The genus Carex (Cyperaceae) in Slovenia

Jogan et al. (2001) did not distinguish C. aterrima from C. atrata and treated them together in the C. atrata aggregate, while Martinčič (2007) distinguished them on subspecies level. However, nowadays both taxa are regarded as two separate species (Więcław et al., 2017; Roalson et al., 2021). Carex atrata is rather common in Slovenia above 1300 m in the calcareous mountains, while C. aterrima is a rare mountainous species. Carex aterrima used to be known only from the Julian Alps (Martinčič, 2007). However, the second author and T. Čelik have found it also in Kamnik-Savinja Alps, below Mount Tolsti vrh, in June 2008 and together with U. Šilc near Koča na Loki, under Mount Raduha in July 2021.

This species was found in Slovenia in the Krn Mts. (Julian Alps) by Surina (2004, 2005). It was recorded over there from two locations, on the southern slope of Mount Lemež and between the Mts. Veliki Šmohor and Mali Šmohor. However, it had obviously been overlooked, that T. Wraber collected C. austroalpina in Trnovski gozd plateau in Smrekova draga on 27 August 1980.

The occurrence of this species in Slovenia, in the Julian Alps, was doubtful for a long time, as there were no reliable data (Martinčič, 2007). Carex bicolor was first cited for the flora of Slovenia (then Carniola) by Fritsch (1897) and later summarised by Hegi (1908), but there are no detailed data about this species in the above sources. Therefore, Wraber (1983) proposed that C. bicolor should be deleted from the flora of Slovenia. However, Novak (2010) discovered a site near Prehodavci in the valley of Triglav seven lakes, Julian Alps. Anderle & Leban (2014) reported it from a second site, near Lake Zeleno jezero, not far from the first site. Dakskobler & Martinčič (2022) made a phytosociological investigation of both sites and described a new association, Caricetum bicolori-frigidae Dakskobler & Martinčič 2022.

This taxon is not mentioned by Jogan et al. (2001), although Fleischmann (1844) reported it from Begunjščica and Zelenica in Karavanke Alps. The occurrence on these two sites could not be confirmed by recent fieldwork and there is no herbarium material available. Currently there is only one site known of this species in Slovenia, found in 1991 by B. Anderle (Wraber, 2001; Dakskobler et al., 2021b). In July 2020 we visited that site and could confirm the current occurrence of C. brunnescens in Slovenia.

This species was mentioned for Slovenia for the first time by Hayek (1956), which actually refers to the finding of E. Preismann near Slovenj Gradec. Later, Seliškar (1986a) published its occurrence near Sinja Gorica in the vicinity of Vrhnika. Kaligarič et al. (2006) mentioned C. buekii from three sites in the vicinity of the River Mura, and Bakan (2011) found it in Prekmurje. Several other sites found in the last decade, all in the NE part of Slovenia, were published by Koopman et al. (2018). Also, three collections in LJU belong to this species. A. Martinčič collected it near Šmartno near Ljubljana in 1956 (here confirmed and collected by the first author in 2015), Š. Špilak near Murska Sobota in 1974 and B. Trčak near Hotiza in 2016.

Jogan et al. (2001) mentioned this species from four quadrants in Slovenia. Kocjan et al. (2014) made a survey of its sites and the number of known quadrants raised to eight altogether. In 2022 we could confirm its occurrence for Slovenia near Ljubljana, SW from Podutik, as well as on Cerknica plateau, SW from Dolenje Jezero and near Kranjska gora, at Zelenci Nature Reserve. Moreover, there is another new site, previously not published, SW from Grahovo at Cerknica plateau, discovered in 2015 by the first author. This species is often mixed up with C. hartmaniorum (Więcław et al., 2017; Więcław et al., 2021). However, the spikes of C. buxbaumii are more club-shaped and the plant is bluish-green, while C. hartmaniorum has more brownish coloured, cylindrical spikes and the plants are dull green-brown. The material we collected in Zelenci Nature Reserve is intermediate between these two species, although it is certainly not a hybrid, as it is completely fertile (the utricles are full, i.e. with developed nuts).

