Limonium nichoriense Apostolopoulos & Constantinidis

Apostolopoulos, Efstathios & Constantinidis, Theophanis, 2024, Limonium ophioides and L. nichoriense (Plumbaginaceae), two new diploid species from Peloponnisos, Greece, Phytotaxa 655 (2), pp. 159-172 : 164-169

Limonium nichoriense Apostolopoulos & Constantinidis sp. nov. ( Fig. 4 , 5 )

Type:― GREECE. Peloponnisos: Nomos Messinias, Eparchia Pilias. The coastal area of Petalidi village. Isolated rocks on the sandy shoreline. In sand cavities among limestone rocks. Alt. 1 m, 36°57′18′′N, 21°56′05′′E, 20 August 2023, E. Apostolopoulos & K. Ntokopoulou no 674 (holotype ATHU!, isotypes B!, M!).

Description: —Plant perennial, glabrous, forming a sub-shrub 20–50 cm tall, with many erect, green stems and a robust taproot. Caudices robust, 4–10 cm long, branched, covered by rosette leaves at apices. Leaves fleshy, green, glabrous, rugose, usually withered at anthesis, 20–50 mm long and 2.5–5 mm broad, narrowly spathulate, revolute at margin, retuse to obcordate at apex, with one central nerve, lamina gradually tapering into petiole. Stems numerous, densely but very shortly papillate-hairy near the base, weak, very flexuous, fragile at the nodes, smooth to rugose, very branched, with the first branching point 1–5.5 cm above the leaf rosette. Stem internodes 1.5–2.5 cm long. Sterile branches 8–12 per stem, slightly curved, slightly articulate, usually unbranched, 1–4.5 cm long, forming branching angles of 30°–60°. Fertile branches 4–8 per stem, confined to the upper third of the stems, slightly articulate, usually unbranched, 1–5 cm long, slightly curved to straight, erect, forming branching angles of 30°–40°. Inflorescence obtrullate in outline. Spikes 15–55 mm long, straight to slightly curved. Spikelets weak to slightly thick, straight, 5–6 mm long, composed of 2–3 flowers, densely arranged at 6–9 per cm. Outer bract 1–1.5 mm long and 1–1.2 mm broad, glabrous, triangular-ovate; bract margin narrowly membranous; central part fleshy, acuminate. Middle bract membranous, glabrous, 1.5–2 mm long and 1–1.3 mm broad, elliptic, obtuse. Inner bract 3–3.8 mm long and 2.3–2.5 mm broad, glabrous, rugose, elliptic, rounded, with a broad membranous margin 0.5–0.8 mm wide; central part fleshy, forming a triangular tip 0.4–0.6 mm long, nearly reaching the upper margin. Calyx 4–4.5 mm long, exceeding the inner bract by 1.5–2 mm. Calyx tube densely hairy at the base, sparsely hairy at the middle, and glabrous at the upper part; calyx hairs variable in length. Calyx ribs ending shortly above the base of lobes; calyx lobes ca. 0.5–0.7 mm long, semi-elliptic to acute. Corolla pale violet. Seeds 1.4–1.7 mm long and 0.4–0.5 mm wide.

Etymology:— The specific epithet “ nichoriense ” is derived from the archaeological site of Nichoria, renowned for its Mycenaean civilization ( Shelmerdine 1981), situated approximately 9 km north of the species’ locus classicus.

