Euphorbia duvalii (Euphorbiaceae) in the Iberian Peninsula

Abstract

Euphorbia duvalii Lecoq & Lamotte is an endemic species from the Catalan-Occitan territory ―western Mediterranean area― and is usually found in the south of France. Euphorbia duvalii has been cited from some localities of the Iberian Peninsula, but in later reviews all of these citations were finally identified as other species of Euphorbia L. One of these citations, from the Alt Empordà ―Girona, Spain―, was of specific interest because not all the sources agreed on what the species was. To clarify whether or not this species is really present in the Iberian Peninsula, we examined new material from this population in order to establish whether the species is in fact E. duvalii. Once the morphology of the specimens from the Serra de Bac Grillera population had been analysed, we were able to confirm that they were indeed E. duvalii. This means that this is the only area on the Iberian Peninsula where this endemic species has been identified. The population is located in a rocky meadow that contains some scrub and is surrounded by pinewoods. Because this is the one and only Iberian population, a management and conservation plan needs to be drawn up to ensure its preservation.

Full text

Anales del Jardín Botánico de Madrid 75 (2): e073 https://doi.org/10.3989/ajbm.2495
ISSN: 0211-1322 anales@rjb.csic.es, http://rjb.revistas.csic.es/index.php/rjb
Copyright: © 2018 CSIC. This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial (by-nc)
Spain 3.0 License.
Euphorbia duvalii (Euphorbiaceae) in the Iberian Peninsula
Jordi Bou 1,* & Josep Bou i Tomàs 2
1 LAGP-Flora and Vegetation, Institute of the Environment, University of Girona, Campus Montilivi, 17071 Girona, Spain.
2 HGI, University of Girona, Campus Montilivi, 17071 Girona, Spain.
* Author for correspondence: jordi.bou.manobens@gmail.com, https://orcid.org/0000-0001-9454-8023
2 pistacia400@gmail.com, https://orcid.org/0000-0001-5043-5318
Abstract. Euphorbia duvalii Lecoq & Lamotte is an endemic species
from the Catalan-Occitan territory ―western Mediterranean area― and
is usually found in the south of France. Euphorbia duvalii has been cited
from some localities of the Iberian Peninsula, but in later reviews all of
these citations were nally identied as other species of Euphorbia L.
One of these citations, from the Alt Empordà ―Girona, Spain―, was of
specic interest because not all the sources agreed on what the species
was. To clarify whether or not this species is really present in the Iberian
Peninsula, we examined new material from this population in order to
establish whether the species is in fact E. duvalii. Once the morphology
of the specimens from the Serra de Bac Grillera population had been
analysed, we were able to conrm that they were indeed E. duvalii.
This means that this is the only area on the Iberian Peninsula where
this endemic species has been identied. The population is located in a
rocky meadow that contains some scrub and is surrounded by pinewoods.
Because this is the one and only Iberian population, a management and
conservation plan needs to be drawn up to ensure its preservation.
Resumen. Euphorbia duvalii Lecoq & Lamotte es una especie endémica
del territorio catalano-occitano ―área mediterránea occidental― que
puede ser hallada normalmente en el sur de Francia. Euphorbia duvalii
ha sido citada de algunas localidades de la Península Ibérica, pero en
revisiones posteriores todas las citas se identicaron nalmente como
otras especies de Euphorbia L. Una de estas citas, la del Alt Empordà
―Gerona, España―, era muy interesante, ya que no todas las fuentes
estaban de acuerdo a qué especie correspondía. Para claricar si esta
especie se encuentra en la Península Ibérica, examinamos material nuevo
de esta localidad para determinar si la especie era de hecho E. duvalii. Tras
el análisis de la morfología de los especímenes de la población de la sierra
de Bac Grillera, fuimos capaces de conrmar que se trataba de E. duvalli.
Esto signica que ésta es la única área en la península ibérica donde esta
especie endémica ha sido identicada. La población se encuentra en un
prado rocoso con algunos matorrales y rodeado de pinares. Ya que ésta es
la única población ibérica, es necesario un plan de gestión y conservación
de esta especie para su preservación.
Bou J. & Bou i Tomàs J. 2018. Euphorbia duvalii (Euphorbiaceae) in the Iberian Peninsula. Anales del Jardín Botánico de Madrid 75 (2): e073.
https://doi.org/10.3989/ajbm.2495.
Title in Spanish: Euphorbia duvalii Lecoq & Lamotte en la península ibérica.
Received: 18‒IV‒2018; accepted: 1‒X‒2018; published online: 19‒XI‒2018; Associate Editor: M. Velayos.
INTRODUCTION
Euphorbia duvalii Lecoq & Lamotte (Euphorbiaceae
Juss.) is an endemic plant from the Catalan-Occitan
territory, of which there are a few populations in the
southeast of France where the plants can be found in
the rocky calcicolous meadows in the Midi Mountains:
Causses des Cévennes, Causses du Quercy, Corbières, and
Pyrénées-Orientales in the departments of Ardèche, Aude,
Aveyron, Gard, Hérault and Lozère (Simon & Vicens
1999; Tison & al. 2014). However, in the Iberian Peninsula
it is known to have only one habitat in the northeast of
Catalonia, in the Alt Empordà, in the wilderness area of
the Alta Garrotxa (Bou i Tomàs 1985). Although there are
citations from the Serra del Boumort (Molero & al. 1988;
Pujadas 1981) and Montsec (Romo 1989), these would
appear in fact to be referring to E. dulcis L. (Simon &
Vicens 1999).
There have been several incidences of confusion about
the presence of this taxon on the Iberian Peninsula. The
Iberian Flora collection refers to the Alt Empordà population
as corresponding to E. angulata Jacq. (Benedí & al., 1997),
while other studies conrm the presence of E. duvalii in
the Iberian Peninsula (Simon & Vicens 1999). At the
same time, the Flora Manual dels Països Catalans, ed. 3
describes a doubtful presence of this taxon in the territori
ruscínic ―Ruscinicum― (Bolòs & al. 2005).
With only one population on the Iberian Peninsula, this
unclear situation regarding the current status of E. duvalii
has generated a serious problem in terms of knowledge
about and conservation of this Mediterranean plant.
Because of its rarity, E. duvalii was declared as strictly
protected in Catalonia under the Pla d’Espais d’Interès
Natural (Generalitat de Catalunya 1993), which was then
later modied through the creation of the Catàleg de la
Flora Amenaçada a Catalunya (Generalitat de Catalunya
Keywords. Alt Empordà, Alta Garrotxa, conservation, singular ora,
protected species, Serra de Bac Grillera.
Palabras clave. Alto Ampurdán, Alta Garrotxa, conservación, especies
protegidas, ora singular, sierra de Bac Grillera.