Martinčič (2007) listed this taxon for Karavanke Alps, which, according to Jiménez-Mejías et al. (2014), refers to A. Paulin’s mention to Križe near Tržič, published in Hayek & Paulin (1907). However, of the Phacocystis section, only C. goodenoughii Gay (= C. nigra (L.) Reichard) is mentioned in Hayek & Paulin (1907) and one of the sites is mentioned Križe near Komenda (not Tržič!), where C. nigra still occurs. There is one more record of C. cespitosa in the vicinity of the village Obrov, Brkini, Primorska region, where it had been recorded by Poldini (1980). This finding is not supported by herbarium material, therefore Jiménez-Mejías et al. (2014) question its occurrence in Slovenia. Carex cespitosa (Figure 1A) has been found on Planina plateau in 2015 (Kocjan, 2016), where it occurs in a relatively large area on the south-eastern side of the River Unica in two quadrants. The site was visited by the authors in 2020 as well as in 2022 to confirm the current occurrence of C. cespitosa in Slovenia. In 2022 we could find a second site, in the Nature Park Radensko Polje, SE of Ljubljana. In the future more sites may be discovered, especially in the NE part of the country, bordering Hungary (Mesterházy & Kulcsár, 2015).

Figure 1 (Slika 1):

A. Carex cespitosa, Radensko polje, 02.06.2022

B. C. depauperata, Dolenji Radenci, 01.06.2022

C. C. diandra, Ljubljana Marshes, 26.05.2022

D. C. dioica, Rakitna, 21.06.2021

E. C. disticha, Planina lake, 01.06.2023

F. C. flacca subsp. erythrostachys, Črni Kal, 27.04.2022

G. C. hartmaniroum, Planina lake, 01.06.2023

H. C. nigra subsp. juncea, Kranjska Gora, 31.05.2022

Photos: J. M. Kocjan

Jogan et al. (2001) mentioned this taxon only from two quadrants in the northwest part of the country. It was found in Slovenia for the first time in the Julian Alps, Vrh Križa, in 1966 (Wraber, 1969). We could confirm its occurrence on a second locality, on mount Mangart in July 2020.

This taxon is not mentioned by Jogan et al. (2001), but it was listed in the Slovenian flora by Martinčič (2007). Carex demissa is actually known from almost the whole country (Kocjan et al., 2014; Kocjan, 2015). We have found it on numerous sites (see Appendix 2).

This species is not mentioned by Jogan et al. (2001), although it was found for the first time in Slovenia in 1997 by Accetto (1998), in the SE of the country, near the border with Croatia. Carex depauperata (Figure 1B) grows there on a steep calcareous slope in old woodland. We found this species in the same wood, but on another site, in 2022. Probably it grows there at more places. Kocjan (2014b) found it in a neighbouring quadrant, S from the village Stari trg pri Kolpi.

This species is mentioned by Jogan et al. (2001) from three sites in the northeast part of the country, which refers to sites discovered by Reichardt (1860) and Murmann (1874). Previously, Pokorny (1858) had found it in the Ljubljana Marshes, between Lavrica and Babna Gorica, Pospichal (1897) found it near Vrtojba, and Druškovič & Sušnik (1976) in the surroundings of Gornji Dolič, Koroška region. There it was found first by T. Wraber in 1975. Currently, it is known from only two sites in Slovenia. In May 2022 the authors could confirm its occurrence on the site in the Ljubljana Marshes, SW of Ljubljana, in the Reserve Iški Morost, where it had been found recently (Kocjan et al., 2017). Carex diandra (Figure 1C) grows here in a small population in a shallow depression in Molinietalia meadows. Despite a thorough search we were not able to confirm its second site, in the NW of Slovenia, in the Nature Reserve Zelenci, near Podkoren, W of Kranjska Gora.

Fleischmann (1844) reported this species from Ljubljana Marshes and near Kočevje, and Murmann (1874) from Lovrenška jezera lakes on Pohorje plateau. Many alleged sites from the second half of the 20^th century were summarised by Bačič (2006), however, there was no convincing herbarium material in LJS nor in LJU. Anderle (2023) published its occurrence in two quadrants in the Julian Alps, however the collected material belongs to C. davalliana. Kocjan et al. (2021) mentioned C. dioica (Figure 1D) from Rakitna, S of Ljubljana, in a wetland on a very wet seepage slope. The site was revisited in May 2022 by us to confirm the currently only reliable site of C. dioica in Slovenia.

Jogan et al. (2001) listed this species only in one quadrant, in the vicinity of Celje, where it was found by J. Zechenter (Maly, 1868). In the past it likely grew in Ljubljana Marshes, e.g. along the River Ižica (Fleischmann, 1844). Recently, C. disticha (Figure 1E) has been found under Šmarna gora near the village Skaručna, where it disappeared soon after, due to changes in the environment (Strgulc-Krajšek 2000). We have seen material from that site in LJU. In 2010 the second author and his coworkers discovered its presence on Planina plain, which is up till now the only known site in Slovenia. In May 2022 we could confirm its occurrence on Planina plain, where it grows in a large population in Molinietalia meadows.

