Polycarpon dunense (Caryophyllaceae), a new psammophilous species from Minorca (Balearic Islands) [Polycarpon dunense (Caryophyllaceae), nueva especia psamófila de Menorca (Islas Baleares)]

Eds., Gonzalo Mateo Sanz & José Luis Benito Alonso

Description

ABSTRACT: A new annual species, Polycarpon dunense P. Fraga & Rosselló (Caryophyllaceae), is described from the coastal sand dunes of northern Minorca (Balearic Islands). Polycarpon dunense is diploid (2n=16) and can be distinguished from the related taxa by a combination of characters including a small size and a prostrate habit, a glaucous leaf colour, leaf succulence, ovate leaf shape, narrower leaf size, smaller bract length, obtuse sepal apex, and smooth seed ornamentation.
RESUMEN: Se describe una nueva especie anual, Polycarpon dunense P. Fraga & Rosselló (Caryophyllaceae), de las dunas costeras del norte de Menorca (Islas Baleares). Polycarpon dunense es diploide (2n=16) y puede ser discriminada de las otras especies relacionadas por una combinación de caracteres entre los que destacan un tamaño pequeño y hábito postrado, la coloración glauca de sus hojas así como su suculencia foliar, la forma oval de las hojas y su menor tamaño, la longitud menor de sus bràcteas, los ápices obtusos de sus sépalos y la ornamentación lisa de la testa seminal.

Sujets

• Vascular plant
• Caryophyllaceae
• Polycarpon
• Endemism
• Minorca
• Balearic Islands
• Spain
• Mediterranean Sea
• Endemismo
• Menorca
• Islas Baleares
• España
• Mediterráneo occidental

Informations

• Publié par: erevistas
• Publié le: 01 janvier 2011
• Nombre de lectures: 44

Extrait

Flora Montiberica 47: 29-35 (I-2011). ISSN 1138-5952

POLYCARPON DUNENSE (CARYOPHYLLACEAE), A NEW
PSAMMOPHILOUS SPECIES FROM MINORCA (BALEARIC
ISLANDS)

Pere FRAGA* & Josep A. ROSSELLÓ**

* Verge del Toro, 14, E-07750 Ferreries, Menorca (Islas Baleares). E-mail:
[e-mail]
** Jardí Botànic, Universitat de València. C/Quart 80, E-46008 València
& Marimurtra Bot. Garden, Carl Faust Fdn., PO Box 112, E-17300 Blanes (Gerona). E-
mail: [e-mail]



SUMMARY: A new annual species, Polycarpon dunense P. Fraga & Rosselló (Caryo-
phyllaceae), is described from the coastal sand dunes of northern Minorca (Balearic Islands).
Polycarpon dunense is diploid (2n=16) and can be distinguished from the related taxa by a combi-
nation of characters including a small size and a prostrate habit, a glaucous leaf colour, leaf suc-
culence, ovate leaf shape, narrower leaf size, smaller bract length, obtuse sepal apex, and smooth
seed ornamentation. Key words: Endemism, Minorca, Balearic Islands, Western Mediterranean.


RESUMEN: Se describe una nueva especie anual, Polycarpon dunense P. Fraga & Ros-
selló (Caryophyllaceae), de las dunas costeras del norte de Menorca (Islas Baleares). Polycarpon
dunense es diploide (2n=16) y puede ser discriminada de las otras especies relacionadas por una
combinación de caracteres entre los que destacan un tamaño pequeño y hábito postrado, la colora-
ción glauca de sus hojas así como su suculencia foliar, la forma oval de las hojas y su menor ta-
maño, la longitud menor de sus bràcteas, los ápices obtusos de sus sépalos y la ornamentación lisa
de la testa seminal. Palabras clave: Endemismo, Menorca, Islas Baleares, Mediterráneo occi-
dental.

quences has shown that Polycarpon as cu-INTRODUCTION
rrently recognised is polyphyletic, with
Polycarpon (Caryophyllaceae) as tra- South American species more closely re-
ditionally circumscribed is a genus of lated to Haya obovata (Socotra) and Poly-
about 16 species distributed through the carpaea spicata (paleotropical) than to
warm and temperate regions of both he- the remaining species of Polycarpon, and
mispheres (PEDERSEN, 1987). The ge- the widespread tropical species P. pros-
nus has been traditionally placed in the tratum was nested with Macaronesian spe-
tribe Polycarpeae of the subfamily Paro- cies of Polycarpaea (KOOL & al., 2007).
nychioideae (BITTRICH, 1993), although The taxonomic classification of the
recent phylogenetic work within the fa- genus in the Mediterranean area has been
mily suggests that tribe Polycarpeae is at built on the basis of the life form. In this
least paraphyletic (SMISSEN & al., 2002). way two main groups are distinguished:
Recent phylogenetic work on Polycarpon annual plants are grouped in the P. tetra-
using nuclear and chloroplast DNA se- phyllum (L.) L. complex, while the peren-
29 Polycarpon dunense: a new psammophilous species from Minorca (Balearic Islands)
nial ones included a closely related group Derivatio nominis: from its psammo-
of taxa in the P. polycarpoides (Biv.) Fio- philous habitat.
ri complex (FIORI, 1923-1925; QUÉZEL