J. Bou & J. Bou i Tomàs
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Anales del Jardín Botánico de Madrid 75 (2): e073. https://doi.org/10.3989/ajbm.2495
2008), which states this taxon as being a strictly protected
species of ora in the wilderness area of the Alta Garrotxa.
Therefore, in this study we wanted to check for the
presence of this species in the Alt Empordà through eld
work and by analysing the herbarium material while, at the
same time, contributing to the knowledge about this plant
by adding new chorological data about the one and only
population on the Iberian Peninsula. We also endeavour
to provide clarity and useful information to ensure the
preservation of this endemism of occidental Mediterranean
ora.
MATERIAL AND METHODS
The studied population of E. duvalii is found in the
eastern part of the Pre-Pyrenees mountain range known as
the Serra de Bac Grillera. It is inside the protected area of
the Alta Garrotxa which is included in the Pla d’Espais
d’Interès Natural and also the Xarxa Natura 2000 (g. 1).
Material was collected to carry out a morphological study,
and the specimens were later deposited in the Herbari de
la Universitat de Girona ―HGI―. An identication key
was constructed from the data collected, together with the
bibliographic information from Simon & Vicens (1999)
and Tison & al. (2014). All the studied specimens of
Euphorbia are listed in the appendix.
The site studied is an open wilderness space made up
of shrub lands and meadows (g. 2c) and surrounded by a
Scots pine forest. The ground is stony with disaggregated
red soils that have signs of a marked erosive processes.
As with the French populations, the substrate is calcareous
(Tison & al. 2014) and more specically in the Iberian case
there are calcareous rocks from Cretaceous and Garumnian
facies. The population is located 800 m a.s.l. on a north-east
facing site which produces the specic environmental
conditions of sub-Mediterranean limestone mountains.
RESULTS AND DISCUSSION
Morphology
The specimens of E. duvalii collected in the Serra de
Bac Grillera ―HGI 23815 and HGI 23816― correspond to
a perennial herbaceous plant and are usually glabrous and
Fig. 1. Populations of E. duvalii Lecoq & Lamotte in the western Mediterranean, and in detail in the locality of the Serra
de Bac Grillera; the known localities for eld work and bibliographic citations are represented. [Prepared by the authors;
sources: Generalitat de Catalunya (2017); Institut Cartogràc i Geològic de Catalunya (2017); Tela Botanica (2017)].

