Limonium cornarianum

Koutroumpa, Konstantina, 2024, Limonium artelariae (Plumbaginaceae), a new endemic species and further taxonomic and floristic notes on the genus in the island of Crete, Willdenowia 54 (1), pp. 65-79 : 67-68

The circumscription and distribution of Limonium cornarianum

In the area of Moni Kapsa ( Fig. 1 ), the narrow endemic Limonium cornarianum was originally described by Kypriotakis & Artelari (1998) from the calcareous rocks below the Kapsa monastery and the nearby gorge (named Moni Kapsa or Perivolakia gorge) that has an opening to the coast. Along the gorge, the species grows in crevices of steep cliffs ( Fig. 2A ) up to a distance of 1.5 km from the seashore ( Kypriotakis & Artelari 1998). Later collectors (see e.g. specimens in Brullo & Erben 2016 and photos in Kypriotakis & Artelari 2009) have assigned also Limonium plants from the coastal habitats of Moni Kapsa to L. cornarianum . During our fieldwork, we observed that the individuals growing along the coast ( Fig. 3 ) were morphologically different from the ones inside the gorge. The coastal populations fit the description of L. hierapetrae Rech. f. that has a wider distribution in SE Crete ( Rechinger 1943; Artelari 1989c). These observations were verified by (1) morphologically examining and comparing specimens from Moni Kapsa and the surrounding areas, including the type material of L. cornarianum and L. hierapetrae , and (2) analysing samples from the Moni Kapsa gorge and the coast (Kapsa beach) in a phylogenomic study that revealed their placement in different highly supported clades ( Koutroumpa 2020). The sample representing the coastal population is nested in the well-supported L. hierapetrae clade ( Koutroumpa 2020). The confusion of the L. hierapetrae samples from Kapsa beach with L. cornarianum explains the significant differences between the species description given by Brullo & Erben (2016: 101) and the protologue of L. cornarianum by Kypriotakis & Artelari (1998: 144). Brullo & Erben (2016) did not see the holotype of L. cornarianum and assigned further populations growing along the coast from Ierapetra to Moni Kapsa to L. cornarianum (see, e.g., B [ B 10 1189131]), which explains the much wider geographical distribution given by these authors for L. cornarianum that clearly overlaps with the known range of L. hierapetrae . In addition, the chromosome number 2 n = 43 given for L. cornarianum ( Brullo & Erben 2016) from material collected in Moni Kapsa matches the chromosome number of the pentaploid L. hierapetrae (2 n = 43, Artelari 1989c), whereas L. cornarianum is triploid according to our initial studies (see below). The material used for the chromosome counts by Brullo & Erben (2016) was most probably collected from the coast and belongs to L. hierapetrae (see B [ B 10 1132915]). Taken together, in the area of Moni Kapsa both L. cornarianum and L. hierapetrae co-occur ( Fig. 1 ) but occupy rather distinct habitats: L. cornarianum is restricted to crevices of calcareous rocks ( Fig. 2A ) and L. hierapetrae grows on the nearby pebbly beach ( Fig. 3 ) and in the maritime calcareous cliffs next to the beach. The two species can be easily distinguished by their different leaf shape ( Fig. 4 B, C ) and the smaller spikelets, spikelet bracts and calyces of L. cornarianum compared to L. hierapetrae ( Table 1 ).

Until now, Limonium cornarianum was known only from its locus classicus (Moni Kapsa) in SE Crete, where it is rare, comprising only few individuals ( Kypriotakis & Artelari 1998, 2009). The fieldwork in Crete revealed a new population of L. cornarianum in the NE part of the island ( Fig. 1 , 2B–D ). The population is geographically and ecologically distinct from the one in Moni Kapsa and located at the E edge of Pacheia Ammos cove in a dry salt-marsh habitat ( Fig. 1 , 2B ). Only few individuals (c. 10) were found, occupying a small area that seems to be seasonally flooded and is the mouth of a stream that runs through the gorge of Cha, which is located about three kilometres from the seashore ( Fig. 2B ). Because L. cornarianum is a chasmophyte of steep, usually inaccessible cliffs free of other vegetation in its locus classicus, it could be assumed that the species might also occur inside the Cha gorge and that the population in Pacheia Ammos was formed by seeds washed down the stream that runs through the gorge. Cha is a narrow inaccessible gorge with high vertical cliffs and chasmophytic vegetation that is botanically not well explored because its passage requires canyoning expertise. The individuals of the newly found population in Pacheia Ammos undoubtfully represent L. cornarianum ( Fig. 2C, D ). They are morphologically indistinguishable and form a well-supported monophyletic group in the phylogeny with individuals from the type locality ( Koutroumpa 2020). In addition, preliminary flow cytometric data of L. cornarianum from Pacheia Ammos indicate that the species is likely a triploid. Specifically, the 1 C genome size of L. cornarianum is 2.37 pg, which is comparable to the genome size of the triploid L. virgatum (1 C = 2.61 pg) and considerably smaller than the tetraploid L. aegaeum Erben & Brullo (1 C = 3.15 pg) and the pentaploid L. sitiacum Rech. f. (1 C = 3.52 pg). A triploid chromosome count is also found in L. aphroditae R. Artelari & Georgiou , an endemic in Kythira island that represents the closest morphological relative of L. cornarianum ( Artelari & Georgiou 1999) . Both species constitute a distinct morphological group compared to the other Aegean Limonium species, characterized by its small spikelet traits and sharing similarities with the C Mediterranean L. minutiflorum group that includes triploid and tetraploid taxa ( Artelari & Georgiou 1999). The close relationship of L. cornarianum and L. aphroditae was further supported by phylogenomic data ( Koutroumpa 2020).

Figures

Fig. 1. Distribution map of the closely related studied Limonium species in E Crete: L. artelariae, L. cornarianum and L. hierapetrae.

Fig. 2. Limonium cornarianum – A: individual growing on steep calcareous cliffs at the gorge of Moni Kapsa (locus classicus); B: habitat in Pacheia Ammos (new locality) with the Cha gorge in the background; C, D: inflorescence and habit of an individual in Pacheia Ammos. – All photographs taken by and © Konstantina Koutroumpa.

Fig. 3. Limonium hierapetrae growing on gravely soil at the coastal area of Moni Kapsa (Crete), habit and inflorescence. – All photographs taken by and © Konstantina Koutroumpa.

Fig. 4. Leaf shapes of the three closely related Limonium species in SE Crete – A: L. artelariae (K. Koutroumpa 299, UPA); B: L. cornarianum (K. Koutroumpa 751, Z [Z-000278454]); C: L. hierapetrae (K. Koutroumpa 269, Z [Z-000278465]). – Scale bar = 10 mm.