Habitat and distribution: — Limonium nichoriense ( Fig. 5 ) is restricted to its type locality close to Petalidi village, located on the western coast of the Messenian Gulf, approximately 14 km southwest of Messini, 20 km southwest of Kalamata, and 25 km east of Pylos. Specifically, the new species grows in the coastal region south of the village’s small harbor, within a narrow expanse of limestone rocks at 1 m above sea level, amidst adjacent sandy areas. L. nichoriense prefers habitats near the sea, often nestled within sand pockets among limestone rock recesses along the rocky coastline, influenced by marine mists. Vegetation in this habitat is sparse, predominantly composed of Limonium , alongside a few more halophytes such as Crithmum maritimum Linnaeus (1753: 246) and Lotus cytisoides Linnaeus (1753: 776) . Beyond this halophytic zone, a mixture of maquis and phryganic vegetation prevails. Anthropogenic activities, such as tourism and residential development have significantly altered the coastal area encompassing the species’ distribution. Moreover, the prevalent sandy terrain along the coast hinders any new colonization of the species. Despite comprehensive surveys, no additional populations of the species were discovered in this region.

Phenology: —Flowering from June to October, fruiting from August to December.

Conservation status: — Limonium nichoriense occurs in a very small and restricted population, with the total number of mature individuals counted during fieldwork as 40, which is below the threshold for Critically Endangered under Criterion D of IUCN (2022). Moreover, it has an area of occupancy and an extent of occurrence of less than 10 km 2 and is found at just one location. A continuing decline in the extent and quality of habitat is inferred, as its habitat is subject to the expansion of invasive species, namely Carpobrotus edulis ( Linnaeus 1759: 1060) N.E. Brown (1926: 249) , Oxalis pes-caprae Linnaeus (1753: 434) , Opuntia ficus-indica ( Linnaeus 1753: 468) Miller (1768) and Mesembryanthemum cordifolium Linnaeus f. (1782: 260) , as well as anthropogenic interventions. Therefore, the species is assessed as Critically Endangered under the criteria B1ab(iii)+2ab(iii) and D.

Reproductive pattern:— The investigation of pollen and stigma morphologies revealed that the breeding system of Limonium nichoriense is similar to that of L. ophioides . The population is characterized by a dimorphic selfincompatibility system, with almost equal percentages of the two different pollen and stigma types. The pollen grains are mostly viable, tricolpate, and consistent in size. Therefore, the species reproduces sexually.

Cytology: — Limonium nichoriense is diploid with 2 n =2x=18 ( Fig. 6 ). Chromosome morphology seems to be related to that of L. ophioides , but metaphase plates were less helpful in observing details.

Taxonomic remarks:— Limonium nichoriense shares the taxonomic position within the “Mediterranean lineage” of L. subgenus Limonium , as defined by Koutroumpa et al. (2018), alongside L. ophioides . Furthermore, L. nichoriense falls within the “ L. cancellatum-dictyophorum ” group sensu Brullo & Erben (2016). L. nichoriense is morphologically most akin to L. pylium , found on the west coast of Peloponnisos, and L. coronense with a much narrower distribution in the same area. It distinguishes itself from both primarily by its smaller spikelets, inner bracts, and calyces ( Fig. 7 Α, 7C). In addition, L. nichoriense exhibits a retuse to obcordate leaf apex, whereas the other two species display an obtuse leaf apex ( Fig. 7D ). L. nichoriense also differs from L. coronense in its stem indumentum, exhibiting hairy stems near the base in contrast to the glabrous stems of L. coronense ( Fig. 7B ). A distinguishing feature unique to this new species within the “ L. cancellatum-dictyophorum ” group is the densely arranged spikelets, averaging 6–9 per centimeter ( Fig. 8 ), in contrast to the maximum of 5 per centimeter observed in other species of the group ( Artelari 1984, Brullo & Erben 2016). Further details on the morphological differences between L. nichoriense and its closest relatives are provided in Table 1 .

