| Rorippa palustris (L.) Besser | |
| Publ. & Syn. | Rorippa islandica auct., non (Oeder ex Murray) Borbás (1900). |
| Notes | Rorippa palustris is not very polymorphic in Eurasia (subsp./var. palustris) but much so in North America. Numerous species and races have been described, named, and subsequently accepted by authors (e.g., Hultén in numerous works; Jonsell 1968). Hultén and Fries (1986) reported the following races to reach or nearly reach the Arctic: (a) var. williamsii as the nearly exclusive race of northwestern North America but also with scattered records from the coasts of Hudson and Ungava bays and a single record from interior Chukotka; (b) subsp. fernaldiana from central and eastern North America and as rare on the coasts of James and Hudson bays; (c) subsp. hispida from mainly the same area and reaching northern Labrador; and (d) subsp. occidentalis (S. Watson) Abrams (or rather R. curvisiliqua (Hook.) Bessey ex Britton) from southwestern North America but with an isolated record from non-arctic southwestern Alaska (mapped by Hultén and Fries 1986 as very restricted in Alaska compared with Hultén 1968a). Hultén (1968a) interpreted subsp. fernaldiana as formed through introgression between R. "islandica" (probably R. palustris var. williamsii) and R. hispida but there is no supporting molecular evidence for this hypothesis. Rollins (1993) accepted the North American races as three varieties. Mulligan (in comment) is reluctant to accept any races. However, the obviously larger variation in North America compared with Eurasia merits some treatment. Al-Shehbaz (2010c) accepted subsp. palustris and subsp. hispida, included "fernaldiana" in subsp. palustris, but did not mention "williamsii". We enter two subspecies and comment on Hultén's and Jonsell's additional proposed races under subsp. palustris. |
| Chromosomes | 32 (4x). - See races. |
| Geography | Circumboreal-polar. |
| Distribution | N = F AN = s AO = r GW = * D = ? E = S CC = r YG = r HL = r FN = r CE = r CS = r UN = s YK = r AW = s Kh = r CW = r Tm = r KP = s [ key ] |
| Parent taxon | Rorippa Scop. |
| Child taxa |
Rorippa palustris subsp. hispida (Desv.) Jonsell Rorippa palustris subsp. palustris |
| PAF ID | 671304 |