 percent. of tetrads 25.0 52.8 57.5 55.9 55.6 64.5 77.8
Dicranoweisia cirrata† 2 8 9 9 6 9 14 percent. of tetrads 3.8 11.1 22.5 26.5 22.2 29.0 51.9
Didymodon fallax 8 22 6 7 8 5 1 percent. of tetrads 15.4 30.6 8.3 20.0 29.6 16.1 3.7
Didymodon insulanus 35 64 37 31 25 31 25 percent. of tetrads 67.3 88.9 92.5 91.2 92.6 100.0 92.6
Didymodon luridus 6 15 13 10 8 10 5 percent. of tetrads 11.5 20.8 32.5 29.4 29.6 32.3 18.5
Didymodon rigidulus 18 46 24 22 17 27 24 percent. of tetrads 34.6 63.9 60.0 64.7 63.0 87.1 88.9
Drepanocladus aduncus† 3 7 3 7 2 7 6 percent. of tetrads 5.8 9.7 7.5 20.0 7.4 22.6 22.2
Ephemerum minutissimum† 3 3 5 7 2 6 4 percent. of tetrads 5.8 4.2 12.5 20.6 7.4 19.4 14.8
Eurhynchium striatum 4 23 16 18 12 23 17 percent. of tetrads 7.7 31.9 40.0 52.9 44.4 74.2 63.0
Fissidens adianthoides† 4 13 5 7 3 6 1 percent. of tetrads 7.7 18.1 12.5 20.6 11.1 19.4 3.7
Fissidens bryoides var. bryoides 11 48 30 31 18 28 23 percent. of tetrads 21.2 66.7 75.0 91.2 66.7 90.3 85.2
Fissidens bryoides var. caespitans 9 22 14 11 15 14 13 percent. of tetrads 17.3 30.6 35.0 32.4 55.6 45.2 48.1
Fissidens dubius† 6 13 2 2 4 3 3 percent. of tetrads 11.5 18.1 5.0 5.9 14.8 9.7 11.1
Fissidens incurvus† 2 10 5 1 0 0 0 percent. of tetrads 3.8 13.9 12.5 2.9 0 0 0
Fissidens pusillus† 2 6 3 1 2 1 4 percent. of tetrads 3.8 8.3 7.5 2.9 7.4 3.2 14.8
Fissidens taxifolius var. taxifolius 8 46 27 21 12 20 10 percent. of tetrads 15.4 63.9 67.5 61.8 44.4 64.5 37.0
Fissidens viridulus 12 29 8 5 8 11 4 percent. of tetrads 23.1 40.3 20.0 14.7 29.6 35.5 14.8
Fontinalis squamosa† 2 4 3 4 4 2 6 percent. of tetrads 3.8 5.6 7.5 11.8 14.8 6.5 22.2
Fossombronia pusilla† 4 3 3 7 2 6 7 percent. of tetrads 7.7 4.2 7.5 20.6 7.4 19.4 25.9
Funaria hygrometrica 16 43 21 17 13 21 17 percent. of tetrads 30.8 59.7 52.5 50.0 48.1 67.7 63.0
Grimmia pulvinata 12 40 22 11 10 19 15 percent. of tetrads 23.1 76.9 55.0 32.4 37.0 61.3 55.6
Gymnocolea inflata† 4 4 7 9 4 13 11 percent. of tetrads 7.7 5.6 17.5 26.5 14.8 41.9 40.7
Hygrohypnum ochraceum† 3 2 4 3 5 3 7 percent. of tetrads 5.8 2.8 10.0 8.8 18.5 9.7 25.9
Hyocomium armoricum† 2 1 0 2 3 6 3 percent. of tetrads 3.8 1.4 0 5.9 11.1 19.4 11.1
Hypnum andoi 11 38 31 24 21 30 23 percent. of tetrads 21.2 52.8 77.5 70.6 77.8 96.8 85.2
Hypnum cupressiforme var. cupressiforme 9 27 9 7 9 8 16 percent. of tetrads 17.3 37.5 22.5 20.6 33.3 25.8 59.3
Lejeunea lamacerina 13 27 15 15 9 11 7 percent. of tetrads 25.0 37.5 37.5 44.1 33.3 35.5 25.9
Lophocolea bidentata 20 54 34 26 19 30 20 percent. of tetrads 38.5 75.0 85.0 76.5 70.4 96.8 74.1