Euphorbia duvalii on the Iberian Peninsula 3
Anales del Jardín Botánico de Madrid 75 (2): e073. https://doi.org/10.3989/ajbm.2495
Fig. 2. Euhorbia duvalii Lecoq & Lamotte: a, complete plant with woody rhizomes; b, habitat where the Iberian population
grows in the Serra de Bac Grillera; c, capsule with sub-pyramidal and sub-conical warts [a, c, HGI 23815].

J. Bou & J. Bou i Tomàs
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Anales del Jardín Botánico de Madrid 75 (2): e073. https://doi.org/10.3989/ajbm.2495
multicauline. Stems are 10–20(25) cm long, ascending and
mostly simple and cylindrical. Woody rhizomes without
tuberculous structures are between a dark brown and
greyish colour and unarticulated. Leaves are of variable
morphology. There are numerous basal cataphylls 2–2.5 ×
1.5–2 mm which are scarious, obtuse and with a rounded
apex. Cauline leaves are [8]10–20[36] × [2.5]3–6[9.5] mm,
rm, sessile and alternate, lanceolate to elliptic in shape,
and denticulate in the upper half. Leaves from sterile stems
tend to be nely lanceolate and more acute towards the
apex. The pleiochasial bracts are [7]8–10[19] × [7]4–8[10]
mm, ovate to rhombic in shape which is often quite a lot
shorter than the radius. Dichasial bracts are [6]4–5[9] ×
[7]6–8[14]mm and oblate in shape with a mucronate apex.
They are pleiochasium, green, with a 3–5 oral radius,
albeit sometimes we were able to observe an axillar oral
radius. Nectar glands are a reniform shape and yellow in
colour. The sub-globular capsules are [3.3]3.6–4[4.8] mm
in diameter, glabrous and green but the mature capsules
are red-brown with warts visible to the naked eye. The
warts are [0.8]0.7–1.2[1.1] mm long, and although they are
thick, they are clearly longer than they are wide, and are
sub-pyramidal to sub-conical. The style is long, trifurcated
in the middle of the length and persistent to maturity. Seeds
are sub-globular with a truncated base and a subacute 2.5 ×
2 mm apex, which is smooth and dark brown. They are
reniform caruncle with an apparent frontal notch.
All these characteristics lead us to conclude that there
is a population of E. duvalii in the Serra de Bac Grillera as
the morphology of the specimens collected corresponds to
the descriptions of Simon & Vicens (1999) and Tison & al.
(2014). The same is observed for the samples collected in
1983 ―HGI 23847―, which also correspond to E. duvalii.
Furthermore, we have compared the material we collected
with the French specimens of E. duvalii from Mont Alaric
―HGI 23817― and with herbarium material ―BC
649310 and BC 649337―, and the same characteristics
are clearly identiable.
In addition, samples of other species ―E. dulcis and
E. angulata― that could be confused with E. duvalii have
been analysed. As has been observed, with the complete
sample of E. angulata ―BC 149063, BC 149079, HGI
23850, and HGI 23851―, the rhizome with nodules that
this taxon presents can be clearly seen, and so cannot be
confused with the woody rhizome of E. duvalii. However
the differences between the rhizomes of E. dulcis ―BC
651571 and BC 917673― and E. duvalii are not obvious at
rst sight, and so the capsules need to be analysed, because
E. dulcis has a lower density of warts than does E. duvalii
and they are also shorter.
To clarify these differences, the following identication
key has been developed:
1. Woody and unarticulated rhizomes. Sub-globular
capsules with 0.7–1.2 mm long sub-pyramidal to
sub-conical warts .......... E. duvalii Lecoq & Lamotte
– Fleshy and articulated rhizomes. Sub-globular capsules
with 0.4–0.7 mm long sub-conical warts .................. 2
2. Rhizomes with continuous segments …....… E. dulcis L.
– Rhizomes with discontinuous nodules ..........................
