New distributional records of non-native vascular plants in northern Italy

Abstract

New distributional records of non-native vascular plants are provided for the Italian regions Piemonte, Lombardia and Emilia- Romagna. Panicum barbipulvinatum is reported for the first time from Italy.

Full text

Natural History Sciences. Atti Soc. it. Sci. nat. Museo civ. Stor. nat. Milano, 2 (1): 5-14, 2015 DOI: 10.4081/nhs.2015.219
New distributional records of non-native vascular plants in
northern Italy
Filip Verloove1*, Nicola M. G. Ardenghi2
assess the exact identity of newly detected and already
present invaders.
With that purpose the rst author visited in September
2014 riparian habitats in the plain of river Po and its many
tributaries, primarily in order to improve the knowledge
on Cyperus in northern Italy (Verloove, 2014; Verloove
& Saiani, 2015). This scientic mission ts in COST Ac-
tion TD1209 ‘European Information System for Alien
Species’ (http://www.cost.eu/COST_Actions/fa/Actions/
TD1209, retrieved on December 2014) and facilitates
enhanced knowledge gathering and sharing through a
network of experts, providing support to a European IAS
information system. This, in turn, enables effective and
informed decision-making in relation to IAS. On that oc-
casion he was hosted by the University of Pavia where,
in collaboration with the second author, eld work was
performed, among others, in the region Lombardia.
In the present paper new distributional records for the
Italian regions Piemonte, Lombardia and Emilia-Romagna
are presented for sixteen non-native species of vascular
plants (others than Cyperus). One species, Panicum barbi-
pulvinatum Nash, is reported for the rst time from Italy.
MATERIALS AND METHODS
The taxa are arranged in alphabetical order. Each entry
includes the currently accepted name of the taxon and the
family to which it belongs (according to APG III, 2009), its
status and distribution in Italy (following Celesti-Grapow
et al., 2009a, 2009b), data from the herbarium label (for
acronyms see Thiers, 2014 onwards) and additional notes
about its native and secondary distribution area, invasive
behavior, ecology and, if relevant, identication aids and
taxonomical and nomenclatural comments.
Original photographs are provided for some of the taxa.
RESULTS
Amaranthus palmeri S.Watson, Proc. Amer. Acad. Arts,
12: 274. 1877.
(Amaranthaceae)
Naturalized neophyte new to the ora of Piemonte
(Conti et al., 2005; Celesti-Grapow et al., 2009a; Iamoni-
co et al., 2015; Iamonico, 2015).
Abstract - New distributional records of non-native vascular plants
are provided for the Italian regions Piemonte, Lombardia and Emilia-
Romagna. Panicum barbipulvinatum is reported for the rst time from
Italy.
Key words: alien plants, distribution, Italy.
Riassunto - Nuove segnalazioni di piante vascolari alloctone per
l’Italia settentrionale. Vengono forniti nuovi dati distributivi relativi ad
alcune specie esotiche per le regioni Piemonte, Lombardia ed Emilia-
Romagna. Panicum barbipulvinatum viene segnalato per la prima volta
in Italia.
Parole chiave: distribuzione, Italia, piante alloctone.
INTRODUCTION
Invasive Alien Species (IAS) threaten biodiversity,
society, human-health, well-being and economy. The an-
nual economic impact to Europe is estimated € 12.5 to
20 billion. Prompt detection of new invasive species as
well as their correct taxonomic identication is widely
considered to be of the utmost importance (Genovesi et
al., 2010). Although the non-native, potentially invasive
ora of Italy received a lot of attention in recent years
(e.g. Celesti-Grapow et al., 2009a, b; Celesti-Grapow et
al., 2010), and the knowledge evolved accordingly, the
work is never accomplished and updates are constantly
required (see e.g. Ardenghi et al., 2014). In our globalized
world the inux of new alien species seems to be innite.