Lophocolea heterophylla 8 27 17 14 5 17 6 percent. of tetrads 15.4 37.5 42.5 41.2 18.5 54.8 22.2
Lophozia bicrenata† 1 5 2 3 1 5 6 percent. of tetrads 1.9 6.9 5.0 8.8 3.7 16.1 22.2
Lophozia excisa† 3 6 0 1 0 4 1 percent. of tetrads 5.8 8.3 0 2.9 0 12.9 3.7
Lunularia cruciata 18 46 23 20 13 20 11 percent. of tetrads 34.6 63.9 57.5 58.8 48.1 64.5 40.7
Microbryum davallianum† 4 9 1 1 0 0 1 percent. of tetrads 7.7 12.5 2.5 2.9 0 0 3.7
Microbryum rectum† 4 10 2 1 0 3 1 percent. of tetrads 7.7 13.9 5.0 2.9 0 9.7 3.7
Nardia scalaris† 6 9 6 5 6 7 9 percent. of tetrads 11.5 12.5 15.0 14.7 22.2 22.6 33.3
Orthotrichum diaphanum 24 56 27 29 18 26 19 percent. of tetrads 46.2 77.8 67.5 85.3 66.7 83.9 70.4
Oxyrrhynchium hians 16 52 32 26 17 27 21 percent. of tetrads 30.8 72.2 80.0 76.5 63.0 87.1 77.8
Oxyrrhynchium pumilum 15 50 27 22 17 26 15 percent. of tetrads 28.8 69.4 67.5 64.7 63.0 83.9 55.6
Oxyrrhynchium speciosum† 5 12 4 3 0 0 0 percent. of tetrads 9.6 16.7 10.0 8.8 0 0 0
Pellia endiviifolia 7 26 11 6 4 5 1 percent. of tetrads 13.5 36.1 27.5 17.6 14.8 16.1 3.7
Phaeoceros laevis† 4 10 6 5 4 3 6 percent. of tetrads 7.7 13.9 15.0 14.7 14.8 9.7 22.2
Philonotis fontana† 2 4 5 6 7 12 6 percent. of tetrads 3.8 5.6 12.5 17.6 25.9 38.7 22.2
Physcomitrium pyriforme† 2 11 9 5 3 2 1 percent. of tetrads 3.8 15.3 22.5 14.7 11.1 6.5 3.7
Plagiochila porelloides† 1 11 4 4 1 5 2 percent. of tetrads 1.9 15.3 10.0 11.8 3.7 16.1 7.4
Plagiothecium nemorale 9 34 20 16 15 25 15 percent. of tetrads 17.3 47.2 50.0 67.6 55.6 80.6 55.6
Plagiothecium succulentum 10 37 20 20 16 23 18 percent. of tetrads 19.2 51.4 50.0 58.8 59.3 74.2 66.7
Platyhypnidium riparioides 17 40 24 15 11 14 13 percent. of tetrads 32.7 55.6 60.0 44.1 40.7 45.2 48.1
Pleuridium acuminatum 6 26 10 11 5 9 8 percent. of tetrads 11.5 36.1 25.0 32.4 18.5 29.0 29.6
Polytrichum piliferum 5 9 5 8 10 14 16 percent. of tetrads 9.6 12.5 12.5 23.5 37.0 45.2 59.3
Radula complanata† 1 9 6 4 0 2 1 percent. of tetrads 1.9 12.5 15.0 11.8 0 6.5 3.7
Rhynchostegiella tenella 6 23 14 8 5 9 10 percent. of tetrads 11.5 31.9 35.0 23.5 18.5 29.0 37.0
Rhynchostegium confertum 31 65 38 33 24 29 26 percent. of tetrads 59.6 90.3 95.0 97.1 88.9 93.5 96.3
Rhytidiadelphus squarrosus 19 47 39 31 21 30 25 percent. of tetrads 36.5 65.3 97.5 91.2 77.8 96.8 92.6
Riccardia chamedryfolia† 5 11 2 4 3 3 0 percent. of tetrads 9.6 15.3 5.0 11.8 11.1 9.7 0
Riccia glauca† 3 9 2 5 2 4 2 percent. of tetrads 5.8 12.5 5.0 14.7 7.4 12.9 7.4
