Isoëtes todaroana (Isoëtaceae, Lycopodiophyta), a New Species from Sicily (Italy)

2009·3 MB·English

by  Angelo Troia

New
todaroana
Isoetes
(Isoetaceae, Lycopodiophyta),
a
from
Species
Sicily
(Italy)
Angelo
Troia* and Francesco M. Raimondo
Dipartimento
di Scienze Botaniche dell'Universita, via Archirafi 38, 1-90123 Palermo,
Italy
Four
species of Isoetes have been previously reported from
Sicily
(Troia,
2005): Isoetes histrix Bory, sicula Tod. [= subinermis &
(Bory) Cesca
/.
/.
=?
gymnocarpa
Peruzzi,
(Gennari) A. Braun], velata A. Braun. and
7. duriei
I.
I.
Bory. All of these grow on seasonally wet, siliceous except
soils, for velata
/.
which
colonizes temporary ponds.
Over
the last ten years, field, herbarium, and laboratory studies have been
conducted by one on Romeo
of us the genus
Isoetes and
(e.g., et 2000; Troia
al.,
As
Bellini, 2001; Troia,
2005). part of these studies, a population was
oi Isoetes
located wetland Mazara
in a near
del Vallo, Western Sicily. Closer inspection
of the specimens showed
they
that differed in several aspects from the other
species occurring on
the island. Analyses of living and dried plants confirmed
that this population represents a unique and previously undescribed
species of
which named
Isoetes, is here and described. For description and nomenclature
of megaspores and microspores we
followed Hickey and Musselman
(1986)
(2003), respectively.
Isoetes todaroana Troia & Raimondo, TYPE.—
nov. ITALY.
sp.
Sicily:
contrada "Critazzo" near Mazara
del Vallo, 37 41'07"N, 12 37'05"E, 60
ca.
m
10 Apr. Angelo
a.s.L, 2009, Troia (holotype: PAL; PAL,
isotypes:
FI).
1-10.
Figs.
Herba
perennis amphibia, emergens aut submersa. Cormus
trilobus,
radicibus dichotomis. 15-30 cm
Folia (-40), erecta vel patentia, 3-6 (-14)
longa, inferne brevi tractu anguste alato-membranacea, usque 3-4 mm,
basi
in
mm
medio
Duae magnae
circa lacunae 1-3
1 lata. et fasciculi fibrarum
periphaerici (collenchymatosi) in trasversali sectione. Stomata 37-
elliptica,
^m
24-32
70 ^im longa, tantum Velum
lata, in facie abaxiali obvia. sporangium
TROIA RAIMONDO: TODAROANA, A NEW FROM
& ISOETES SPECIES
SICILY
1-3. Morphologic!
Figs.
on
the
left partially cove:
obtegens. Ligula membranacea, Labium
lanceolata, basi auriculata. breve.
Squamae
paucae,
coriaceae, nigrescentes, lobis lateralibus rotundatis dente
et
medio
aciculari. Macrosporae candidae, sphaeroideae, 420-460 ^m, annulo
horizontali cinctae, hemispherio superiore undique
tricostatae, tuberculatae.
Microsporae hyeme
ovatae, ca. 25 ^im longae, aculeatae. Habitat in humidis
inundatis.
Plants amphibious, emergent or submerged in temporary ponds, losing their
summer
Stem
leaves in the dry season. (corm) with dichotomous
trilobate,
cm
roots. Leaves 15-30{-40), patent to erect, narrowly lanceolate, 3-6 (-14)
mm mm
3-4 wide wide
long, at base, ca. 1 at mid-length. Alae proximally
mm
hyaline or transluscent, ca.l wide the sporangium, gradually narrowing
at
Subula
distally. semiterete, adaxially abaxially convex. Leaf epidermis
flat,
with
cuticular ornamentation, "cuticular pegs" (sensu Prada and Rolleri, 2005,
=
"cuilas cuticulares" sensu and
Rolleri Prada, 2007) well developed, evident
as continuous longitudinal Stomatal complexes 37-
ridges. rows,
in
elliptic,
nm
24-32
70 long, |im wide, confined to the abaxial surface. Hypodermal
coUenchymatous
bands one to three, the two marginal bands sometimes
absent. Air chambers two, with translacunar diaphragms. Velum
complete.
mm
Ligule membranaceous,
ca. 1 long, broadly lanceolate, auriculate at base.

