AJBM Anales del Jardín Botánico de Madrid 0211-1322 1988-3196 Consejo Superior de Investigaciones Cientificas AJBM201806-2501 10.3989/ajbm.2501 Articles Euphorbia paniculata subsp. calcicola U.Schwarzer & Vicens subsp. nov. (Euphorbiaceae), a new taxon of the southwestern Portugal Euphorbia paniculata subsp. calcicola U.Schwarzer & Vicens subsp. nov. (Euphorbiaceae), un nuevo taxon del sudoeste de Portugal Euphorbia paniculata subsp. calcicola U.Schwarzer & Vicens subsp. nov. (Euphorbiaceae), a new taxon of the southwestern Portugal Schwarzer Udo 1 * Fandos Josep Vicens 2 Apartado 1020, 8671–909 Aljezur, Portugal Laboratori de Botànica, Facultat de Farmàcia i Ciències de l’Alimentació & Centre de Documentació de Biodiversitat Vegetal, Universitat de Barcelona, Av. Joan XXIII 27–31, 08028 Barcelona, Spain Author for correspondence: pb@biopiscinas.pt, https://orcid.org/0000-0003-2910-0606 vicens@ub.edu, https://orcid.org/0000-0002-7061-7060

Associate Editor: C. Aedo.

 13 11 2018 2018 75 2 10.3989/ajbm.2501 14 02 2018 24 05 2018 © 2018 CSIC 2018 This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial (by-nc) Spain 4.0 License. Abstract

A new subspecies of E. paniculata Desf., E. paniculata subsp. calcicola U.Schwarzer & Vicens subsp. nov., is described. It grows in the proximity of the town of Sagres —southwestern Portugal— on calcareous substrate.

 Resumen

Se describe una nueva subspecie de E. paniculata Desf., E. paniculata subsp. calcicola U.Schwarzer & Vicens subsp. nov. Crece en la proximidad de la ciudad de Sagres —suroeste de Portugal— en sustrato calcáreo.

 Keywords Euphorbiaceae Iberian Peninsula taxonomy Palabras clave Euphorbiaceae Península Ibérica taxonomía INTRODUCTION

The genus Euphorbia L., in strict sense, is represented in the Iberian Peninsula by 54 species (Benedí & al. 1997). Some species are quite variable morphologically and subespecies are recognized. This is the case of E. paniculata Desf., a species with a wide distribution range in the Iberian Peninsula and North Africa. This species has habitat preferences restricted to marshes or areas close to streams, which result in populations appearing in isolated patches. In the Iberian Peninsula, E. paniculata was previously known from its southwestern quadrant (Benedí & al. 1997) until further explorations discovered some populations in the southeastern provinces of Murcia and Almería (Sánchez Gómez & al. 2006).

During recent fieldwork in the Sagres Peninsula of Portugal, two populations of Euphorbia with unclear identity were discovered. The general aspect resembled E. paniculata subsp. monchiquensis (Franco & P.Silva) Vicens, Molero & C.Blanché, but the leaves were clearly different, more similar to those of E. clementei Boiss.

 MATERIAL AND METHODS

Some specimens were collected in order to be preserved in BCN, LISE and the personal herbarium of one the authors —U. Schwarzer—. Their morphology was compared to individuals of E. paniculata subsp. monchiquensis from populations in the southern Portugal and to herbarium specimens kept in BCN.

In addition, one specimen —SALA 41999— from this area —identified by Vicens & al. (1996) and Simon & Vicens (1999) as E. clementei— was also revised.

 RESULTS Taxonomic treatment

After examining the specimens and attending the existence of taxonomic characters to discriminate the studied individuals from other subspecies of E. paniculata we propose this new taxon:

Euphorbia paniculata subsp. calcicola U.Schwarzer & Vicens subsp. nov. Types: Portugal, Sagres, Barranco do Martinhal, lat. 37.019868, long. –8.935009, 2–IV–2017, U. Schwarzer US03_2017_01 (holo-: BCN 143355). Portugal, Sagres, Barranco do Rebolinho, lat. 37.026507, long. –8.922868, 5–V–2017, U. Schwarzer US05_2017_02 (para-: ex herb. U. Schwarzer). Portugal, Vila do Bispo, Sagres, Barranco do Martinhal, 18–III–2018, U. Schwarzer US03_2018_01 (para-: LISE 96315). Portugal, Sagres, 4–V–1980, F. Amich, E. Rico and J. Sánchez s.n. (para-: SALA 41999). Figs. 1, 2.