Jogan et al. (2001) reported this species from three quadrants along the seacoast in the southwest of the country and from seven quadrants in the east of the country. As these seven quadrants concern inland records, the occurrence over there seems to be at least doubtful; possibly it had been mixed up with C. praecox. These inland sites were found by J. Zechenter near Celje (Maly, 1868; Hayek, 1956) and by Murmann (1874) near Pobrežje and Dogoše in the vicinity of Maribor and near Miklavž na Dravskem polju, Velika Nedelja and Ormož. In May 2022 we could confirm the occurrence of a small population of C. divisa in the southwest, near Koper, in the Nature Reserve Škocjanski Zatok.

Jogan et al. (2001) mentioned this species from seven quadrants, all situated in the southwest of Slovenia, along the seacoast. Carex extensa has been also reported on several sites around Koper (Glasnović, 2006). In May 2022, we found it near Koper, in the Nature Reserve Škocjanski Zatok. Besides, the first two authors found it on some sites in the Nature Park Sečoveljske soline and in a Mediterranean salt meadow between Sv. Katarina and Sv. Nikolaj in the vicinity of Ankaran. Carex extensa was included in the first edition of the Red list of endangered plants in Slovenia (Wraber & Skoberne, 1989).

Neither Jogan et al. (2001) nor Martinčič (2007) mentioned this subspecies for Slovenia, although it was mentioned in older literature. Pospichal (1897) noted this taxon from sites near Loka under the Karst edge, in Izola and on Mount Čaven. Mayer (1952) included this subspecies as being present in Slovenia. We have found C. flacca subsp. erythrostachys (Figure 1F) on several locations, all in the sub-mediterranean, coastal part of the country.

In subspecies flacca the female spikes are long pedunculate, hanging, and the female glumes are about as long as the utricles, while in subsp. erythrostachys the female spikes are upright, even when the fruits are ripe, and the glumes are slightly longer than the utricles.

Jogan et al. (2001) noted this species in four quadrants, all located in the mountains in the northwest of the country. All sites, known until the late eighties of the previous century, were summarised by Wraber & Skoberne (1989). Carex frigida is now known in total from nine quadrants in Slovenia (Dakskobler, 2003; Dakskobler & Martinčič, 2021). We could confirm its occurrence at the shore of Green Lake in the valley of Seven Triglav lakes, Julian Alps and on Mount Mangart, also Julian Alps.

This species is mentioned by Jogan et al. (2001) from five sites, spread over the country. For the first time it was found south of Maribor, between Limbuš and Razvanje, in 1892, by Murr (1906), who erroneously identified it as C. pilulifera. In recent years, the first author was able to confirm or discover several sites: below Korada mountain in Goriška Brda (from here mentioned by Dakskobler et al., 2021a), at Kuk mountain at Banjšice plateau (here first discovered by Dakskobler, 2005a), on the western bank of the River Sava near Zagorje ob Savi (here first discovered by the second author in 2010) and south of the city of Maribor, in Stražun forest. The second author knows it also from the vicinity of the villages Gornji Zemon and Artviže in Brkini. In May 2022 the authors could confirm its present occurrence near Belsko, NW of Postojna, SW of Ljubljana, where it had been discovered in April 2019 by J. Figelj. It grows here on a south oriented slope, together with C. pallescens and C. tomentosa. Recently, Anderle (2023) published a site near Naklo, Gorenjska region.

This rare mountainous species was mentioned by Jogan et al. (2001) from five quadrants in the northwest part of Slovenia. Recently, it has been discovered on many new sites (Dakskobler et al., 2014; Dakskobler & Surina, 2017). Its occurrence we could confirm on Mount Mangart, where it grows at high altitude in wind-exposed alpine meadows. The only site where it had been found outside the Julian Alps so far is on Mount Štruca in central Kamnik-Savinja Alps. Here it was collected by T. Wraber in 1971, but the finding has probably never been published anywhere.

Jogan et al. (2001) mention this species from nine quadrants in the SW of the country. As a result of a systematic survey in 2012, it was found to be quite common in the southern part of Primorska area, from where many new sites could be published (Kocjan, 2013). Carex halleriana used to grow also in the inner part of the country, near Bled where it was probably found by Beck-Mannagetta (1908), on Paški Kozjak (Reichardt, 1860) and on Šmarna gora (Šuštar, 1998). Despite several attempts, it has later never been found on these three sites, nor in the surroundings of Postojna, from where it had been mentioned by Paulin (1915). In 2022 we saw it on a few sites in Istria.