Also, the taxonomic knowledge of researchers and eld
workers constantly improves which enable them to better
1 Botanic Garden of Meise, Nieuwelaan 38, B-1860 Meise,
Belgium
2 Department of Earth and Environmental Sciences, University
of Pavia, Via S. Epifanio 14, I-27100 Pavia, Italy
E.mail: sahfen@hotmail.com
* Corresponding author: lip.verloove@br.fgov.be
© 2015 Filip Verloove, Nicola M. G. Ardenghi
Received: 10th January 2015
Accepted for publication: 19th April 2015

6
ITALY. Piemonte. Prov. Alessandria: Tortona, river
Scrivia at railway bridge, gravelly riverbed, locally, along
with A. tuberculatus, 09.09.2014, F. Verloove 11206
(BR).
A native of the southwestern U.S.A. and Mexico,
Amaranthus palmeri now occurs as a weed in Europe,
Asia and Australia (Mosyakin & Robertson, 2003). In
Italy it was recently discovered in Emilia-Romagna, in
the province of Ravenna (Iamonico et al. 2015; Iamon-
ico, 2015). While for many decades it remained strictly
casual in Europe (often associated with imported cereals
or soybeans; e.g. Verloove & Vandenberghe, 1993), it
managed to naturalize locally in recent times, especially
in the Mediterranean area. In Spain naturalized popula-
tions were detected around Lleida in 2007 (Verloove &
Sánchez Gullón, 2008) and soon afterwards it proved to
have become a troublesome agricultural weed in maize
elds there (Recasens et al., 2013). Elsewhere in the
Mediterranean area stable populations are known from
Israel and Greece (Raus & Raabe, 2006). In Ravenna
province the plant was regarded as casual (Iamonico
et al., 2015; Iamonico, 2015), even though the species
was conrmed for at least two years consecutively in
the same site (see http://www.actaplantarum.org/o-
raitaliae/viewtopic.php?f=106&t=67866, retrieved on
December 2014); in Tortona the population is clearly
naturalized.
Amaranthus palmeri is a dioecious species. In Ita-
ly a related species, A. tuberculatus (Moq.) J.D.Sauer,
has been known since 1975 (Soldano, 1982). It now
has become an invasive species in riparian habitats
and cultivated fields (Banfi & Galasso, 2010), espe-
cially in the plain of river Po and its tributaries. Since
A. palmeri is equally aggressive and occurs in the
same type of habitats, similar behavior is predictable.
Both species are rather alike and may have been con-
fused. A. palmeri has much longer bracts and tepals,
the inflorescence therefore being stiff and prickly in
appearance. In Tortona, along Scrivia river, both grow
sympatrically.
Bidens connatus Muhl. ex Willd., Sp. Pl., ed. 4
[Willdenow], 3 (3): 1718 (-1719). 1803. [Fig. 1]
(Asteraceae)
Naturalized neophyte new to the ora of Piemonte
(Conti et al., 2005; Celesti-Grapow et al., 2009a; Ban
& Galasso, 2010).
ITALY. Piemonte. Prov. Alessandria: Villanova Mon-
ferrato, W of motorway E25, rice elds, 12.09.2014, F.
Verloove 11101 (BR).
Bidens connatus is originally native in North America
but known as a more or less widely naturalized xenophyte
in Europe (e.g. Schumacher, 1941; Debray, 1963). In Ita-
ly it was known so far from Lombardia, Emilia-Romagna,
Friuli-Venezia Giulia, Marche and Veneto, either as a
casual, naturalized or invasive alien (Celesti-Grapow et
al., 2009a; Ardenghi, 2015).
In fact, its genuine distribution and degree of naturali-
zation should be critically reassessed, the species being
much reminiscent of native B. tripartitus L. It is best dis-
tinguished from the latter by leaves usually undivided and
cypselae 4-angled (not attened) with usually tuberculate
faces (Strother & Weedon, 2006).
In September 2014 Bidens connatus was recorded
on several occasions. In addition to the locality cited
above, it was also seen in Valenza, Bastida Pancarana,
Boretto, Ficarolo, Mezzano, Piacenza, Ravalle, San
Rocco al Porto and Viadana (all along river Po) and in
Serravalle Scrivia (along river Scrivia). It is obviously
much more widespread, rmly established but widely
overlooked.