Young leaves of E. paniculata subsp. calcicola U.Schwarzer & Vicens subsp. nov. from Sagres —Algarve, Portugal—. [Photograph by U. Schwarzer, 5–XI–2017.]

Habit of E. paniculata subsp. calcicola U.Schwarzer & Vicens subsp. nov. from Sagres —Algarve, Portugal—. [Photograph by U. Schwarzer, 2–IV–2017.]

LSID: urn:lsid:ipni.org:names:77185791-1

Euphorbia paniculata subsp. calcicola subsp. nov. is closely related to E. paniculata subsp. monchiquensis (fig. 3), from which it differs in its higher stature, growing as a slender bush with 3–4 woody stems up to 200 cm, leaves shorter and more elliptic to ovate —lanceolate in E. paniculata subsp. monchiquensis—. Especially when young, the leaves are densely covered with short hairs (fig. 1), the older leaves keep the hairs along the margin and along the abaxial midrib. The bracts are ovate to rhomboid-orbicular and not ovate to lanceolate. The capsules differ in the pattern of surface papillae. Euphorbia paniculata subsp. paniculata and E. paniculata subsp. welwitschii (Boiss. & Reut.) Vicens, Molero & C.Blanché are quite different from E. paniculata subsp. calcicola subsp. nov.: they are shorter plants, up to 70 (100) cm high, and their leaves have a truncate base. The differences are summarized in table 1.

Comparison of the four subspecies of E. paniculata Desf.

E. paniculata Desf. subsp. paniculata E. paniculata subsp. welwitschii (Boiss. & Reut.) Vicens & al. E. paniculata subsp. monchiquensis (Franco & P.Silva) Vicens & al. E. paniculata subsp. calcicola U.Schwarzer & Vicens subsp. nov.
Lifeform Hemicriptophyte or chamephyte slightly lignified at base Hemicriptophyte Nanophanerophyte or chamephyte lignified at base Nanophanerophyte with woody stems
Length up to 70 (100) cm up to 70 (100) cm up to 150 cm up to 200 cm
Leaves 25–60 (70) × 15–25 mm, oblong-lanceolate, margins normally serrulate and truncate base, glabrous or nearly glabrous 30–40 × 15–25 mm, elliptic, margins normally serrulate and truncate, glabrous (20) 40–100 × 10–20 mm, lanceolate, margins normally entire and attenuate base, glabrous or sparsely hairy (20) 25–35 × (5) 10–15 mm, elliptic to ovate, especially young leaves densely hairy, nearly tomentose, older leaves with hairs on leaf margin and midrib
Pleiochasial bracts 15–35 × 15–30 mm, elliptic 15–30 × 15–25 mm, ovate 20–75 × 15–30 mm, ovate to lanceolate 15–20 × 15–20 mm, ovate to rhomboid-orbicular
Capsule 4–6 mm, subspherical, covered with hemispheric papillae 4 mm, subspherical, covered with hemispheric papillae 4 mm, subspherical, densely covered with hemispheric papillae 3–4 mm, subspherical, sparsely covered with small papillae
Ecology Diverse habitats linked to water, including watercourses and marshes, on silicic substrate Humid places with Vinca difformis Pourr. and Rubus cf. ulmifolius Schott among shrublands on alkaline substrate, Viburno tini-Quercetum cocciferae Rivas Martínez & al 1990 Relict groves of Quercus canariensis Willd., on silicic substrate, characteristic to Euphorbio monchiquensis-Quercetum canariensis Malato Béliz in Rivas Martínez & al. 1990, but also in other habitats (Fox & Deil 2004). Banks in dry seasonal water courses, on alkaline substrate —lime—, in permanent shrub communities of Asparago albi-Rhamnion oleoidis Rivas-Goday ex Rivas Martítez 1975
Altitude 100–900 m a.s.l. 50–200 m a.s.l. 100–600 m a.s.l. 10–30 m a.s.l.
Chorology Scattered through South of Iberian Peninsula and coast of the Maghreb Endemism of Serra de Sintra and surroundings of Lisbon Endemism of Serra de Monchique —Algarve, Lower Alentejo—, southern Portugal Endemism of Sagres Peninsula —Algarve—, southwestern Portugal

Young leaves of E. paniculata subsp. monchiquensis (Franco & P.Silva) Vicens & al. from Aljezur —Algarve, Portugal—. [Photograph by U. Schwarzer, 5–IX–2017.]