This species was found for the first time in Slovenia by the first author on the Planina plain in 2015. Later, he recorded this species along the River Nanoščica on several sites, at Cerknica plain and confirmed its occurrence in Žejna dolina valley near Logatec (here first discovered by B. Trčak in June 2020). In the LJU herbarium we found one collection of C. hartmaniorum (Figure 1G), collected in the early years of the 20^th century by A. Gspan near Postojna, erroneously identified as C. buxbaumii. These two species are morphologically similar and are often confused (Więcław et al., 2017); see at C. buxbaumii for the differences.

This mountainous species was mentioned by Jogan et al. (2001) only from the slopes of the limestone Mount Snežnik, E of Ilirska Bistrica, in the Central South of Slovenia. Here it was discovered by A. Paulin (Dolšak, 1936). In July 2022 the authors, guided by B. Surina, were able to confirm its occurrence over there. The site lies at the northernmost border of its overall occurrence and C. kitaibeliana grows mainly in vegetation, described as Edraiantho graminifolii-Caricetum firmae Horvat (1930) 1934 (Surina & Wraber, 2005).

The first record in Slovenia of this species was mentioned by C. Deschmann in 1868 (LJU), who found it in Ljubljana Marshes near Bevke. It was collected on this site for the last time around 1900, as evidenced by the herbarium sheet, stored in LJU (Vreš & Čelik, 2021). With the drying up of Lake Primožičevo jezero as the only known location, the species was considered being extinct (Dolšak, 1936; Mayer, 1952; Wraber, 1972). In the mid-1980s, as part of systematic investigations of minerotrophic bogs, Martinčič (1988) found C. lasiocarpa in the Zelenci Nature Reserve, and later on three other locations: in the Ledine bog on Jelovica plateau, on Bloke plateau near Ulaka village and near Dolenja vas in the vicinity of Ribnica (Martinčič, 1994). We could confirm the presence of C. lasiocarpa on a few sites, at Cerknica plain, where it had been discovered by the first and third author, and also in Ledine bog in Jelovica, in the Zelenci Nature Reserve near Kranjska Gora and twice in Ljubljana Marshes, between Škofljica and Ig, from where it had been published by Čelik et al. (2009). In the vicinity of Lavrica, NE from Hauptmance, from where it had not been known before, it was discovered by the first author in 2021. Later Vreš & Čelik (2021) reported on further findings: in the vicinity of Bevke in Ljubljana Marshes, in Prevojska and Češeniška gmajna woods and under the village Dobeno SW from Mengeš. The second author and T. Čelik found also new sites of this species on Cerknica plain in 2023.

Although it was probably first mentioned for Slovenia by Mayer (1952), Jogan et al. (2001) did not record this species. Trčak (2006) revised all available herbarium sheets of the Carex muricata agg. from Slovenia and noted that it occurs only on a few sites scattered over the country. Bakan (2011) added two more sites from the NE part of the country. In 2019 the first and third author found it near Črni Kal in Istria. In 2022 the authors saw a few clumps of this species in Škocjanski zatok Nature Reserve near Koper.

Although shown for 13 quadrants by Jogan et al. (2001), C. limosa is one of the rarest and most endangered carices in Slovenia, confirmed since 2000 in not more than nine quadrants (Kocjan, 2012). Since then, it has very likely disappeared from the foothills of Rožnik in Ljubljana (Kocjan & Kosič Kocjan, 2021) and also, together with Comarum palustre and Liparis loeselii, from the site near Komenda due to the expansion of the industrial complex. It has first been found here less than 20 years ago. We could confirm its existence on Pokljuka and Jelovica plateau in 2020, Julian Alps, and in Zelenci Nature Park in 2022.

Jogan et al. (2001) mentioned it from two quadrants of which one refers to the finding of Paulin (1915) in the vicinity of Črnuče, N of Ljubljana. We have not found the original source for quadrant 9459/1, however J. Zech-enter found it near Celje (Hayek, 1956; we have seen the herbarium specimens). More recently, it has also been found on several other sites: Krško-Brežice plain (Frajman et al., 2009), in Soča valley, Julian Alps (Dakskobler, 2009, 2011) and near Šempas in Vipavska dolina valley (Kocjan, 2013). In 2009, the second author and A. Seliškar found it near Zgornji Obrež, NE Slovenia. Despite these findings it is still very rare in Slovenia as there are not so many suitable habitats. In May 2022 we could confirm its occurrence in Slovenia on the left bank of the River Sava, N of Ljubljana.