Key to Limonium species within the Limonium cancellatum-dictyophorum group occurring in Peloponnisos:

1. Sterile branches absent or few (1–3 per flowering stem), not articulate ............................................................................................2

- Sterile branches numerous (at least 7 per flowering stem), articulate................................................................................................3

2. Stems flexuous, branched near the base..................................................................................................................... L. messeniacum

- Stems unbranched........................................................................................................................................................... L. kardamylii

3. Stems pubescent near the base, calyx exceeding the inner bract by 1.5–2.2 mm ..............................................................................4

- Stems glabrous throughout, calyx exceeding the inner bract by 2.2–2.8 mm ....................................................................................5

4. Spikelets 6–9 per cm, branching angles 30°–60°, calyx 4–4.5 mm long...................................................................... L. nichoriense

- Spikelets 3–5 per cm, branching angles 70°–120°, calyx 4.5–5.2 mm long......................................................................... L. pylium

5. Inner bract 3–3.6 mm long, calyx 4–4.5 mm long, spikelets laterally slightly curved .................................................... L. ophioides

- Inner bract 3.6–4.2 mm long, calyx 4.9–5.6 mm long, spikelets straight ....................................................................... L. coronense

Additional specimen of Limonium ophioides examined (paratype): — GREECE. Peloponnisos: Nomos Lakonias, Eparchia Epidavrou Limiras. The coastal area between Paleokastro and Tsoumala, south of Agios Prokopios church and c. 6 km linear distance south of Neapolis Voion town. The rocky parts of the coastline along a hiking trail and close to a dirt road. Along with Lotus cytisoides , Cichorium spinosum , Frankenia hirsuta and Silene sedoides . Alt. 2–5 m, 36°27′52′′N, 23°04′11′′E, 21 October 2023, E. Apostolopoulos no 662 (ATHU!).

Additional specimen of Limonium nichoriense examined (paratype): — GREECE. Peloponnisos: Nomos Messinias, Eparchia Pilias. The coastal area of Petalidi village. Isolated rocks on the sandy shoreline. A severely degraded habitat with alien species like Carpobrotus edulis , Mesembryanthemum cordifolium and Opuntia ficus-indica . In sand cavities among limestone rocks. Alt. 1 m, 36°57′18′′N, 21°56′05′′E, 22 October 2023, E. Apostolopoulos no 667 (ATHU!).

Specimens of Limonium coronense examined: — GREECE. Peloponnisos: Nomos Messinias, Eparchia Pilias. The coastal area of Koroni town. The area around the castle of Koroni , situated at the southeastern part of the Messenian Bay . On the ruins and walls of the castle, next to a concrete coastal path.Alt. 1–5 m, 36°47′45′′N, 21°57′49′′E, 20August 2023, E. Apostolopoulos & K. Ntokopoulou no 671 ( ATHU!) ; Peloponnisos: Nomos Messinias, Eparchia Pilias. The coastal area of Koroni town. A place known as Paralia Zagka. Large boulders on the seashore, next to a large, sandy beach. Soil pockets in limestone rocks. Alt. 1–5 m, 36°47′35′′N, 21°57′40′′E, 20 August 2023, E. Apostolopoulos & K. Ntokopoulou no 672 ( ATHU!) ; Peloponnisos: Nomos Messinias, Eparchia Pilias. The coastal area ca. 2 km southeast of Finikounda town. A place known as Kantouni Beach. The rocky parts along a hiking trail near the coastline. Maquis vegetation. Limestone and conglomerates. Alt. 5 m, 36°47′47′′N, 21°49′23′′E, 17 March 2024, E. Apostolopoulos & E. Magdalinou no 804 ( ATHU!) .

Specimens of Limonium pylium examined: — GREECE. Peloponnisos: Nomos Messinias, Eparchia Trifilias. The coastal area of Lagouvardos settlement, 8 km SSW of Filiatra town. The open, rocky parts of a small sandy beach. Alt. 1–3 m, 37°05′51′′N, 21°34′35′′E, 29 October 2022, E. Apostolopoulos & E. Magdalinou no 165 ( ATHU!) ;