It should be recalled that according to Art. 62.2(a) of
the International Code of Nomenclature (McNeill et al.,
2012), Bidens should be treated as a compound, “Bi-dens”,
the last word (dens, dentis) being male; then the specic
epithet should be “connatus” instead of “connata” (see
also next species). Even though initially recommended by
the Report of the Committee for Spermatophyta (Brum-
mitt, 2000), the proposal to conserve the name Bidens
with a conserved gender (Harriman, 1998), was nally
not upheld (McNeill et al., 2006, App. III) (Ban & Ga-
lasso, 2010).
Fig. 1 - Bidens connatus, Bastida Pancarana (PV), September 2014
(Photo: N. Ardenghi).
FILIP VERLOOVE, NICOLA M. G. ARDENGHI

7
Bidens vulgatus Greene, Pittonia, 4 (21): 72. 1899. [Fig.
2]
(Asteraceae)
Naturalized neophyte new to the ora of Lombardia
and Emilia-Romagna (Conti et al., 2005; Celesti-Grapow
et al., 2009a; Ban & Galasso, 2010).
ITALY. Lombardia. Prov. Cremona: Casal-
maggiore, river Po, damp track in woodland, lo-
cally frequent, 14.09.2014, F. Verloove 11090 (BR,
MSNM); Prov. Pavia: Gambolò, Cascina Portalupa
(UTM ED50: 32T 495784.5013034), margine di
sentiero in querco-carpineto, con Erigeron canaden-
sis, Prunella vulgaris, Glechoma hederacea, 73 m,
17.10.2014, N. Ardenghi, P. Cauzzi & S. Pedrini
(MSNM); Prov. Pavia: Stradella, San Zeno, sponda
destra del torrente Versa all’incirca all’altezza della
rotonda tra viale Resistenza e la SP201 (UTM ED50:
32T 524108.4989963), vigneto, 86 m, 18.10.2014,
N. Ardenghi (MSNM); Prov. Milano: Milano, stazi-
one FFSS di Milano-Rogoredo (UTM ED50: 32T
518642.5031188), aiuola, 109 m, 28.11.2014, N. Ar-
denghi (MSNM).
This is a widespread species in North America (Strother
& Weedon, 2006). Like the preceding, it is poorly known
and overlooked in Europe, although known since many
decades (e.g. Schumacher, 1941; Debray, 1963). Up to
present it was known in Italy only from Friuli-Venezia
Giulia (Celesti-Grapow et al., 2009a). Bidens vulgatus is
much reminiscent of B. frondosus L. but often more ro-
bust with larger ower heads and with a higher number of
calyculi (10-16 vs. usually 8).
In addition to the localities cited above, it was also
detected along river Po in Boretto (Emilia-Romagna). It
may have been widely overlooked elsewhere.
Cardamine hamiltonii G.Don, Gen. Hist., 1: 167.
1831.
≡ Cardamine debilis D.Don, Prodr. Fl. Nepal.: 201. 1825,
nom. illeg.
≡ Cardamine exuosa With. subsp. debilis O.E.Schulz,
Bot. Jahrb. Syst., 32 (4): 478. 1903.
(Brassicaceae)
Naturalized neophyte new to the ora of Piemonte
(Conti et al., 2005; Celesti-Grapow et al., 2009a; Ardeng-
hi & Mossini, 2014).
ITALY. Piemonte. Prov. Vercelli: Arborio, river Sesia
N of the bridge, exposed river bank, 06.09.2014, F. Ver-
loove 11043 (BR).
Cardamine hamiltonii is a poorly known but wide-
ly spread species in many parts of Europe. It has long
been confused with C. flexuosa but molecular data
have demonstrated that it is a distinct entity, appar-
ently native in East Asia (e.g. Lihová et al., 2006;
Bleeker et al., 2008). It is distinguished from the latter
by the absence at flowering of a distinct basal rosette
and the markedly trilobed leaflets that usually have a
glabrous upper leaf surface (cfr. Mansanet-Salvador
et al., 2015).