Its known distribution in Slovenia was limited to Mount Mangart in the W Julian Alps and Mount Stol in the Karavanke Alps, from where the site was published by Dolšak (1936). Wraber (1960) published two new sites in the Julian Alps, Novak (2012) found a second site in the Karavanke Alps, on Mount Košuta and later on Mount Spodnja Vrbanova špica in the Julian Alps (Novak, 2015). Dakskobler & Surina (2017) significantly contributed to the knowledge of the distribution of this species in the Julian Alps, as they have published 47 phytosociological relevés from numerous sites and described a new association: Achilleo clavennae-Elynetum myosuroidis Dakskobler & Surina 2017. Recently, it has been found on Mount Begunjščica in the Karavanke Alps (Anderle, 2023). In July 2020 the authors could confirm its occurrence on Mangart.

Neither Jogan et al. (2001) nor Martinčič (2007) mentioned this subspecies for Slovenia. For the first time we have found C. nigra subsp. juncea (Figure 1H) in Zelenci Nature Reserve in 2022. Later two new sites in Gorenjska region were found, in Ledine bog on Jelovica plateau and in a marsh above the village Nemški Rovt under the same plateau (Kocjan & Kosič Kocjan, 2023). In addition, we found one collection of this subspecies in the LJU herbarium, collected by T. Wraber, erroneously identified as C. elata.

Jogan et al. (2001) provided a distribution map for the entire C. ornithopoda agg. According to Martinčič (2007) the subspecies ornithopodioides grows in Slovenia only in the Julian Alps. However, it had previously been found on Mount Ojstrica in the Kamnik-Savinja Alps by Hayek & Paulin (1907). Lately it has been recorded also from the Karavanke Alps and discovered on new sites in the Kamnik-Savinja Alps (Frajman et al., 2006). Leban et al. (2011) published numerous new sites from the Slovenian Alps and discussed the latest knowledge on the overall distribution in Slovenia. In several relevés, published by Surina & Dakskobler (2017), one can also find a few new sites of this subspecies. The overall distribution for Gorenjska region was presented by Anderle (2023). In 2018 the first author found a site in Štajerska region, while in 2021 the second author and U. Šilc found this taxon on the same plateau on Mount Veliki vrh. The first author also found one specimen of C. ornithopoda subsp. ornithopodioides in LJU, which N. Praprotnik had collected in the Karavanke Alps.

Carex ornithopoda subsp. ornithopodioides differs from the closely related and similar C. ornithopoda subsp. ornithopoda in having shorter, entirely glabrous utricles, very curved stems, shorter female spikes and blackish-purple glumes.

According to Jogan et al. (2001) this species occurs in Slovenia on Pohorje, Jelovica and Pokljuka plateaus, and near Kranjska Gora. However, the site in Zelenci Nature Reserve is erroneous, while Wulfen (1858) found it also in the Ljubljana Marshes in the second half of the 18^th century. We do not find any notions of it from this area in the 19^th century or later, therefore it must have been extinct here already in the late 18^th century. Nevertheless, we could confirm its presence on all three previously mentioned mountain plateaus in 2020.

More than two decades ago it was still known from only ten quadrants in Slovenia (Jogan et al., 2001). We now know that this species is more widespread, although it should still be considered as rare. In the last few decades several new sites from different regions have been published (Bakan, 2006, 2011; Šilc & Košir, 2006; Dakskobler et al., 2007, 2011; Stergaršek & Jogan, 2010; Anderle, 2023; Dakskobler et al., 2025).

In both editions of the Red list of endangered plants of Slovenia (Wraber & Skoberne, 1989; Wraber et al., 2002) this species is treated as rare. Until 1989 only six sites were known, of which the last had been confirmed in 1968. Jogan et al. (2001) mentioned it from eight sites, while Kocjan (2014a) published a distribution map, where this species is recorded from 15 quadrants. Carex punctata can be found among others in Molinietalia meadows in Ljubljana Marshes, S of Ljubljana. The second author and B. Dolinar found it in the valley of the River Kolpa between Grivac and Kuželj in 2014. Its occurrence over there could be confirmed by the authors in July 2020, in the Reserve Iški Morost, as well as in May 2022, W of this reserve. On both sites it was found first by the second author and U. Šilc in 2015. In May 2021, the first author found a site in Kižlovka valley N of Podlipoglav, SE of Ljubljana, near the valley of Podmolniški graben W of Podmolnik and in May 2024, he found it NW from Dolenja vas pri Polhovem Gradcu.