Peloponnisos: Nomos Ilias, Eparchia Ilias. The coastal area of Agios Andreas settlement, 2 km northwest of Katakolo town. The open, rocky parts of the beach, right next to concrete stairs. Alt. 1–2 m, 37°40′02′′N, 21°18′18′′E, 29 October 2022, E. Apostolopoulos & E. Magdalinou no 163 ( ATHU!) ; Peloponnisos: Nomos Messinias, Eparchia Trifilias. The coastal area of Agrilos settlement, 9 km southwest of Kiparisia town. The open, rocky, wet parts of the coastline. Alt. 1 m, 37°12′27′′N, 21°35′21′′E, 29 October 2022, E. Apostolopoulos & E. Magdalinou no 166 ( ATHU!) ; Peloponnisos: Nomos Messinias, Eparchia Trifilias. The coastal area of Pigadia settlement, 5 km southwest of Gargaliani town. The open, rocky parts of the coastline, near the road. Arenaceous limestone. Alt. 7–10 m, 37°02′04′′N, 21°36′16′′E, 29 October 2022, E. Apostolopoulos & E. Magdalinou no 168 ( ATHU!) ; Peloponnisos: Nomos Messinias, Eparchia Trifilias. The coastal area of Kalo Nero village, 6 km northeast of Kiparisia town. The open, rocky parts of a small sandy beach. Limestone. Alt. 1 m, 37°17′00′′N, 21°41′00′′E, 29 October 2022, E. Apostolopoulos & E. Magdalinou no 167 ( ATHU!) ; Peloponnisos: Nomos Messinias, Eparchia Pilias. The coastal area of Pylos town, east of the New Navarino fortress. A place known as Limanakia Beach. The rocky parts of the coastline. Limestone. Alt. 4 m, 36°54′30′′N, 21°41′24′′E, 17 March 2024, E. Apostolopoulos & E. Magdalinou no 803 ( ATHU!) ; Peloponnisos: Nomos Messinias, Eparchia Pilias. The coastal area of Methoni town, just south of the wastewater treatment facilities. The open, rocky parts of a small sandy beach. Alt. 5 m, 36°49′46′′N, 21°41′53′′E, 17 March 2024, E. Apostolopoulos & E. Magdalinou no 801 ( ATHU!) .

Distribution of all species: —Based on the examination of herbarium material attributed to Limonium ophioides , L. nichoriense , L. coronense , and L. pylium , alongside relevant literature sources ( Artelari 1984, Brullo & Erben 2016) a distribution map has been compiled ( Fig. 9 ). Limonium pylium is notably abundant along the Ionian coast of western Peloponnisos, with its northernmost occurrence near the coastal area of Loutra Killinis settlement, and its southernmost within the Methoni Castle. Limonium coronense is distributed across three populations, with the largest and easternmost one found in the coastal vicinity surrounding Koroni Castle, the westernmost near Finikounda village, and the last one approximately 15 km southwest of Koroni, at a place identified as Tsapi Beach. For each L. ophioides and L. nichoriense only one population is currently known.

Figures

FIGURE 4. Morphological features of Limonium nichoriense. A. Habit. B. Leaves. C. Spike. D. Spikelet. E. Calyx. F. Seeds. Illustration by Lydia A. Papadopoulou based on herbarium material from the type locality.

FIGURE 5. Limonium nichoriense A. Habitat. B. Habit. C. Leaves and stems. D. Detail of the inflorescence.

FIGURE 6. Mitotic metaphase plate of Limonium nichoriense with 2n=2x=18. Scale bar = 10 μm.

FIGURE 7. A. Inner bracts of Limonium coronense, L. pylium, L. nichoriense, and L. ophioides, arranged from left to right. B. Base of stems, with L. coronense on top and L. nichoriense on the bottom. C. Calyces of L. coronense, L. pylium, L. nichoriense, and L. ophioides, displayed from left to right. D. Leaf apex comparison, with L. coronense on the left and L. nichoriense on the right.

FIGURE 8. Spikes of Limonium coronense, L. nichoriense, and L. ophioides, arranged from left to right.

FIGURE 9. Geographical distribution of Limonium ophioides (green dot), L. nichoriense (blue dot), L. coronense (red dots) and L. pylium (purple dots).