Fig. 2 - Bidens vulgatus, Martignana di Po (CR), September 2014 (Photo: F. Verloove).
NEW DISTRIBUTIONAL RECORDS OF NON-NATIVE VASCULAR PLANTS IN NORTHERN ITALY

8
Al-Shehbaz et al. (2010) referred to this taxon as Car-
damine exuosa subsp. debilis but agreed that it should be
recognized at species level and its correct name be sought.
In recent times it became clear that the name C. hamilto-
nii probably can be applied for these plants (e.g. Bomble,
2014; Ardenghi et al., 2015; Dirkse et al., 2015).
For Italy this species was recently reported for the rst
time from Lombardia and Toscana (Ardenghi & Mossini,
2014). In September 2014 it was seen in Arborio along-
side river Sesia (see above), in an area from where it had
been claimed before (Dienst, 2007). It was also seen as
an urban weed in Vercelli and in rice elds in Albano
Vercellese and Robbio. It is well-established, weedy and
doubtlessly widely overlooked elsewhere in Italy.
Cucurbita maxima Duchesne, Essai Hist. Nat. Courges:
7. 1786.
(Cucurbitaceae)
Conrmation of casual neophyte for the ora of Pie-
monte (Conti et al., 2005; Celesti-Grapow et al., 2009a).
ITALY. Piemonte. Prov. Vercelli: Vercelli, city cent-
er close to river Sesia, roadside, 07.09.2014, F. Verloove
11069 (BR).
Doubtlessly an ephemeral alien, this species unlike in
other parts of Europe, is frequently cultivated in northern
Italy, its fruits being used in different traditional dishes.
It is distinguished from the latter by its peduncle that is
terete and becoming corky in fruit. Its leaves are almost
entire or very shallowly lobed and softly hairy above. C.
pepo, in contrast, has peduncles that are deeply furrowed
in fruit (conspicuously angled, not corky) and its leaves
are deeply 5-lobed and hirsute hairy above.
Cucurbita maxima was considered doubtful for Pie-
monte by Conti et al. (2005) and not listed from that re-
gion by Celesti-Grapow et al. (2009a).
Digitaria violascens Link, Hort. Berol. [Link], 1: 229.
1827.
(Poaceae)
Naturalized neophyte new to the ora of the province
of Alessandria (Piemonte) (Verloove et al., 2011).
ITALY. Piemonte. Prov. Alessandria: Valenza, river
Po S of the bridge, sandy river bank, 07.09.2014, F. Ver-
loove 11088 (BR).
A native from the Old World tropics Digitaria violas-
cens has long been overlooked in southern Europe. Ver-
loove (2008) cited records from France and Italy (prov.
Novara in Piemonte), subsequently also from Spain (Ver-
loove & Sánchez Gullón, 2008). Later, it turned out to be
much more widespread in northwestern Italy (Verloove
et al., 2011). In Piemonte it was previously recorded in
the provinces Biella, Torino, Verbano-Cusio-Ossola and
Vercelli (Verloove et al., 2011) and in September 2014 it
was also seen along river Po near Valenza, apparently for
the rst time in the province of Alessandria.
Muhlenbergia frondosa (Poir.) Fernald, Rhodora, 45
(534): 235. 1943.
(Poaceae)
Naturalized neophyte new to the ora of Emilia-Ro-
magna (Conti et al., 2005; Celesti-Grapow et al., 2009a).
ITALY. Emilia-Romagna. Prov. Reggio
nell’Emilia: Boretto, river Po E of the bridge, ripar-
ian woodland, locally, 13.09.2014, F. Verloove 11000
(BR, MSNM).
Muhlenbergia frondosa is a native species in south-
ern Canada and the contiguous U.S.A. (Peterson, 2003).
It is only rarely seen outside of its native distribution
range. However, in Italy it is known since several dec-
ades from Piemonte (Soldano, 1977) where it is natural-
ized, for instance in riparian woodland alongside river
Sesia. In recent years it seems to spread in northern
Italy: Bertolli & Prosser (2013) reported about its dis-
covery in Trentino-Alto Adige and in September 2014
it was also detected alongside river Po in Boretto. This
species is rather inconspicuous and often very reluctant
to ower; it may be more widespread but overlooked.
