Carex distachya (Cyperaceae) with both subspecies in Europe

Introduction

The genus Carex L. (Cyperaceae) is species-rich, with more than 2000 species worldwide (POWO 2023). In Europe, Chater (1980) mentioned 180 species of Carex, while Koopman (2022) presents 235 species. The difference is partly due to the arbitrary use of the borders of Europe. Koopman (2022) included the three Caucasus countries, Armenia, Azerbaijan and Georgia, where several carices specific for the Caucasus or more Asian species which have their western border in the Caucasus can be found. On the other hand, since 1980 several new species have been described for Europe as well, e.g. C. randalpina B.Walln. (Wallnöfer 1993), C. pallidula Harmaja (Harmaja 2005), and C. castroviejoi Luceño & Jim.Mejías (Jiménez-Mejías & Luceño 2009). Molina et al. (2008a, 2008b) described another ten taxa within the section Phaestoglochin Dumort., including seven new species. Finally, some species have been discovered recently as new for Europe, e.g. C. kurdica Kük. ex Hand.-Mazz. (Jiménez-Mejías et al. 2013).

Chater (1980) put C. distachya Desf. into subgenus Indocarex Baillon, together with C. phyllostachys C.A.Mey. The former occurs in dry places in South Europe, in France, Spain, Portugal, Italy, Croatia, Bosnia and Herzegovina, Montenegro, North Macedonia, Albania, Greece, Bulgaria, and European Türkiye; the occurrence in Serbia and Romania needs confirmation (Koopman 2022; Fig. 1). It occurs also in North Africa (Algeria, Libya, Morocco, and Tunisia), as well as in Asian Türkiye. The last mentioned C. phyllostachys, a forest plant, was only known in Europe from W North Macedonia till 1980. More recently it has been found in several other (South) East European countries: Greece (Bergmeijer 1988, Authier 1997), Albania (Barina and Pifkó 2011), Italy (Wagensommer et al. 2014), and Croatia (Terlević et al. 2021). Carex phyllostachys is also known from Türkiye, Russia (Caucasus), Armenia, Azerbaijan, Georgia, and Iran (Koopman 2022).

Nilsson (1985) followed Chater (1980) by putting C. phyllostachys and C. distachya in subgenus Indocarex (Baillon) Kük., but added also C. illegitima Ces. to this subgenus. Carex phyllostachys and C. illegitima are both in section Phyllostachys (Torrey & A.Gray ex J.Carey) Bailey by Nilsson (1985), C. distachya is housed in section Schiedeanae Kük., although Nilsson (1985) is said to have treated this section within the subgenus Indocarex tentatively, and maybe it would be better to treat this section in subgenus Carex, close to section Hallerianae Asch. & Graebn. More recently, Roalson et al. (2021) placed C. phyllostachys in subgenus Psyllophora (Degl.) Peterm., in section Psyllophorae Degl.

Nilsson (1985) distinguished two varieties in C. distachya: C. distachya var. distachya and C. distachya var. phyllostachioidea Ö.Nilsson, the former being widespread in the Mediterranean (Fig. 1), the latter endemic to West Türkiye and the East Aegean Islands (Greece).

Fig. 1. Distribution of Carex distachya subsp. distachya. The map of the subspecies distribution (in green) follows Koopman (2022). It is also found on São Miguel, Azores. For the countries designated in orange, confirmation is needed. The red dots show the records indicated in the On-line Supplementary Material.

For many botanists the latter is a rather unknown taxon, as few botanists have ever visited the East Aegean Islands and/or do not have access to The Flora of Türkiye vol. 9, in which Nilsson described C. distachya var. phyllostachioidea (Nilsson 1985: 622). Moreover, as far as we know, apart from the description by Nilsson (1985) there has never been anything else written about C. distachya var. phyllostachioidea. Therefore, this taxon has stayed almost unnoticed since its description in 1985. Nilsson (1985) distinguished the two varieties as follows: leaves 0.5–1.5 mm broad; utricles almost veinless, beak not scabrid – C. distachya var. distachya; leaves 0.9–2.5 mm broad; utricles with 2 distinct veins, beak somewhat scabrid – C. distachya var. phyllostachioidea. The two distinct veins on the utricles are often difficult to see, but the differences in leaf width as well as the tiny teeth on the beak of C. distachya var. phyllostachioidea are clearly visible. Besides, in our opinion, the inflorescences of C. distachya var. phyllostachioidea are often significantly larger than those of C. distachya var. distachya.