& SANTA, 1962; PIGNATTI, 1983; DESCRIPTION
BOLÒS & VIGO, 1990; AMICH & PE-
DROL, 1990). Moreover, concerns about Small annual 0,5-1 cm high; main
the number and taxonomic delimitation of stem simple or branched radially just
species within each group have been poin- above the epicotyl, thus each plant has
ted out by several authors (e.g., CHATER typically a rounded outline; branches
& AKEROYD, 1993; JEANMONOD, short, 0,5-3 cm long, prostrate, stems red;
2004). Even some authors (KOOL & al., root system formed by a main slender
2007) included all Mediterranean species, taproot, 5-10 cm long, with numerous
either perennial or annual, within a single capillary secondary roots in the lower
polymorphic taxon (the P. tetraphyllum half; leaves opposite, fleshy, glabrous,
group). silvery glaucous, the lower ones tinged
During field work devoted to study the red at the anthesis, basal leaves orbicular
flora of the dune systems of Minorca se- spatulate, caulinar leaves elliptic to ovate,
veral annual populations of Polycarpon blade 1,5-5,3 x 1-3,3 mm, the lower and
were found. The plants were morphologi- middle ones petiolate, petiole 1-3 mm,
cally quite different from any taxa pre- upper ones sessile or subsessile, apex
viously described within the P. tetraphy- obtuse or subacute, margins entire; stip-
llum complex. In fact, some morphologi- ules up to 1,5 mm long, silvery white,
cal characters shows more similarities with papery, broadly triangulate, obtuse or
the perennial plants of the P. polycarpoi- subacute, with the margins denticulate
des group, like the presence of a well dif- fimbriate; inflorescence a much branched,
ferentiated taproot, fleshy leaves or obtuse congested cyme; inflorescence branches
sepals. The examination of herbaria speci- very short, usually less than 1 mm; pedi-
mens from the whole Mediterranean have cels up to 1,25 mm; bracts conspicuous,
revealed that these plants from dune envi- silvery white, resembling the stipules, but
ronments belong to a new species so far narrower and long acuminate; sepals with
restricted to Minorca. Accordingly, they a rounded back, not keeled, margins hya-
are here described as P. dunense and the line, wide, apex cucullate, rounded, the
evidences for this are given below. outer narrowly ovate, 1,8-2,4 x 0,6-0,9
mm, the inner wider, 1,8-2,6 x 0,8-1,2
Polycarpon dunense P. Fraga & Rosse- mmm; petals shorter than the sepals,
lló, sp. nova (Fig. 1) membranous, hyaline, oblong, up to 1 mm
Diagnosis. A Polycarpon polycarpoi- long and 0,5-0,7 mm wide, apex obtuse
des similis, sed annua, parvula, foliis ova- and slightly dentate; stamens 3, about 1
libus, minores et angustiores (1.5-5 x 1-3 mm long; anthers pale yellow, subor-
mm), bracteis longioribus (1-1.5 mm), bicular, 0,2-0,4 mm diameter; ovary sub-
stamina numeri (3) et chromosomatum globose, about 0,8 mm diameter; style
numerum (2n=16) differt. very short, 0,1-0,2 mm long, bifid above.
Type: Minorca. In arenosis loco dicto Capsule pale yellow, 1,7-2,1 mm long,
Arenal de sa Cavalleria, ad 10 m, 31TEE 1,4-1,7 mm wide, walls of valves in-
919348, ubi P. Fraga 31-III-1996 legit curved after dehiscence; seeds 0,4-0,6
(Holotypus:VAL 202229; Isotype: herba- mm long, 0,3-0,5 mm wide; testa whitish
rium P. Fraga). brown, smooth. 2n=16.


30
Flora Montiberica 47: 29-35 (I-2011). ISSN 1138-5952 P. FRAGA & J.A. ROSSELLÓ
COMPARATIVE MORPHOLOGY a similar growth habit, like Arenaria lep-
toclados (Rchb.) Guss., Cerastium semi-
The new species found in three dune decandrum L., Lobularia maritima (L.)
systems of the north coast of Minorca Desv., Malcolmia ramosissima (Desf.)
show morphological features and ecologi- Thell., Rumex bucephalophorus L., Sene-
cal preferences that allow an easy dis- cio vulgaris L., Silene sclerocarpa Dufour
crimination from the known taxa of the Silene sedoides Poir., Valantia muralis L.
genus in the Mediterranean region. The Also, some Balearic endemics can rarely
new species could be easily differentiated be found in this habitat (Senecio rodri-
by a combination of characters including guezii Willk., P. colomense Porta).
a small size and a prostrate habit, a glau- The particular environment shown by
cous leaf colour, leaf succulence, ovate P. dunense has substantial differences
leaf shape, narrower leaf size, smaller with the other taxa of the genus present in
bract length, obtuse sepal apex, and Minorca. On the one hand, members of
smooth seed ornamentation. Morphologi- the P. tetraphyllum group (including var.
cal key features used to discriminate P. diphyllum (Cav.) DC. and subsp. alsini-
dunense from the taxa included within the folium) that are commonly found in sand
P. tetraphyllum complex are reported in dunes, usually grow in established soils
Table 1. Furthermore, P. dunense is dip- and with a significant presence of organic
loid, in contrast with the higher ploidy litter. On the other, P. colomense mainly
levels usually reported within P. tetra- grows in coastal rocky slopes throughout
phyllum. all the Eastern Balearic Islands, although
In addition, the annual life cycle, the it rarely grows in sympatry with P. dun-
presence of conspicuous stipules, and the ense.
number of stamens (3) are the main char- Despite its small size and annual life
acters to differentiate it from the perennial cycle, P. dunense can not be considered
taxa included within the P. polycarpoides as an ephemeral therophyte. It start to
group. germinates with the first abundant rains in
October or November and its flowering
period occurs from April to June. So it HABITAT AND DISTRIBUTION
has a life span similar to any winter
Currently, Polycarpon dunense is only growing Mediterranean annual.
known from three localities in the north The particular habitat of P. dunense
coast of Minorca (Fig. 2). It grows exclu- could be linked to some morphological
sively in well preserved coastal sand features exhibited by the new species.
dunes,