Etimology.—From Latin calcicolus, -a, -um: that thrives in calcareous soil.

Distribution and habitat.—The new subspecies was found in two dry seasonal water courses in the Sagres Peninsula —Costa Vicentina, Algarve, southwestern Portugal— (figs. 2, 4). The habitat is densely covered with a Mediterranean permanent shrub community of the Asparago albi-Rhamnion oleoidis Rivas-Goday ex Rivas Martínez 1975. Due to constant winds on this southwestern edge of the European continent, this community has to be considered as climax stadium of the vegetation. The new taxon of Euphorbia grows sheltered by the bushy vegetation.

Distribution maps: a, E. paniculata subsp. monchiquensis (Franco & P.Silva) Vicens & al. in Portugal (Carapeto & al. 2017); b, E. paniculata subsp. monchiquensis —yellow contour, approximate— with those localities checked for this work —red dots—, as well as those of E. paniculata subsp. calcicola U.Schwarzer & Vicens subsp. nov. —red dots within blue contour.

 Identification key for the subspecies of Euphorbia paniculata

The new subspecies can be inserted in existing taxonomic keys (Benedí & al. 1997) as follows:

1. Plant up to 70 (100) cm, leaves truncate at the base 2
– Plant up to 150 to 200 cm, leaves attenuate 3
2. Leaves oblong-lanceolate; seeds 3–4 mm long E. paniculata Desf. subsp. paniculata
– Leaves elliptic, seeds 2.3 to 2.8 mm long E. paniculata subsp. welwitschii (Boiss. & Reut.) Vicens & al.
3. Plant up to 150 cm; leaves up to 100 mm long, lanceolate; pleiochasial bracts up to 75 mm long, from ovate to lanceolate E. paniculata subsp. monchiquensis (Franco & P.Silva) Vicens & al.
– Plant up to 200 cm; leaves up to 35 mm long, elliptic to ovate; pleiochasial bracts up to 20 mm long, ovate to rhomboid-orbicular E. paniculata subsp. calcicola U.Schwarzer & Vicens subsp. nov.
DISCUSSION

As a southwestern Iberian endemism, E. paniculata subsp. calcicola subsp. nov. occurs only in the thermomediterranean, dry, and rocky limestone coastland of Sagres Peninsula, where it copes with long drought periods.

This taxon is restricted to places very close to seasonal water courses which have water only for a few hours during rainfall events. Within this microhabitat the plants occupy the first bank, about one meter above the bed of the water course. The habitat of E. paniculata subsp. calcicola subsp. nov. is close to the Atlantic Ocean, but plants occur only in sites at elevation higher than 10 m a.s.l. Due to the short length of the water courses one can find plants between 10 and 30 m a.s.l.

The geological ages of the localities are Early Miocene and Upper Jurassic. The plants grow in clayey soil as weathering product of the dominant limestone rock.

The origin of this subspecies could be explained (Vila-Viçosa & al. 2018) by the splitting of the distribution area of an ancestral form of E. paniculata, which potentially occupied most of the southern Iberian Peninsula —Algarve and Andalusia— at the time of maximum glaciation in Europe —about 20.000 years—. At this time the area was occupied by the ancestors of the Euphorbio-Quercetum canariensis Woodland.

The population of E. paniculata subsp. calcicola subsp. nov. is estimated in 50–100 individuals and thus has to be considered as a threatened species. Despite the fact that the plants are growing within a protected area —Parque Natural do Sudoeste Alentejano e Costa Vicentina— they are threatened by intensive grazing. During the drought period in late summer and autumn, sheeps and goats invade the permanent shrub communities of Quercus coccifera L. and other bushes where E. paniculata subsp. calcicola subsp. nov. occurs. The plants are not affected by direct grazing but by the activity of the livestock around the bushes seeking edible plants under the shelter of tall plants.

 ACKNOWLEDGEMENT

We are grateful to C. Benedí whose comments and corrections improved the original typescript. And we thank C. Schwarzer for help and advice during the field work.

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