Panarctic Flora

410720 Rumex krausei Jurtz. & V.V. Petrovsky

• Jurtz. & V.V. Petrovsky, Bot. Zhurn. 58: 1745 (1973). Holotype (LE!): Russian Far East: East Chukotka, Zaliv Lavrentiya, 16. July 1971, leg. N. Sekretareva. - Acetosella krausei (Jurtz. & V.V. Petrovsky) Á. Löve & D. Löve, Bot. Not. 128: 506 (1976).

2n= 21 (3x). - Far East (N). - Zhukova and Petrovsky (1971, 1972); Zhukova et al. (1973). Two reports for R. graminifolius var. subspathulatus.

Geography: Amphi-Beringian: RFE ALA.

Notes: Petrovsky and Elven: Acetosella plants are obligately outcrossing (dioecious). The triploid chromosome number of 2n = 21 found in all counted plants of Rumex krausei is therefore very strange. The voucher plants (LE) show no sign of sterility in pollen or fruits. Also the Alaskan plants annotated as R. krausei (ALA) seem to be fertile. This mystery remains to be solved.

Murray and Elven: Rumex krausei is a distinctive plant with basal leaves relatively few, evenly narrow, and mostly distinctly succulent, ochreas conspicuously large, broad, and brownish, stems strongly red pigmented, inflorescence constituting mostly much less than 50% of stem length and unbranched or with 1-2 short basal branches and an uninterrupted terminal part, and flowers larger than in its relatives. It often grows in wet sites, usually seepage on calcareous bedrock (a very uncommon site type for other taxa of Acetosella which often are rather xerophytic and acidophilous). It is a rare and narrowly amphi-Beringian species in East Chukotka and western Alaska where it has been much overlooked.

Murray: Den Nijs (1983), when addressing the existence of R. beringensis and R. krausei, suggested (but we do not think he had seen any material of either taxon) an affinity to the more southern R. pauciflorus and to R. graminifolius s. lat. As shown by Mosyakin (2005), R. pauciflorus Nutt. is a very different thing and assigned by him to subg. Acetosa.