Scapania undulata† 2 4 1 4 7 6 7 percent. of tetrads 3.8 5.6 2.5 11.8 25.9 19.4 25.9
Schistidium crassipilum 5 14 7 6 3 7 5 percent. of tetrads 9.6 19.4 17.5 17.6 11.1 22.6 18.5
Schistostega pennata† 2 4 3 4 3 3 3 percent. of tetrads 3.8 5.6 7.5 11.8 11.1 9.7 11.1
Sciuro-hypnum populeum 8 19 18 11 12 17 16 percent. of tetrads 15.4 26.4 45.0 32.4 44.4 54.8 59.3
Scorpiurium circinatum‡ 7 16 3 3 0 0 0 percent. of tetrads 13.5 22.2 7.5 8.8 0 0 0
Sphagnum denticulatum† 4 7 8 10 7 6 4 percent. of tetrads 7.7 9.7 20.0 29.4 25.9 19.4 14.8
Sphagnum subnitens† 2 5 3 6 4 3 0 percent. of tetrads 3.8 6.9 7.5 17.6 14.8 9.7 0
Syntrichia laevipila 8 21 9 5 3 1 1 percent. of tetrads 15.4 29.2 22.5 14.7 11.1 3.2 3.7
Syntrichia ruralis var. ruralis‡ 6 15 5 2 0 1 1 percent. of tetrads 11.5 20.8 12.5 5.9 0 3.2 3.7
Thamnobryum alopecurum 7 31 22 19 15 16 9 percent. of tetrads 13.5 43.1 55.0 55.9 55.6 51.6 33.3
Tortula muralis 33 67 33 30 24 30 26 percent. of tetrads 63.5 93.1 82.5 88.2 88.9 96.8 96.3
Tortula truncata 25 50 35 26 19 23 21 percent. of tetrads 48.1 69.4 87.5 76.5 70.4 74.2 77.8
Trichodon cylindricus 12 26 23 22 13 22 19 percent. of tetrads 23.1 36.1 57.5 64.7 48.1 71.0 70.4
Trichostomum crispulum 5 16 4 3 3 2 1 percent. of tetrads 9.6 22.2 10.0 8.8 11.1 6.5 3.7
Zygodon viridissimus var. stirtonii 6 26 9 8 8 8 3 percent. of tetrads 11.5 36.1 22.5 23.5 29.6 25.8 11.1
intolerant of coasts: Cryphaea heteromalla records 8 39 32 26 23 29 19 percent. of tetrads 15.4 54.2 80.0 76.5 85.2 93.5 70.4
Diplophyllum albicans records 7 21 15 16 14 24 15 percent. of tetrads 13.5 29.2 37.5 47.1 51.9 77.4 55.6
Hedwigia stellata† 1 5 6 6 5 4 2 percent. of tetrads 1.9 6.9 15.0 17.6 18.5 12.9 7.4 Leptodictyum riparium† 2 17 7 5 4 2 5 percent. of tetrads 3.8 23.6 17.5 14.7 14.8 6.5 18.5
Metzgeria consanguinea records 4 20 18 13 11 22 7 percent. of tetrads 7.7 27.8 45.0 38.2 40.7 71.0 25.9 Microlejeunea ulicina records 3 16 17 14 9 20 9 percent. of tetrads 5.8 22.2 42.5 41.2 33.3 64.5 33.3
Neckera complanata 5 28 13 15 11 5 2 percent. of tetrads 9.6 38.9 32.5 44.1 40.7 16.1 7.4
Pellia epiphylla records 5 18 16 13 11 20 9 percent. of tetrads 9.6 25.0 40.0 38.2 40.7 64.5 33.3
Pohlia annotina 5 12 15 16 16 21 17 percent. of tetrads 9.6 16.7 37.5 67.6 59.3 67.7 63.0
Pohlia melanodon 1 19 10 12 6 7 3 percent. of tetrads 1.9 26.4 25.0 35.3 22.2 22.6 11.1
Pseudephemerum nitidum 2 11 9 11 11 12 10 percent. of tetrads 3.8 15.3 22.5 32.4 40.7 38.7 37.0
Pseudocrossidium revolutum† 1 9 1 1 3 3 4 percent. of tetrads 1.9 12.5 2.5 2.9 11.1 9.7 14.8
