Lichen communities in the British Isles: A preliminary conspectus

348 P. W. James, f). L. Jlawkszoorth and F. Rose
Mediterranean association anc{ thus it is not surprising
British
to note
Isles, it
that,
appears in
to
thc
be most fr.q,,.rrt i., ,o.rtt
Barkman
n.gf^"a.^,Cf
regarded physcia though
clementei;; ;; ".rl
association, ".o--'niii.. i".r"ai.f il' .il:i"'J"il .,"#r,;ffil^"t
seem sufficiently distinctive to 'r,arrint treatment as a distinct association,
the T elo s c his t etum fl aztic antrc.
Teloschistetum flavicantis ass. nov. (Table VII)
This previously unrecognized association recalrs,
prove
and
to
may
be
e'entually
identical to, ,
Barkman's (1958) unnamed southern
and montane-Mediterranean Atlantic
variant oi the physcietunt
ascendezlzs
physciosum subass.
leptaleae Klem. which h. .on.iJ"r.i to o..,r,
Fontainebleau, provencc i., n.ir,urry, ,.,.r.
and the centrar Atlas Mountains.
is
The
closely
association
allied to the physuetu* nrrurdrn* o,r, is differentli.il.i*u.ity
by the abundance of reLschist r .p..i..
in 1i. ;;,:r:;";;;;;;;;;;::i'. zsiilosu.r
France; usually only ?. yor.irars iri-nr;t^1,-r;. physcia clementei, p.
Species
Anaptychia ciliaris
A. fusca
Eoernia l>runastri
Ochrolechia parella
O. yasudae
Parmelia caperata
P. perlata
Tesrn VII.
T elo s c hrLs t e tum fl.aoic antis ass. nov.
Stands
72
Additional species present in this community in
areas of the quadrats were : Bucllia , ,rrr",rr."'L
Leridea '":
eucrn(:n. Lphvnvin .n-)-t.,,.:- ,^ ,'
t l;"i,);::?"
.I
2
+ +
J
J
l
2
;-t
4
Species Stands
Parmelia subaurifera
P. subrudecta
P. sulcata
Ramalina farinacea
R. fastigiata
Teloschistes flaaicans
Bryophyta
t2
2a
-t
3+
-f
33
.'t -
+5
icombe.House (201811417): mature Acer pseutto-
87o/o, 11 A .diam' r'ncl' B5', aspect 2g0", 20 x 20-.-, "or,.,
2. S. Devon, s,_Widd.icombe House (201g11417): mature Ace.r pseudoplat.nus
in pasture, 40 cm diam, i".1. gt-,;rp; ct265.,,20 x 20cm, cover 90(1,,,
I I August 1973, D.L.H. ; typc rtrord."
-L
lij:
10. Lichen Communities in the British Isles 3+9
leptalea and P. tribacioides, which can form extensive stands in the sunniest
and driest parts of southern England, are very closely associated with it.
This community appears to have been formerly widespread in southcrn
England but is nor'v largely restricted to thc south-west (where it is now
much rarer than it u'as last century) from Dorset to Cornwall and is more
rarely found in Pembrokeshire (S. Wales). The twig facies (with ?.
chrysophthalmas) is still common in the Mediterranean area and in southwest
France (frorn southern Brittany southwards), where it is largely
found on twigs in very well lit situations. In south-west England today it
occurs both on twigs and on u-ell lit, well ventilated nutrient-enriched
tree trunks, but ?. chrysophthalmus seems now to be extinct in Britain
outside the Channel Islands (Hawksworth et al., 1974).
This community is not identical to the Teloschistetum chrysophthalmae
Ochsn. (see p. 344), the type record of which lacked any Teloschistes
species and is referable to the Physcietum ascendentis.
IV. Limestone Cornmunities
Hard limestones (e.g. Carboniferous and Devonian) support several
distinct lichen communities in the British Islcs. Most of these are able to
spread on to softer calcareous rocks ancl a wide range of basic man-made
substrates (e.g. asbestos-cement, concrete, basic brickwork and mortar),
but then occur esscntially as species-poor variants.
The communities developed on coastal limestones are essentially
species-poor facies of associations of inland limestone rocks and so are not
recognized separately here. Some elements of the Caloplacetum marinae
and Verrucarietum maurae, normally well developcd on siliceous rocks,
may be encountered on hard coastal limestones, e.g. marine Caloplaca,
Verrucaria and rarely Lichina species (see Fletcher, 197-5b). Arthol>yrenia
halodytes can also occur on softer limestones and chalk as well as its more
usual habitat of barnaclcs and other intertidal mollusc shells.
Species on soil and humus in crevices, soil and turf around limestone,
chalk, pebbles etc., are treated separately on pp. 393 +07, while intermediate
communities on other basic rocks are discussed on pp. 361-36+.
All. 12. Aspicilion calcareae
Aspicilion calcareae (Alberts.) comb. nov.-l,ecanoriort calcareae Alberts., Acta
phytogeogr. suec. 20, 3+ (1946), trasionym.-Caloplacion decipientis Klem., Ber.
bayer. bot. Ges. 28, 263 (1950).-Gyalection cupularis Matt., Bol. |b. 75, +20