As, according to Nilsson (1985), C. distachya var. phyllostachioidea is restricted to West Türkiye and the East Aegean Islands near the West coast of Türkiye, we have reckoned so far “automatically” all the found and collected material in South Europe to C. distachya var. distachya. In this article, we present our current knowledge of the distribution of C. distachya var. phyllostachioidea in Eurasia, which is probably not complete yet.

Material and methods

In this article we have analysed material of C. distachya s.l., available in B, BG, CL, CNHM, SOM, ZA, ZAGR, and the first author’s private herbarium, in total 95 collections (see On-line Supplementary material). In the Results below, collections with duplicates and exsiccates in several herbaria are counted only once. The herbarium acronyms follow Thiers (2024), the nomenclature Koopman (2022). All material has been checked against the characters of both C. distachya varieties given by Nilsson (1985), mentioned in the Introduction above.

Results and discussion

In May 2023 we found C. distachya on the Croatian island of Vis. The material had very narrow leaves and rather small inflorescences, so it was obviously C. distachya var. distachya, with smooth beaks. However, when we compared this material with all our previous collections, we came soon to the conclusion that several of these older collections are significantly different, with wider leaves, tiny teeth on the outside of the beak, and a larger inflorescence, hence belonging without any doubt to C. distachya var. phyllostachioidea, which is therefore proved to occur over a much larger area than so far known. Of the 95 herbarium collections studied in total, 83 belong to C. distachya var. distachya and 12 to C. distachya var. phyllostachioidea. The latter has been found and collected in Bulgaria, Croatia, Greece, and Montenegro, and was originally given for West Türkiye and the East Aegean Islands (Greece) by Nilsson (1985) (Fig. 2). Carex distachya var. phyllostachioidea is restricted to the East Mediterranean (Fig. 2).

Fig. 2. Distribution of Carex distachya subsp. phyllostachioidea. Four black dots in Türkiye represent localities reported by Nilsson (1985). Red dots represent new localities found in this study, and they are reported in the On-line Supplementary Material.

We therefore raise this variety here to subspecies rank:

Carex distachya subsp. phyllostachioidea (Ö.Nilsson) Jac.Koopman, Więcław, Bogdanović & T.Denchev stat. nov.

≡ Carex distachya var. phyllostachioidea Ö.Nillson in P.H.Davis (ed.), Fl. Turkey 9: 622 (1985)

Holotype: [Islands] Samos, valley W. of Leka, 200–400 m, Runemark & Snogerup 18861 (LD!)

However, the differences between the subspecies need some refinement. According to Nilsson (1985) the beak of C. distachya var. distachya is not scabrid, but smooth. A drawing of the utricles of both taxa is given by Nilsson (1985: p. 83). But in the material, we have studied we could see on several specimens a few tiny teeth on the beak of some utricles of further typical C. distachya var. distachya, i.e. with leaves (far) less than 1.5 mm wide. Often in one and the same spike or inflorescence there are utricles with a smooth beak and some have one or a few tiny teeth on the beak. On the other hand, material of typical C. distachya var. phyllostachioidea, i.e. with flat leaves mostly more than 2 mm wide, has several teeth on every utricle beak.

It is rather amazing that in the floristically best explored continent in the world, Europe, a new Carex taxon could be discovered, C. distachya subsp. phyllostachioidea. Of course, geographically, the East Aegean Islands, part of Greece, do belong to Europe. But Nilsson (1985) as well as Koopman (2022) count these islands as belonging botanically to West Asia. Anyway, our study has revealed that this taxon also occurs in several (other) South-eastern European countries, where it seems to have been overlooked so far. Further research is needed to find out the exact distribution of the two taxa, especially of C. distachya subsp. phyllostachioidea. The study of herbarium material in other countries may reveal the occurrence of C. distachya subsp. phyllostachioida there, too. Finally, its occurrence may not be restricted to Eurasia; it may occur also in North Africa, in the countries in which C. distachya subsp. distachya has been recorded (Fig. 1). Both taxa occur in all four countries where we could find C. distachya subsp. phyllostachioidea: Bulgaria, Croatia, Greece, and Montenegro, and also in Türkiye.

Key for identifying the two subspecies of Carex distachya

Leaves 0.5–1.5 mm broad; utricles almost veinless, beak smooth or some utricles with 1–4 tiny

teeth at each beak side ……....………………………….…… C. distachya subsp. distachya

Leaves 0.9–2.5 mm broad, flat; utricles with 2 distinct veins, all beaks scabrid, with more than

4 tiny teeth at each beak side ......................................... C. distachya subsp. phyllostachioidea