Although Jogan et al. (2001) mentioned only three quadrants for this species in Slovenia, C. randalpina is much more common, as shown by Kocjan (2016) and as we have noticed during fieldwork. It can be found in particular in Alnus forests and in wet meadows, bordering forests, rivers and streams. The first author and A. Jakob discovered a new site near Mislinjska Dobrava, SE from Slovenj Gradec in 2016, which lies more than 50 km from the closest known site in the country. Very likely it might also be found in the eastern regions of Slovenia, since we know sites from the vicinity in both Hungary (Mesterházy et al., 2011) and Croatia (Koopman et al., 2026).

Jogan et al. (2001) mentioned this species for eight quadrants. Many new sites have been discovered in the Julian Alps, Kamnik-Savinja Alps, and in Karavanke Alps more recently (Dakskobler, 2003; Frajman et al., 2006; Dakskobler & Frajman, 2007; Dakskobler et al., 2008; Anderle & Leban, 2011; Novak, 2012; Dakskobler & Surina, 2017). Besides growing in the Alps, it is also known from Mount Snežnik in the Dinaric mountains (Wraber, 1965; Wraber, 1966; Surina & Wraber, 2005).

Jogan et al. (2001) mentioned this species from three quadrants in the northeast of Slovenia. Its current distribution in Slovenia is presented by Trčak & Bačič (2017), since many new sites along the River Mura have been discovered. This forest species was found by the authors in an old forest reserve, Krakovski pragozd, SE Slovenia, in 2022, where it grows together with C. sylvatica, C. remota and abundantly C. pendula. Along the River Mura it grows particularly in riparian forests with Alnus glutinosa, Fraxinus excelsior and Salix alba and in mixed oak-elm-ash forests (Trčak & Bačič, 2017), while in Krakovski gozd we found it in Quercus robur forest.

This hybrid is relatively not very rare in Slovenia, like in other European countries, where it usually grows together with its parental species (see Jermy et al., 2007; Więcław & Wilhelm, 2014; Koopman & Więcław, 2019). Dakskobler et al. (2011) published a few sites with C. × alsatica in the basin of the River Idrijca. Kocjan et al. (2021) and Kocjan & Kosič Kocjan (2023) mentioned C. × alsatica on various sites across central Slovenia and on Jelovica plateau. Most of these sites were confirmed during our fieldwork (see Appendix 2).

Carex × alsatica is morphologically intermediate between the parents, or more similar to C. flava (Więcław & Wilhelm, 2014).

It was found for the first time in Slovenia in 2019 by the first author, near the Biological Centre in Ljubljana, together with both rhizomatous growing parents. This hybrid was still growing there in 2022; moreover, the authors found a new site on Radensko polje plain. Kocjan & Kosič Kocjan (2021) found C. × auroniensis (Figure 2A) in Nature Park Tivoli, Rožnik and Šišenski hrib. Aside from Slovenia this hybrid is known from nine other European countries (Koopman, 2022).

Figure 2 (Slika 1):

A. Carex × auroniensis, Ljubljana, 15.05.2021

B. C. × muelleriana, Ljubljana Marshes, NR Iški morost, 27.06.2021

C. C. × oberrodensis, Grosuplje, 02.06.2021

D. C. × ruedtii, Ljubljana Marshes, 03.07.2021

E. C. × subviridula, Nemški Rovt, 12.06.2022

Photos: J.M. Kocjan

This is possibly the most common Carex hybrid in Europe (see Koopman, 2022), but probably often overlooked. Both the parental species are rather similar in appearance, which causes that material (including the hybrid) has often been identified erroneously in herbaria as well as in the field. It holds in its characters perfectly the middle of the two parents: it is too tall for C. nigra, too small for C. acuta. However, as C. acuta has, like most carices, stomata on the back side of the leaves and C. nigra, exceptionally, on the upper side, the hybrid has, as a consequence, stomata on both sides, easily to see with a loupe on fresh collected material or in the field (see Wallnöfer, 2006; Jermy et al., 2007)

In Slovenia, Dolšak (1936) published a transcript of a herbarium label of material collected and determined as C. × elytroides by A. Paulin behind Rožnik in Ljubljana. Kocjan & Kosič Kocjan (2021) found this hybrid in Nature Park Tivoli, Rožnik and Šišenski hrib. Carex × elytroides was also recorded on various sites on Jelovica plateau (Kocjan & Kosič Kocjan, 2023).