.......................................................... E. angulata Jacq.
State of conservation
The population of E. duvalii in the Serra de Bac
Grillera is unique to the Iberian Peninsula and, due to
its restricted distribution in France, its conservation is of
great importance. However, the possible presence in other
localities in the northeast of the Iberian Peninsula cannot
be discarded. To preserve this unique element of western
Mediterranean ora, knowledge concerning the biology
and ecology of this species needs to be extended and an
efcient management plan needs to be developed.
ACKNOWLEDGEMENTS
The authors would like to thank R.M. Manobens for her assistance in
collecting the plants and Dr. L. Vilar from the LAGP-Flora and vegetation
(UdG) for his timely and valuable advice.
REFERENCES
Benedí C., Molero J., Simon J. & Vicens J. 1997. Euphorbia L. In
Castroviejo S. & al. (eds.), Flora iberica 8: 210–285. CSIC, Madrid.
Bolòs O., Vigo J., Masalles R.M. & Ninot J. M. 2005. Flora Manual dels
Països Catalans, ed. 3. Pòrtic, Barcelona.
Bou i Tomàs J. 1985. Noves dades orístiques per a la ora de l’Alt
Empordà (NE de Catalunya). II. Collectanea Botanica 16 (1): 165–173.
Generalitat de Catalunya 1993. Decret 328/1992, de 14 de desembre,
pel qual s’aprova el Pla d’espais d’interès natural. Diari Ocial de la
Generalitat de Catalunya 1714: 1–17.
Generalitat de Catalunya 2009. Decret 172/2008, de 26 d’agost, de
creació del Catàleg de ora amenaçada de Catalunya. Diari Ocial de la
Generalitat de Catalunya 5204: 65881–65896.
Generalitat de Catalunya 2017. gencat.cat. Website: http://www.gencat.
cat/ [accessed 15–X–2017].
Institut Cartogràc i Geològic de Catalunya 2017. ICGC VISSIR.
Website: http://www.icc.cat [accessed 15–X–2017].
Molero J., Pujadas J. & Romo A.M. 1988. Noves dades corològiques
i taxonòmiques sobre la Flora dels Prepirineus centrals catalans.
Monográco Instituto Pirenaico de Ecología 4: 265–281.
Pujadas J. 1981. Algunes plantes del Boumort. Butlletí de la Institució
Catalana d’Història Natural 46 (4): 101–102.
Romo A.M. 1989. Flora i Vegetació del Montsec (Pre-Pirineus catalans).
IEC, Barcelona.
Simon J. & Vicens J. 1999. Estudis biosistemàtics en Euphorbia L. a la
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Tison J.-M., Jauzein P. & Michaud H. 2014. Flore de la France
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APPENDIX
Euphorbia duvalii Lecoq & Lamotte
FRANCE. Aude: Comingne, Mont Alaric (Corbières), 23–VII–2017,
J. Bou, R.M. Manobens and J. Bou Manobens s.n. leg. (HGI 23817);
Gard, Fontaret, près de Blandas, 21–VI–1880, L. Anthonard s.n. leg. (BC
649310). Unknown department: Pert, V–1889, L. Giraudias s.n. leg. (BC
649337).
SPAIN. Girona: Alt Empordà, Maçanet de Cabrenys, a la Serra de Bac
Grillera, a la Collada dels Gesos, 31TDG7689, 750 m a.s.l., 24–VI–2017,
J. Bou Manobens, J. Bou i Tomàs and R.M. Manobens s.n. leg. (HGI
23815, HGI 23816); Alt Empordà, Maçanet de Cabrenys, calcàries del
Castell de Bac Grillera, DG79, 750 m a.s.l., 05–VI–1983, J. Bou i Tomàs
s.n. leg. (HGI 23847).
Euphorbia dulcis L.
SPAIN. Lleida: Alt Urgell, la Guàrdia d’Ares, Barranc Fondo, 10–VII–
1980, J. Molero and J. Pujadas s.n. leg. (BC 651571). Asturias: Oviedo,
Monte Naranco, 30TTP70260757, 288 m a.s.l., 16–IV–2011, M.C. Fdez.-
Carvajal s.n. leg. (BC 917673).
Euphorbia angulata Jacq.
SPAIN. Girona: Ripollès, Sant Amanç, 1700 m a.s.l., 26–VI–1962, J.
Vigo s.n. leg. (BC 149063); Ripollès, Sant Amanç, 1700 m a.s.l., 17–VIII–
1962, J. Vigo s.n. leg. (BC 149079); Alt Empordà, Maçanet de Cabrenys,
les Salines, DG79, 1000 m a.s.l., 13–VI–1983, J. Bou i Tomàs s.n. leg.
(HGI 23850); Alt Empordà, Maçanet de Cabrenys, vers Tapis, DG79,
500 m a.s.l., 3–VII–1983, J. Bou i Tomàs s.n. leg. (HGI 23851).