Pseudotaxiphyllum elegans 6 24 20 17 13 28 20 percent. of tetrads 11.5 33.3 50.0 50.0 48.1 90.3 74.1
Ptychomitrium polyphyllum 2 12 6 4 5 9 11 percent. of tetrads 3.8 16.7 15.0 11.8 18.5 29.0 40.7
Racomitrium aciculare† 1 5 5 2 4 6 6 percent. of tetrads 1.9 6.9 12.5 5.9 14.8 19.4 22.2
Racomitrium heterostichum 2 6 8 7 9 11 12 percent. of tetrads 3.8 8.3 20.0 20.6 33.3 35.5 44.4
Rhizomnium punctatum 3 26 22 18 12 15 14 percent. of tetrads 5.8 36.1 55.0 52.9 44.4 48.4 51.9
Sciuro-hypnum plumosum† 1 14 9 6 9 6 8 percent. of tetrads 1.9 19.4 22.5 17.6 33.3 19.4 29.6
Solenostoma gracillimum 2 10 9 11 8 8 16 percent. of tetrads 3.8 13.9 22.5 32.4 29.6 25.8 59.3
Syntrichia montana 3 15 9 9 1 1 5 percent. of tetrads 5.8 20.8 22.5 26.5 3.7 3.2 18.5
Thuidium tamariscinum 4 25 17 21 17 21 18 percent. of tetrads 7.7 34.7 42.5 61.8 63.0 67.7 66.7
Zygodon conoideus var. conoideus 5 22 16 14 17 22 14 percent. of tetrads 9.6 30.6 40.0 41.2 63.0 71.0 51.9
highly intolerant of coasts: Cirriphyllum crassinervium† 0 10 3 2 1 1 1 percent. of tetrads 0 13.9 7.5 5.9 3.7 3.2 3.7
Cirriphyllum piliferum† 0 7 3 4 2 1 1 percent. of tetrads 0 9.7 7.5 11.8 7.4 3.2 3.7
Dicranella schreberiana 2 20 17 12 10 14 9 percent. of tetrads 3.8 27.8 42.5 35.3 37.0 45.2 33.3
Didymodon nicholsonii 2 25 15 10 8 10 4 percent. of tetrads 3.8 34.7 20.8 29.4 29.6 32.3 14.8
Fontinalis antipyretica var. antipyretica† 0 9 3 2 1 2 5 percent. of tetrads 0 12.5 7.5 5.9 3.7 6.5 18.5
Gyroweisia tenuis† 0 3 2 1 1 6 3 percent. of tetrads 0 4.2 5.0 2.9 3.7 19.4 11.1
Homalia trichomanoides† 0 6 2 4 3 1 0 percent. of tetrads 0 8.3 5.0 11.8 11.1 3.2 0
Hookeria lucens 2 29 18 21 7 14 3 percent. of tetrads 3.8 40.3 45.0 61.8 25.9 45.2 11.1
Hylocomium splendens† 0 1 2 3 2 4 3 percent. of tetrads 0 1.4 5.0 8.8 7.4 12.9 11.1
Metzgeria violacea records 3 30 26 15 14 22 15 percent. of tetrads 5.8 41.7 65.0 44.1 51.9 71.0 55.6
Neckera pumila 0 15 6 8 5 10 2 percent. of tetrads 0 20.8 15.0 23.5 18.5 32.3 7.4
Orthotrichum affine records 2 32 21 21 20 29 21 percent. of tetrads 3.8 44.4 52.5 61.8 74.1 93.5 77.8
Orthotrichum pulchellum 1 13 16 11 9 16 11 percent. of tetrads 1.9 18.1 40.0 32.4 33.3 51.6 40.7
Orthotrichum tenellum† 0 13 4 5 4 5 4 percent. of tetrads 0 18.1 10.0 14.7 14.8 16.1 14.8
Plagiomnium undulatum 1 30 24 23 15 22 19 percent. of tetrads 1.9 41.7 60.0 67.6 55.6 71.0 70.4
Plagiothecium denticulatum var. denticulatum 1 13 9 11 5 16 12 percent. of tetrads 1.9 18.1 22.5 32.4 18.5 51.6 44.4
Pleurozium schreberi† 0 1 4 2 2 3 7 percent. of tetrads 0 1.4 10.0 5.9 7.4 9.7 25.9