Oenothera pedemontana Soldano, Rivista Piemont.
Storia Nat., 4: 131. 1983. [Fig. 3]
(Onagraceae)
Naturalized neophyte new to the ora of Lombar-
dia (Soldano, 1983; Soldano, 1993; Ban & Galasso,
2010).
ITALY. Lombardia. Prov. Pavia: Bereguardo, river
Ticino close to the bridge, sandy river bank, 11.09.2014,
F. Verloove 11016 (BR).
This microspecies from the Oenothera biennis aggre-
gate (possibly a hybrid of the latter; Dietrich et al., 1997)
was originally described from Piemonte, the type being
from Saluggia in Torino province (Soldano, 1983). It is
now more or less widely dispersed in Piemonte (see map
in Cecere et al., 2012) but had never been recorded out-
side of this region (Conti et al., 2005; Celesti-Grapow et
al., 2009a). In September 2014 this species was found
growing in abundance on the sandy banks of river Ticino
in Bereguardo.
Characteristic features of Oenothera pedemontana
are its tall habit (stem up to 230 cm long), late ower-
ing, presence of glandular hairs on the hypanthium, petals
wider than long (ca. 26×17-23 mm) and relatively small
capsules ca. 18-33 mm long with emarginate capsule teeth
(e.g. Soldano, 1993).
Panicum barbipulvinatum Nash, Mem. New York Bot.
Gard., 1: 21. 1900.
= P. riparium H.Scholz, Feddes Repert., 113 (3-4): 275.
2002.
(Poaceae)
Naturalized neophyte new to the ora of Italy (Piemon-
te) (Conti et al., 2005; Celesti-Grapow et al., 2009a).
ITALY. Piemonte. Prov. Alessandria: Valenza, riv-
er Po S of the bridge, sandy river bank, very common,
07.09.2014, F. Verloove 11060 (BR); Prov. Alessandria:
Arquata Scrivia, river Scrivia N of the bridge, gravel-
ly river bed, frequent, 09.09.2014, F. Verloove 11062
(BR).
Panicum barbipulvinatum is an enigmatic species
originating in temperate North America. Its taxonomic
status is debated: in its area of origin it is merely included
in the variability of P. capillare L. by modern authors (e.g.
Freckmann & Lelong, 2003). In Europe, however, where
FILIP VERLOOVE, NICOLA M. G. ARDENGHI

9
only part of the genetic diversity of the latter is present,
it is easily distinguished. This inspired Scholz (2002) to
describe it as a neo-endemic species new to science, P.
riparium. Recently, Amarell (2013) demonstrated that
Scholz’ new species in fact perfectly corresponds with the
American P. barbipulvinatum. Moreover, he advocated,
like Scholz, that this taxon should be accepted at species
rank (as is, for instance, P. hillmanii Chase from the same
species complex). His point of view was followed in the
recently published Flora Gallica (Tison & de Foucault,
2014).
Panicum barbipulvinatum has a laxer inorescence
with spikelets on short pedicels that are tightly appressed.
The narrower spikelets are long-acuminate at apex. This
particular combination of features renders the plant a
characteristic jizz that is fairly different from that of P.
capillare.
In September 2014 Panicum barbipulvinatum was
seen on several occasions in Piemonte, always on ex-
posed sandy or gravelly banks of rivers Po and Scriv-
ia.
Panicum philadelphicum Bernh. ex Trin., Gram. Panic.
[Trinius]: 216. 1826.
= Panicum gattingeri Nash, Fl. S.E. U.S. [Small], 92
(1327). 1903.
(Poaceae)
Conrmation of naturalized neophyte for the ora of
the province of Alessandria (Piemonte) (Soldano & Ver-
loove, 2007).
Fig. 3 - Oenothera pedemontana, Bereguardo (PV), September 2014 (Photo: N. Ardenghi).