This hybrid is quite frequently recorded in Europe (Koopman, 2022), usually on sites where the parent species co-occur (Jermy et al., 2007; Więcław & Koopman, 2013; Koopman & Więcław, 2019). It forms loosely caespitose plants, with straw-coloured inflorescences. Like in C. demissa the lowest female spike is often somewhat remote, halfway the flowering stem. Specimens of C. × fulva have a characteristic whitish stigma base extended from the utricle beak and a broad scarious margin at the female glume like C. hostiana (Więcław & Koopman, 2013). In Slovenia it is probably not rare, but it might be overlooked.

This hybrid has been listed in many European countries (Koopman, 2022). It differs fom both parental species in the stomata, which occur on both sides on the leaf; C. vesicaria has stomata on the back side of the leaves and C. rostrata on the upper side.

Vreš et al. (2013) published two sites in Slovenia, while the first author found it in the vicinity of Horjul in 2016.

This hybrid is not rare in Slovenia and it usually grows together with its parental species. Carex × leutzii was reported by Dakskobler et al. (2011) from the basin of the River Idrijca, by Dolinar & Vreš (2012) from Mišja dolina valley near Velike Lašče, by Vreš et al. (2013) mainly from Bloke plateau, by Vreš & Čelik (2021) from Ljubljana marshes, by Kocjan et al. (2021) from various sites across central Slovenia, and by Kocjan & Kosič Kocjan (2023) from various sites on Jelovica plateau.

Carex × leutzii is morphologically intermediate between the parents, or more similar to C. hostiana, also with a white membrane at the beak apex and with a broad scarious margin at the female glumes (Więcław & Koopman, 2013), and the hybrid is probably often mistaken for it. Such mistakes are especially likely during the early stages of their development, when the utricles are not yet fully developed (Więcław & Koopman, 2013).

This rare hybrid was recognised for the first time in Slovenia by the first author in Ljubljana Marshes, W from Iški morost Nature reserve in 2021, and confirmed, albeit tentatively, on the same site in May 2022. After the revision of herbarium material in LJU, another locality was confirmed. A. Podobnik collected this taxon in 1986 close to the village Veliki Otok near Postojna. Apart from Slovenia, it is mentioned from nine other countries in Europe (Koopman, 2022).

Carex × muelleriana (Figure 2B) differs from C. hostiana in the longer male spikes and bracts, while from C. distans in its longer, pale green leaves, its greyer basal sheaths and the hyaline margin of the glumes (Jermy et al., 2007).

In Europe, this hybrid had been reported from three countries so far, Austria, Italy (Koopman, 2022) and Croatia (Koopman et al., 2026). In Slovenia it is known from four locations: in the valley of Črna dolina (Kocjan et al. 2021), W from Malo Mlačevo near Grosuplje, SE from Horjul, and between Dvor pri Polhovem Gradcu and Dolenja vas W of Ljubljana. The tussocks of Carex × oberrodensis (Figure 2C) are much bigger than those of C. elata, and the broad and shining leaves show clearly its relationship to C. randalpina, which grows on all four sites in the direct neighbourhood.

This hybrid has been noted in five European countries: Austria, Germany, Italy, and Slovenia (Koopman, 2022) and Croatia (Koopman et al., 2026). Carex × oenensis is morphologically intermediate between the parents. It is a tall plant, like C. randalpina, forming large mats, but the dull coloured leaves are narrower than the glancing ones of C. randalpina (see Wallnöfer, 1992).

This hybrid has first been found in Slovenia by J. Figelj on one site, in 2023. Apart from Slovenia, it is known from eight other countries in Europe (Koopman, 2022).

Carex × ohmuelleriana is morphologically rather intermediate to its parents. The lower, remote spikes, sometimes with an elongated bract, are reminiscent of C. remota, the top of the inflorescence, more compact, is reminiscent of C. brizoides, as is the silvery colour of the inflorescence. It differs from C. remota in its rhizomatous growth, from C. brizoides in its long lower bracts and elongated inflorescence (Koopman, 2018).

This hybrid has first been found in Slovenia SW of the village Ribno near Bled by the first author and V. Leban, and subsequently by the authors on Cerknica plain, together with the parental species.

Carex × pauliana is morphologically rather intermediate to its parents. It is a relatively small plant (stems up to 25 cm) and has a utricle beak less than 1 mm long with a white membrane at the apex (a character inherited from C. hostiana) (see Koopman & Więcław, 2019).

This hybrid has been listed in many European countries (Koopman, 2022). In Slovenia, three localities are known so far (see Appendix 2).

