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The Lichens ot Marettimo (Egadi lslands. Sicily) 261
aod 41.7 % of lhe lichens, terricolous species being and periods of fog. On the shrubs of the macchia
only 13.7 % of the total. Compared with the lichen there is a well-developed, heliophytic community
flora of the calcareous Tremiti Islands (NIMIS,
1985b), which, not exceeding 200m altitude, host with such species as Teloschtstes chrysophthalmus,
only 123 species, the flora of Marettimo is much Parmotrema reticulatum, Pyrrhospora quernea,
richer and much more interesting. Its d iversity Ramalina canariensis, R. lacera, R. pusilla, R.
resembles that of the island of Capraia, in the roesleri, R. subgeniculata, Xanthoria steineri.
Tuscan Archipelago, which has a similar altitudinal Locally, in wind-swept ridges subject to humid air
currents, or in more sheltered situations, Tomabea
range and a similar size, but is made up of siliceous scutellifera and Physcia clementei are abundant.
substrata : for Capraia NIMIS & al. (1990) have The rare, more or less isolated trees at middle
reported 301 species of Jichens. elevations host severa! widespread and common,
temperate species which are quite rare on the
The high diversity of the lichen flora of Marettimo island, as most spedes of Parmelia. Terricolous
is certainly due to three main facto rs : a) t he vegetation i.s best developed in this belt, where it is
relatively undisturbed environment, b) the generally quite rìch; besides spedes such as Catapyrenium
high air humidity, c) the relatively pronounced squamulosum, Cladonia joliacea, C. rangiformis,
altitudinal range. During the excursion we had to Col/ema tenax, Diploschistes muscorum, Psora
climb up several times through the steep slopes decipiens, Squamarina cartilaginea and Toninta
above Marettimo, from sea level to more than BOOm. aromatica, which are widespread throughout the
Already in the field, it was quite dear that lichens island, tbe following lichens are restricted to or have
allowed to subdivide this altitudinal gradient into their optimum at middle elevations : Gatapyrenium
ptlosellum, Fulgensia fulgida , F. subbracteata,
three main belts, each with a different climatic Gloeoheppia turgtda, P/actdìopsis ctnerascens,
situation and with a set of characteristic species : Polyblastia rouxiana, Tontnia albilabra, T. taurlca,
Squamarina concrescens, S. lentigera, 7be/ocarpon
a)Upland areas, from ca. 500 to BOOm. These are macchiae, Topelia rosea, Verrucarla geophila.
the most humid parts of the island, with frequent
stagnation of fog and with the last remnants of a c)Coastal area, from sea level to ca. 250m. This
well-developed woody vegetation. They have the belt is under the direct influence of the sea.
highest incidence of suboceanic species; the humid Epiphytic vegetation is less luxuriant, but many
woodland with Q. tlex, fully exposed to the coastal species occur on more or less shaded
frequent fogs, hosts a well-developed epiphytic
vegetation with such species as Degelia plumbea, calcareous rocks exposed to humid, salt-loaded
Dimerella lutea, Gyalecta derivata, Heterodermia winds. The epiphytic vegetation is less well
Jeucomelos, Lobaria pulmonaria, Nephroma
laevigatum, Pachyphiale carneo/a, Peltigera characterized ; cultivated trees near the village host,
collina, Strigula stigmate/la, Teloschistes flavicans, together with the common Dirina ceratoniae,
Thelotrema lepadinum, Usnea articulata, several widespread Xantborion species, which are
Zamenhofta coralloidea, Zamenhofta hibemica.
Epigaeic vegetation is mostly characterized by the otherwise rare on the island, whereas on the shrubs
local occurrence of thick mats of Cladonia ciliata f. of the macchia fruticose and foliose Jichens are
tenuis, C. mediterranea and C. subsquamosa; quite scarce. The shrubs, however, host some
species restricted to epilithic vegetation of upland interesting crustose species such as Arthothelium
areas are Asptcilia cheresina, Hymenelia similìs, sardoum, Lecanora rubicunda, Opegrapha
Strlgula porinoides, and dominant are endolithic ochrocincta, Thelenella modesta and Thelopsis
lichens such as species of Bagliettoa and, in more jlaveola. The most peculiar lichens of lowland areas
shaded situations, of Porina ; some decalcified rock are epilithic species bound to coastal environments ;
outcrops host a few normally silicicolous species besides the common and widespread Dirina
such as Haematomma ocbroleucum v. porphyrium, massiliensis, Lecanactis grumulosa and Roccella
Lecanora campestris, L. sulphurea, Ochrolechia phycopsis we find such species as Arthonta
parella, Tephromela atra v. cypria. meridionalis, Calop/aca marina, C. ora, C.
thamnoblasta, Dirina cyclosora, Jngaderia
b)Intermediate belt, from ca. 250 to 500m. This troglodytica, Lecanora lisbonensis, Opegrapha
narrow belt is certainly less humid, and devoid of durleui, O. mougeotii, Petractts luetkemuellerl and
Thelopsis istaca, mostly occurring on shaded ,
well-developed woody stands ; the lichen flora steeply inclined calcareous rocks, and the two
suggests an alternation between dry, sunny periods,
Hommage scientifique à G. Clauzade