NEW DISTRIBUTIONAL RECORDS OF NON-NATIVE VASCULAR PLANTS IN NORTHERN ITALY

10
ITALY. Piemonte. Prov. Alessandria: Valenza, river
Po S of the bridge, sandy river bank, few individuals,
07.09.2014, F. Verloove 10990 (BR).
This North American species was only known from
a single, historical record in Alessandria province (Sol-
dano & Verloove, 2007). Its present-day presence is here
conrmed. In Piemonte, it is also known from Torino
province (Verloove & Selvaggi, 2011), also along river
Po.
Panicum philadelphicum is much reminiscent of P.
capillare and both possibly have been confused in parts
of Europe. It is readily distinguished by its panicles that
are only ca. 1/3 the total height of the plant, the base
of the peduncle that is not breaking at maturity and the
slightly smaller spikelets that are acute at apex, not acu-
minate.
Perilla frutescens (L.) Britton, Mem. Torrey Bot. Club, 5
(18): 277. 1894. [Fig. 4]
(Lamiaceae)
Casual neophyte new for the ora of Piemonte (Conti
et al., 2005; Celesti Grapow et al., 2009a).
ITALY. Piemonte. Prov. Alessandria: Basaluzzo, tor-
rente Lemme close to SP 160, gravelly riverbed, 4 indi-
viduals, 08.09.2014, F. Verloove 11085 (BR).
Perilla frutescens from Asia is widely cultivated as an
ornamental or as an oilseed crop. Up to present it has been
recorded in Italy in Lombardia and Veneto, always as a
casual alien (Celesti-Grapow et al., 2009a). It is here re-
ported for the rst time from Piemonte. In addition to the
locality cited above, it was also seen in Arquata Scrivia
along river Scrivia. It does not seem to naturalize (yet).
Persicaria pensylvanica (L.) M.Gómez, Anales Inst.
Segunda Enseñ., 2: 278. 1896.
(Polygonaceae)
Naturalized neophyte new for the ora of the province
of Mantova (Lombardia) (Ban & Galasso, 2010).
ITALY. Lombardia. Prov. Mantova: Viadana, river Po
W of the bridge, sandy river bank, few plants, 15.09.2014,
F. Verloove 11058 (BR).
A native of North America, this species became natu-
ralized in Europe, especially in riparian habitats. In Italy it
is known from the northernmost regions (Celesti-Grapow
et al., 2009a). It is here reported for the rst time from
Mantova province in Lombardia.
Fig. 4 - Perilla frutescens, Basaluzzo (AL), September 2014 (Photo: F. Verloove).
FILIP VERLOOVE, NICOLA M. G. ARDENGHI

11
This species is obviously naturalized along river Po
but usually occurs in small populations. It does not seem
to be an aggressive invader.
Populus deltoides W.Bartram ex Marshall, Arbust. Amer.:
106. 1785. [Fig 5]
(Salicaceae)
Casual neophyte new to the ora of the province of
Lodi (Lombardia) (Ban & Galasso, 2010).
ITALY. Lombardia. Prov. Lodi: San Rocco al Porto,
river Po W of the bridge, river bank, several young, self-
sown trees, 13.09.2014, F. Verloove 11059 (BR).
This North American native is widely planted in
Europe, although much less so than P. ×canadensis
Moench (pro sp.), its hybrid with native P. nigra L. It
is reported to be an exceptional escape from cultivation
in Lombardia, only being known from three localities
in the Pavia area since 1905 (Ban & Galasso, 2010;
Ardenghi, 2013). In San Rocco al Porto several young,
obviously self-sown trees were seen on the sandy banks
of river Po.
Populus deltoides is a distinct species with leaves up to
18 cm long or even longer, provided with more prominent
and hooked marginal teeth. These features distinguish it
from juvenile individuals of P. ×canadensis, which usu-
ally bear leaves larger than those of the adult trees (see
Eckenwalder, 2010).
Rotala ramosior (L.) Koehne, Fl. Bras. (Martius), 13 (2):
194. 1877.
(Lythraceae)
Naturalized neophyte new to the ora of the prov-
ince of Alessandria (Piemonte) (Celesti Grapow et al.,
2009a).
