Carex x vratislaviensis Figert, Allg. Bot. Z. Syst. 6: 39 (1900) [C. acuta x C. buekii].

Wieclaw, Helena, Řepka, Radomir & Koopman, Jacob, 2023, Lectotypification of two names of Carex buekii hybrids (Cyperaceae) and notes on their morphology, ecology and distribution, PhytoKeys 236, pp. 179-186 : 179

Carex x vratislaviensis Figert, Allg. Bot. Z. Syst. 6: 39 (1900) [C. acuta x C. buekii].

Carex buekii melanostachya ≡ C. buekii Wimmer var. melanostachya R. Uechtr., Jahresber. Schles. Ges. Vaterl. Cult. 43: 236 (1865, publ. 1866).

Lectotype (designated here).

Poland. Flora von Schlesien. Liegnitz: Parchwitz, auf Wiesen an der Katzbach unter den Stammarten. 10/6/99. Leg. Figert (WRSL barcode WR GS 066847; isolectotypes: WRSL barcode WR GS 058739; JE barcode JE 00021673, barcode JE 00026167, barcode JE 00026168, barcode JE 00026169) (Fig. 2 ).

Morphology.

This hybrid is very variable, often intermediate between the parental species, but also tends to be morphologically closer to one of the parents. The utricles are very different in shape and size, from small ones similar to C. buekii , to more often closer in size to C. acuta . The leaf sheaths vary with the gene flow of the parental species: from reddish brown, robust, scale-like, shiny, reticulate, to intermediate types with smaller and slender sheaths than C. buekii , dark reddish brown, in spring with distinctive reticulate sheaths and in summer without. In the field, this hybrid is striking for its vegetative traits being close to C. acuta , but it has narrow and long female spikes (longer than those of C. acuta ), especially the lowest one, which is pedunculate, interrupted at the base down to individual flowers and often pendent. The lowest bract sometimes exceeds the inflorescence, a character inherited from C. acuta ( Koopman et al. 2018), but it is often shorter than, or as long as, the inflorescence. Carex x vratislaviensis is usually partially or fully fertile, less often sterile. In the field, backcrosses from the hybrid swarm are fertile and their traits match the variability of either parent. These plants are morphologically indistinguishable in the field from parental species. The only distinctive trait of this hybrid is the persistent small or larger red-brown scale-like basal sheaths.

Ecology.

Both parental species are relatively commonly found, most often in the floodplains of large rivers, where both find suitable habitats ( C. buekii : gravel-sand terraces covered with clay and littoral embankments; C. acuta : oxbows, reservoirs, eutrophic wetlands in floodplains with nutrient-rich sediments) ( Kaplan et al. 2018). Most localities of C. x vratislaviensis correspond with the distribution of C. buekii , however, it was also found on banks of lakes and in adjacent marshes where C. acuta usually grows ( Koopman et al. 2018). Řepka (2023) recently described large populations of the hybrid on the banks of the River Elbe near the town of Děčín (northern Bohemia), and at the edge of the field, a unique habitat completely outside the requirements of both parental species.

Distribution.

It has been recorded so far in Austria, Czech Republic, Germany, Hungary, Italy, Poland, and Slovakia ( Koopman 2022).

Carex x vratislaviensis is an independent hybridogenous taxon (nothospecies) living autonomously in nature, mostly fully or partially fertile, and spreads spontaneously in the landscape. In the Czech Republic, it is currently documented in approximately 400 extensive populations. Based on current knowledge, it is now the most abundant hybrid (nothospecies) of the genus Carex in the Czech Republic. It has an excellent ability of clonal reproduction, and its utricles are spread by water birds to other habitats. At some habitats, especially in older meadows in the floodplains of large rivers, it can strongly dominate over the parental species or grow completely independently without their presence. In our opinion it can be compared with the hybridogenous C. recta Boott, also from the section Carex Phacocystis , which has originated from hybridisation between C. aquatilis Wahlenb. and C. paleacea Schreb. Ex Wahlenb. ( Standley 1990). It is presumed that C. x vratislaviensis influences other species and hybrids by its gene flow and forms triple hybrids or at least simply affects their fertility in situ (and the subsequent formation of empty utricles and thus empty spikes); however, this process needs further research.

Figures

Figure 2. The lectotype of Carex x vratislaviensis Figert (WRSL barcode WR GS 066847). Photo: Herbarium, Museum of Natural History University of Wroclaw, Poland.