1. Carex ×walasii (Cyperaceae) in Western Pomerania
Jacob Koopman & Helena Więcław
Department of Plant Taxonomy and Phytogeography
Institute for Research on Biodiversity
Faculty of Biology, Uniwersity of Szczecin
Fig. 1. Carex  walasii Ceynowa-Giełdoń
Carex  walasii is a very rare, natural hybrid of C. atherodes and C. hirta, recently described by Ceynowa-Giełdoń (1993) from Łowinek, north of Bygdoszcz (Kujawsko-Pomorskie). A visit by the authors of this poster in 2014 revealed that it still grows over there, in a vital population, along a small pond.
This hybrid is closer to C. atherodes than to C. hirta, evidenced by metric traits and the shape of utricles and glumes. Carex  walasii is a tall sedge ( cm high) with hairy leaves, especially beneath and on the sheaths and with entirely pubescent utricles; the latter trait is more similar to C. hirta .
authors (photo P. Kalinowski)
Table 1.Differential characters of C.  walasii, C. atherodes and C. hirta
Characters
Carex atherodes
Carex  walasii
Carex hirta
Stem hight cm cm cm
Stem width at the base
7-10 mm
3-6 mm
3-5 mm
Basal sheaths
fibrous
fibrous or entire
usually entire
Leaf pubescence
sparsely hairy beneath and on the sheaths
hairy, especially beneath and on the sheaths
usually hairy at least on the sheaths
Lenght of female spikes
25-80 mm
25-65 mm
10-45 mm
Lowest bract
usually exceeding the inflorescence
usually equalling the inflorescence
usually shorter than the inflorescence
Utricles
glabrous or sparsely hairy near the apex
entirely pubescent
Utricle lenght
6-9 mm
6-8 mm
5-7 mm
beak lenght mm mm mm
1.A. Inflorescence (photo B. Kurnicki)
1.B. Utricles (photo B. Kurnicki)
Fig. 2. Carex atherodes Spreng.
Carex  walasii has recently been found at three new localities in Żeńsko (ATPOL AC29), Lubiana (AC28) and Storkowo (BB80) in Western Pomerania. At the first site, the hybrid grows on the shore of a small pond with e.g. Phragmites australis, Cirsium arvense and Urtica dioica. Carex hirta grows here in the direct neighbourhood. In the second locality it grows in a wet meadow with species from the Molinio-Arrhenatheretea class. In Storkowo C.  walasii occurs together with C. atherodes occurs in a depression along a small lake.
Worldwide there are so far five localities known (Koopman 2015). Apart from the three mentioned above in Western Pomerania and the locus classicus in Łowinek it has also been found in Germany, in neighbouring Brandenburg (pers. com. M. Ristow, Potsdam) .
2.A. Habitat (photo W. Poelstra)
2.B. Inflorescence (photo G. Grzejszczak)
The range of Carex atherodes (synonym: C. aristata R. Brown, used in older floras) covers North America, North Asia and North-eastern Europe (Chater 1980; Hultén & Fries 1986). In the north, it stretches from Scandinavia through central and southern Russia to Siberia (Egorova 1999). The southernmost sites are situated in Mongolia, China and the Caucasus (Schultze-Motel 1980). In Northern Germany (Sohr & Ristow 1996), it occurs at dispersed locations. It grows in wet meadows, wetlands, along lake shores, ponds, streams and ditches.
Fig. 4. Distribution of C.  walasii in Poland
In Poland Carex atherodes was categorized as vulnerable (Rutkowski 2014; Kaźmierczakowa et al. 2016) and occurs at dispersed locations, usually in the regions of Western Pomerania, Kujawy and Masuria (Zając & Zając 2001).
- Łowinek CB97
new localities
Lubiana AC28
Żeńsko AC29
Storkowo BB80
2.D. Utricles (photo B. Kurnicki)
2.C. Inflorescences (photo W. Poelstra)
Fig. 3. Carex hirta L.
Carex hirta has a wide geographical range covering almost the whole of Europe (Koopman 2015), reaching Iran in the east , Moroco in the south and Scandinavia in the north (Hultén & Fries 1986). It grows in a wide ecological range under diverse habitat conditions − it has been found along roadsides, in grasslands, meadows with varying moisture content, open forests, in and along ditches, along lake shores and river banks. It is morphologically variable, both in the size of characteristics and pubescence, and therefore several forms are distinguished (e.g. Kükenthal 1909). In moist shady places, leaves and sheaths of C. hirta are less pubescent (Jermy et al. 2007). Due to these differences in pubescence, C. hirtiiformis Pers. was described as a separate species with hairless sheaths and leaves, and sparsely hairy utricles, currently considered mostly as a synonym of C. hirta (see Molina et al. 2006).
References
Ceynowa-Giełdon M   Carex ×walasii (Cyperaceae) – a new natural hybrid from northern Poland. Fragm. Flor. Geobot. 38(1):
Chater A. O Carex L. In: T. G. Tutin, V. H. Heywood, N. A Burges., D. M. Moore, S. M. Walters & D. A. Webb (eds.). Flora Europaea, vol. 5 Alismataceae to Orchidaceae (Monocotyledones), pp Cambridge University Press, Cambridge.
Egorova T. V The sedges (Carex L.) of Russia and adjacent states (within the limits of the former USSR). 772 pp. Missouri Botanical Garden Press, Saint-Louis.
Hultén E., Fries M. 1986a. Atlas of North European vascular plants north of the Tropic of Cancer. 3: Koeltz Scientific Books, Königstein.
Hultén E., Fries M. 1986b. Atlas of North European vascular plants north of the Tropic of Cancer. 1. pp. xvii Koeltz Scientific Books, Königstein.
Jermy J., Simpson D. A., Foley M., Porter M Sedges of the British Isles. 554 pp. Botanical Society of the British Isles, London.
Kaźmierczakowa R., Bloch-Orłowska J., Celka Z., Cwener A., Dajdok Z., Michalska-Hejduk D., Pawlikowski P., Szczęśniak E., Ziarnek K Polish red list of pteridophytes and flowering plants. pp. 44. Instytut Ochrony Przyrody Polskiej Akademii Nauk, Kraków.
Koopman J Carex Europaea, The genus Carex L. (Cyperaceae) in Europe 1. Accepted names, hybrids, synonyms, distribution, chromosome numbers. 2nd edition, e-book. Weikersheim: Margraf Publishers.
Kükenthal G Cyperaceae–Caricoideae. In: A. Engler (ed). Das Pflanzenreich. vol. 4 (21). pp Wilhelm Engelmann, Leipzig.
Molina A., Acedo C., Llamas F The relationship between water availability and anatomical characters in Carex hirta. Aquatic Botany 85:
Rutkowski L Carex atherodes Sprengel – turzyca oścista. In: R. Kazimierczakowa, K. Zarzycki (eds.), Polish red data book of plants. pp Instytut Ochrony Przyrody, Polska Akademia Nauk, Kraków.
Schultze-Motel W Carex L. In: G. Hegi (ed.). Illustrierte Flora von Mitteleuropa. Band II. Teil 1. 96–274 pp. Verlag Paul Parey, Berlin-Hamburg.
Sohr S., Ristow M Neue Fundorte von Carex atherodes Spreng. in Brandenburg. Verh. Bot. Ver. Berlin Brandenburg 129:
Zając A., Zając M. (red.) Distribution Atlas of Vascular Plants in Poland. xii Pracownia Chorologii Komputerowej Instytutu Botaniki, Uniwersytet Jagielloński, Kraków.
3.A. Inflorescences (photo P. Kalinowski)
3.B. Utricles (photo B. Kurnicki)