Pogonatum aloides 0 17 14 12 7 16 9 percent. of tetrads 0 23.6 35.0 35.3 25.9 51.6 33.3
Pogonatum urnigerum† 0 2 2 2 4 6 4 percent. of tetrads 0 2.8 5.0 5.9 14.8 19.4 14.8
Pohlia andalusica 0 3 3 5 4 10 8 percent. of tetrads 0 4.2 7.5 14.7 14.8 32.3 29.6
Pohlia nutans 1 9 10 7 10 13 11 percent. of tetrads 1.9 12.5 25.0 20.6 37.0 41.9 40.7
Pohlia wahlenbergii var. wahlenbergii 0 7 4 3 5 10 7 percent. of tetrads 0 9.7 10.0 8.8 18.5 32.3 25.9
Polytrichastrum formosum 2 21 14 12 13 21 18 percent. of tetrads 3.8 29.2 35.0 35.3 48.1 67.7 66.7
Polytrichum commune var. commune† 0 2 4 4 3 7 6 percent. of tetrads 0 2.8 10.0 11.8 11.1 22.6 22.2
Racomitrium ericoides† 0 1 3 0 2 2 5 percent. of tetrads 0 1.4 7.5 0 7.4 6.5 18.5
Racomitrium lanuginosum† 0 4 4 1 3 5 3 percent. of tetrads 0 5.6 10.0 2.9 11.1 16.1 11.1
Rhytidiadelphus triquetrus 1 10 7 6 5 7 5 percent. of tetrads 1.9 13.9 17.5 17.6 18.5 22.6 18.5
Ulota bruchii records 1 24 27 23 20 26 19 percent. of tetrads 1.9 33.3 67.5 67.6 74.1 83.9 70.4
Ulota crispa s. str. 0 11 9 11 7 9 8 percent. of tetrads 0 15.3 22.5 32.4 25.9 29.0 29.6
data too irregularly distributed to categorise species: Cephaloziella massalongi† 1 0 1 0 2 4 7 percent. of tetrads 1.9 0 2.5 0 7.4 12.9 25.9
Cephaloziella nicholsonii† 0 3 2 2 2 9 8 percent. of tetrads 0 4.2 5.0 5.9 7.4 29.0 29.6
Isothecium alopecuroides† 0 15 3 10 4 2 2 percent. of tetrads 0 20.8 7.5 29.4 14.8 6.5 7.4
Plagiomnium affine† 1 5 6 2 0 3 3 percent. of tetrads 1.9 6.9 15.0 5.9 0 9.7 11.1
Pleuridium subulatum† 1 3 1 3 0 2 6 percent. of tetrads 1.9 4.2 2.5 8.8 0 6.5 22.2
TABLE 3. Comparison of coast tolerance and salt-tolerance
categories. The definitions of coast tolerance
categories are set out in Table 1 and taxa are assigned to these
categories in Table 2. Generalised salt-tolerance categories given here
are based on direct observation of occurrence in saline sites in Cornwall
and the Isles of Scilly, i.e. association with halophytic phanerogams and
lichens, or evident exposure of occupied locations to sea
spray. obligate halophyte: found
only in obviously saline places; strongly halophytic: found
almost entirely (>99% of records) in obviously saline places;
weakly halophytic: recorded
often (>25% of records) in obviously saline places;
highly coast-tolerant: some
records in obviously saline places; low or moderate coast
tolerance: few or no
records in obviously saline places; intolerant of coasts: rarely or
never seen in exposed coastal sites; highly intolerant of
coasts: never seen in exposed coastal sites. |