TROIA & RAIMONDO: ISOETES TODAROANA, A NEW FROM
SPECIES
SICILY
mm
SEM ma
Figs. 7-10. images of todaroi megaspores and microspores. Proximal view
/. 7. of
megaspore. view
Equatorial of megas] Megaspore
8. pore. 9. (detail of a single tubercle). 10. Distal
new
Etymology.—
This
species dedicated
is to the Sicilian botanist Agostino
Todaro
(1818-1892), in recognition of his contribution to the pteridological
of
flora Sicily.
Ecology.—The
type temporary wetland
locality is a that dries out during the
summer. remnant
a of a wider wetland has been "reclaimed" and
It is that
converted to farming land that surrounds and encloses the type The
locality.
natural vegetation, although altered, well represented with mosaic
is a of
communities, with species such as Bolboschoenus maritimus
(L.) Palla,
Eleocharis palustris (L.) Roem. & Schult., Scirpus cernuus Vahl, Mentha
pulegium Oenantbe Lythrum Tamarix Homulea The
L., sp., sp., sp., sp., etc.
wetland
hosts the last remnants of a peculiar freshwater invertebrate fauna;
a
preliminary investigation has example,
led, for to the discovery of a small
population of the notostracan Lepidurus apus lubbocki
(Crustacea), a "living
was
fossil" that considered extinct in Sicily Marrone, pers. comm.).
(F.
The
wetland on
exists a peculiar geological substrate of calcareous
sandstones with on
a thin layer of clays top (hence the name,
local "Critazzo",
which pH
in Sicilian dialect refers to clays). The soil around the Isoetes
(determined electrometrically with two replicates from 20 of and
g soil
measured
in distilled water with a dilution ratio of 1: 2.5) was found to be
AMERICAN FERN VOLUME NUMBER
JOURNAL:
99 4
(2009)
As we
know,
basic, 8.5-8.9. far as the other species occurring in Sicily
grow on
consistently acid soils, so that this although geologically
site,
complex, unusual,
is a fact that deserves further investigations.
known
Distribution.—/soefes todaroana only so far from the locus classicus.
is
in an area of about 200 X 100 m. possible that other populations may be
It is
found and
in the future, in Sicily elsewhere in the Mediterranean
area.
—
The known
Conservation Status. single population threatened by farming
is
human
and other activities (waste dumping, land reclamation, summer
fires,
On
"lUCN Red and
etc.). the basis of the current List Categories Criteria"
(lUCN, 2001], the species rated "Critically Endangered" [CR
is Blab(iii)].
Urgent measures needed
are to protect the considering that
site;
is
it
practically unexplored, possible that other rare or endangered species are
it is
present, in addition to Isoetes todaroana and Lepidurus apus lubbocki already
mentioned. However,
and
clear that a strategic area for migrating birds
it is it is
communities
hosts that can be referred to the habitat "Mediterranean
it
temporary pond", considered a "priority" habitat by the Council of the
European Communities 92/43/EEC Our
Directive. proposal include the
to
is
Community
site, currently not protected, inside the adjacent "Site of Interest"
code ITA010014, and
established to protect habitat species according to the
mentioned made
Directive. Since this inclusion will not be in a short time and
we
will not automatically guarantee the protection of species and habitats, also
suggest considering other actions agreements with the owners,
(e.g., territory
planning land purchase) soon
restrictions, as as possible.
—
Taxonomic Observations. The shape and
of the scales, particularly the
presence of only two leaf air chambers rather than four as in other species
all
of the genus (Rolleri and Prada, 2007), are the main differentiating characters
of this species. Its systematic relationships are difficult to assess merely on the
basis of anatomy and morphology, owing and convergent
to parallel
morphological evolution in the genus (Hickey, 1986; Hoot et al, 2006; Bolin
The
et al, 2008). presence of scales, sometimes transitioning into phyllopodia,
and coUenchymatous
between and
strands suggests a link this species the
Mediterranean and megaspore
"terrestrial" taxa, the ornamentation, in
particular, vaguely suggests a connection with histrix and sicula. However,
/. /.
shown
as by Bolin et al. (2008), the latter two species, although morpholog-
On
ically similar, are not immediately related. the other hand, the
fibrillose
megaspore background
surface suggests a relationship with other
(Fig.
9)
amphibious
species, the Isoetes velata.
e.g.,
new
Further studies are in progress to add to the knowledge of the species
and shed on
light relationships.
its
TROIA & RAIMONDO: ISOETES TODAROANA, A NEW FROM
SPECIES
SICILY