Revue internationale d'écologie méditerranéenne International ...

Material and methods
Study species
Within the Genista genus, Genista lobelii
belongs to the section Erinacoides Spach.
(Gibbs, in Tutin et al. 1968) with other
species which are distributed predominantly
in the west Mediterranean mountainous areas.
In the past, G. lobelii was often confused with
related species through the whole western
Mediterranean area. In S-E France, G. lobelii
was initially described by De Candolle (in
Lamarck & De Candolle 1805) as distinct
species from the G. aspalathoides previously
described by Lamarck (1788) from N-W
Africa. Then Nyman (1878) combined
G. lobelii as variety of G. aspalathoides, and
French botanists often confuse and include
G. lobelii and G. salzmanii within
G. aspalathoides (see Bonnier & Douin 1911-
1935). Also, in N-W Italy, Corsica and Sardinia,
G. salzmanii initially described as distinct
species by De Candolle (1825) was often
confused with “G. lobelii auct.” (see Pignatti
1982), although Vierhapper (1919) had clearly
separated G. salzmanni DC from G. lobelii
DC and distinguished both these species from
G. aspalathoides Lam. In S-E Spain,
G. longipes was first described by Pau (1904)
as species rank, and then proposed as subspecies
of G. lobelii by Heywood (1958). In
S-E Spain, G. pumila, initially described as
variety of G. baetica, was elevated at species
rank by Vierhapper (1919) but still often confused
with “G. lobelii auct.” (see De Bolos &
Vigo 1984). In N-W Spain, G. legionensis,
initially described as variety of
G. aspalathoides in the first part of the
20th century, was elevated during the second
part of the century as separate species or as
subspecies of G. hystrix following various
taxonomic reviews (see Talavera 1999). Earlier
on, Maire (in Jahandiez & Maire 1932)
proposed Genista aspalathoides subsp. erinaceoides
from French plants which were in
taxonomical synonymy with G. lobelii (Heywood
1958).
According to Verlaque (1992), Genista lobelii
subsp. lobelii with 2n = 18 chromosomes is
restricted to the Basse Provence area (see also
Seidenbinder-Rondon 1989) and is different
from subsp. longipes as decribed by Heywood
(1958), present in S-E Spain and North
Africa, and having 2n = 18 or 2n = 36 chromosomes.
Moreover, Verlaque (1992) pro-
ecologia mediterranea – Vol. 36 (1) – 2010
Distribution, habitat and population size variation of Genista lobelii (Fabaceae)
from the calcareous mountains of Basse Provence (S-E France)
posed that G. lobelii from Basse Provence is
a triploïd species (x = 6, 2n = 3x = 18), a
hypothesis supported by observation of solitary
chromosomes, bivalents and trivalents
during the somatic ovary metaphase with
pollen sterility about 30% and pollen containing
n = 9 or n = 12 chromosomes. This is
an important observation because population
dynamics could be reduced by a partial individual
sterility or reduced fitness. Tetraploids
or hexaploids following Verlaque (1992) caryotypes
were never observed in subsp. lobelii
from Basse Provence region.
After these taxonomical issues, G. lobelii
stricto sensu (subsp. lobelii) is now considered
as an endemic species from the south
eastern France “Basse Provence” area in the
Bouches-du-Rhône and Var counties (Loisel
1976; Cruon 2008; Jauzein & Tison “in
press”).
Genista lobelii stricto sensu is a spiny hemispherical
shrub (10-30 cm) with a short and
woody main stem, intensively ramified. All
branches are small and apically spiny. Leaves
are entire, without stipule, very small (2-5 mm
long), deciduous, sessiles and with elliptic
obovate shape. Their upper surface is nearly
glabrous while the bottom part has sericeous
hairs. The flowers are singly or rarely paired,
with beautiful yellow corolla, short pedicels
(4-9 mm long) and small calyx (4-6 mm long)
with applied hairs. There are two bracteoles
on the floral peduncle. Legume fruits are short
(1-1.5 cm), with apical mucro, including 2-4
seeds.
Distribution and floristic data
In order to demarcate the geographical distribution
of G. lobelii, we compiled the available
data in the regional literature (Molinier
1934; Loisel 1976; Rebuffel 1998; Charles
2001) and unpublished data collected by local
actors (Conservatoire botanique national
méditerranéen de Porquerolles, ECO-MED
society). This was coupled with field investigations
carried out from 2006 to 2008 across
all Basse Provence mountains in potentially
suitable areas for G. lobelii. During field
investigations, two patches of individuals separated
by at least 100 meters for small population
(< 20 m 2 ) such as cap Canaille and by
500 meters for large population (> 100
hectare) such as Sainte-Victoire were
recorded as different stations. Surface area
occupied by G. lobelii was estimated in the
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