Carex × prolixa has long thin male and female spikes inherited from C. acuta, while the short lowest bracts and pale coloured, somewhat fibrillose basal sheaths are inherited from C. elata (Jermy et al., 2007).

Carex material, stored in LJU as C. elongata clearly represents the hybrid between C. otrubae and C. remota. The material was collected by A. Martinčič, in the NE part of Slovenia, close to the settlement Središče ob Dravi in 1955.

Carex × pseudoaxillaris differs from C. otrubae in its more slender stems, its rounded ligule, its distinctly separated spikes and its long lowest bract that often exceeds the inflorescence. From C. remota it can be distinguished by its wider leaf blades, its much stouter, triangular, brownish spikes and shorter distance between the two lowest spikes (Jermy et al., 2007; Koopman et al., 2023).

This hybrid was first found in Slovenia by the authors in Zelenci Nature Reserve, together with both parents, in a wetland, in May 2022.

Carex × rotae differs from C. paniculata by its larger appearance, darker, a bit more fibrous basal sheaths, and shorter and stiff inflorescences. From C. appropinquata it can be distinguished by its dark brown, slightly fibrous basal sheaths and by its occasionally extremely long inflorescences (Jermy et al., 2007).

It is thought to have been found in Slovenia for the first time in the vicinity of Maribor by J. Murr (Hayek, 1956), however we have not seen the material, providing it exists. Nevertheless, we have found Carex × ruedtii (Figure 2D) on several locations: in the Nature reserve Zelenci, under Mount Šmarna gora N of Ljubljana, near Horjul W from the village Lesno Brdo, in Babni dol in the municipality Medvode and in Ljubljana Marshes not far from Iški morost nature reserve. Sites in the Ljubljana marshes near Ig were first published by Vreš & Čelik (2021).

This hybrid often grows together with both parents. It resembles mostly C. lepidocarpa, generally also with two female spikes, but the straw-coloured inflorescences when ripe and the usually empty utricles are distinctive (Więcław & Wilhelm, 2014).

We currently know this hybrid from several sites in Slovenia (see Appendix 2). In 2022 the authors could confirm it still grows in Besnica valley E from Ljubljana.

Specimens of C. × schatzii are usually intermediate between both parental species or more similar to C. lepidocarpa; however, the hybrid is smaller than C. lepidocarpa and has straw-coloured inflorescences (Więcław & Wilhelm, 2014).

This hybrid has been recorded in 11 European countries (Koopman, 2022). In Slovenia, C. × strictiformis has recently been found by the authors on two sites: on Planina plain in 2020 and on Radensko polje plain in 2022.

In Slovenia, we have found this hybrid on three localities so far: near Nemški Rovt under the Jelovica plateau, Julian Alps, near Zgornje Bitnje in the vicinity of Kranj, and E from the village Ulaka on Bloke plateau.

Carex × subviridula (Figure 2E) is morphologically intermediate between both parental species or more similar to a tall C. oederi (Więcław, 2014).

It had been found for the first time in Slovenia by the second author and U. Šilc in Ljubljana Marshes, between the villages Tomišelj and Lipe in April 2015. We could confirm its occurrence in Slovenia in the Julian Alps, on Jelovica plateau, in July 2020, where we found it in Ledine bog, together with both parents.

Carex × turfosa differs from C. nigra in its broader leaves, usually taller stems, fibrillose basal sheaths, less slender spikes and beaked utricles. From C. elata it differs in its generally less-tussock-forming habit and longer lowest bract. This hybrid has stomata on both sides on the leaves, while C. elata has stomata on the back side of the leaves and C. nigra on the upper side (Jermy et al., 2007).

This is a tall, loosely caespitose hybrid, with a typically yellowish colour, growing in particular in Molinietalia meadows, often rather abundant. In Slovenia, it is not a rare hybrid and on many places it is more common than either of the parents. Mezzena (1986) mentioned two sites with C. × xanthocarpa near Nova Gorica, collected by C. Zirnich around 1950. Kocjan & Kosič Kocjan (2021) found C. × xanthocarpa in Nature Park Tivoli, Rožnik and Šišenski hrib. Kocjan et al. (2021) and Kocjan & Kosič Kocjan (2023) mentioned C. × xanthocarpa for central Slovenia and Jelovica plateau, respectively.

Carex × xanthocarpa is intermediate between both parental species. It has a relatively tall stem, broad female spikes, bracts and leaf blades which are similar in size to those found in C. flava. Specimens of C. × xanthocarpa have a characteristic whitish stigma base extended from the utricle beak and a broad scarious margin at the female glume like C. hostiana (Więcław & Koopman, 2013).