Ludwigia brevipes

Raab-Straube, Eckhard von & Raus, Thomas, 2024, Euro + Med-Checklist Notulae, 17, Willdenowia 54 (1), pp. 5-45 : 26

Ludwigia brevipes (Britton & al.) Eames

(≡ Ludwigiantha brevipes Britton & al.)

– Fig. 13.

A Cm: Crimea: Sevastopol, coast of Streletskaya Bay, 44°35'37"N, 33°28'11"E, 1 m, wasteland on ruins of ancient manor, 1 Sep 2022, Yevseyenkov (photo: https:// www.plantarium.ru/page/image/id/741947.html); ibid., 4 Sep 2022, Yevseyenkov (photo: https://www.plantarium.ru/page/image/id/742251.html); ibid., 20 Sep 2022, Yevseyenkov (photo: https://www.plantarium.ru/page/image /id/744223.html); ibid., 20 Sep 2022, Svirin (photos: https://www.inaturalist.org/observations/153577017 as L. repens J. R. Forst. ); ibid., 28 Sep 2023, Yevseyenkov (YALT; photo: https://www.plantarium.ru/page/image /id/781950.html).

– The native range of Ludwigia brevipes is SE North America ( POWO 2023). Its natural habitats are shores of seasonal ponds and shallow waterbodies, marshes, moist dune hollows and edges of impoundments and ditches. The species is widespread as an ornamental aquatic plant, especially in aquarium keeping. It is listed as an alien invasive species for Great Britain ( CABI 2023). There is no information about records of L. brevipes in other European countries. In Crimea, Ludwigia was first found in 2021 by one of the authors (SAS), and in 2022 it was independently rediscovered in the same habitat by the second author (PEY). The species was originally identified as L. repens . A more thorough study showed that the plants were morphologically closer to L. brevipes , which differs from L. repens in its narrower leaf blades, larger flower parts, sepals 2–3 times longer than wide (vs approximately equally long and wide) and significantly longer fruiting pedicels. Both species belong to the same hybridogenic complex, are hexaploids and have the same genome composition ( Liu & al. 2020). The plants we found have morphological and morphometric characters intermediate between typical L. brevipes and L. repens . The length: width ratio of the sepals of 2: 1. Clearly visible and persistent petals and the presence of relatively long fruiting pedicels allow us to consider the Crimean plants as L. brevipes , although it is possible that they belong to the hybrid L. brevipes × L. repens . The only known locality of this taxon in the city of Sevastopol is the territory of the archeological monument, rural estate No. 101A, of the khôra of the ancient Tauric Chersonese. The plants grow in two soil-filled pithos holes cut into the limestone rock. Currently, the population includes about 100 individuals forming dense mats and covering an area of 1–1.5 m 2. Ludwigia L. is a new genus for the flora of Crimea; only one species of this genus, L. palustris (L.) Elliott, is native to Europe (Raab-Straube 2018+c). The same species was considered the only representative of Ludwigia in the flora of E Europe, where it is reliably known only from Ukrainian Transcarpathia ( Prokudin 1987; Skvortsov 1996). Therefore, L. brevipes is the second species of this genus in E Europe, and to our knowledge the first report of this species for mainland Europe as a whole.

S. A. Svirin, P. E. Yevseyenkov, L. E. Ryff

Figures

Fig. 13. Ludwigia brevipes – A: flowering branches; B: flower; C: fruiting branch. – A: Crimea, Sevastopol, 1 Sep 2022; B: ibid., 20 Sep 2022, photographs by P. E.Yevseyenkov; C: ibid., 20 Sep 2022, photograph by S. A. Svirin.