ITALY. Piemonte. Prov. Alessandria: Villanova Mon-
ferrato, rice elds, 12.09.2014, F. Verloove 11079 (BR).
Rotala ramosior originally is an American species but
it occurs in the Old World as a weed of rice elds, for in-
stance in Italy and the Philippines (Cook, 1979). In Italy
it was rst discovered in Piemonte in 1972 (Cook, 1973),
subsequently also in Lombardia (Ban & Galasso, 2010).
In the past decades it has repeatedly been conrmed from
Piemonte (e.g. Soldano, 1977; Abbà, 1980; Varalda et
al., 1984; Desfayes, 2005) but it seemed to be conned to
the province of Vercelli, from where it was originally re-
ported by Cook (1973). In September 2014 it was found,
apparently for the rst time, in the province of Alessan-
dria. It was found growing in quantity, with Ammannia
coccinea Rottb. and other weeds, in a rice eld near Vil-
lanova Monferrato.
Fig. 5 - Populus deltoides, San Rocco al Porto (LO), September 2014 (Photo: F. Verloove).
NEW DISTRIBUTIONAL RECORDS OF NON-NATIVE VASCULAR PLANTS IN NORTHERN ITALY

12
Symphyotrichum pilosum (Willd.) G.L.Nesom var.
pringlei (A.Gray) G.L.Nesom, Phytologia, 77 (1994, 3):
289. 1995.
(Asteraceae)
Naturalized neophyte new to the ora of Piemonte
(Conti et al., 2005; Celesti-Grapow et al., 2009a).
ITALY. Piemonte. Prov. Vercelli: Ghislarengo, ca.
1.5 km SW of the village, abandoned gravel pit, common,
06.09.2014, F. Verloove 10985 (BR, MSNM).
Symphyotrichum pilosum is native in eastern North
America (Brouillet et al., 2006) but widely cultivated as
an ornamental in Europe. It is a poorly known species that
has been confused with S. ericoides (L.) G.L.Nesom, S.
lateriorum (L.) Á.Löve & D.Löve and even S. lanceo-
latum (Willd.) G.L.Nesom. Italian claims of the rst two
species are mostly erroneous and referable to S. pilosum
(Ban & Galasso, 2010). The latter is fairly characteris-
tic in having pedicels with numerous linear to subulate
bracts and phyllaries with acute, spinulose apices. Stems
and leaves may be either pilose to hirsute (var. pilosum)
or glabrous (var. pringlei).
In Italy Symphyotrichum pilosum was only known
with certainty from Lombardia (Ban & Galasso, 2010)
although it may have been overlooked elsewhere. In
Ghislarengo it has invaded rough ground in an abandoned
quarry. It looks perfectly established there.
Symphyotrichum squamatum (Spreng.) G.L.Nesom,
Phytologia, 77 (1994, 3): 292. 1995.
(Asteraceae)
Naturalized neophyte new to the ora of the province
of Alessandria (Piemonte) (Pistarino et al., 1999).
ITALY. Piemonte. Prov. Alessandria: Tortona, bridge
over river Scrivia, at entrance of A7 motorway, rough,
bare ground, 09.09.2014, F. Verloove 11037 (BR).
This South American species is fast spreading and
considered invasive in large parts of the Mediterranean
area, including Italy (Celesti-Grapow et al., 2009a). In the
Piemonte region it was known from Torino and Cuneo
provinces (Pistarino et al., 1999) but not yet from Ales-
sandria.
Acknowledgements
Daniela Bouvet and Alberto Selvaggi (Torino) and
Gabriele Galasso (Milano) are acknowledged for check-
ing data from the Piemonte and Lombardia regions re-
spectively. John Strother (U.S.A.) and Jean-Marc Tison
(France) helped with the identication of Bidens vulgatus,
as did Adriano Soldano (Vercelli) for Oenothera pede-
montana. Maurizio Tabacchi (Vercelli) is thanked for his
assistance in rice elds in Piemonte. Finally, eld work
by the rst author in September 2014 was granted by
COST (Cooperation in Science and Technology), Action
TD1209.
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