Panarctic Flora

342901 X Arctodupontia scleroclada (Rupr.) Tzvelev

• Tzvelev, Novosti Sist. Vyssh. Rast. 10: 91 (1973). - Poa scleroclada Rupr., Fl. Samojed. Cisural.: 63 (1845). Holotype (LE!): European Russia: "Malaya Zemlya tundra, ad promont. Sanctum terrae parvae Samojedorum", leg. Ruprecht.
• Arctophila fulva x Dupontia fisheri.

Geography: Circumpolar?: NOR RUS RFE CAN.

Notes: Brysting, Flatberg, Alsos, and Elven: XArctodupontia scleroclada was fairly recently documented from Svalbard (Brysting and Elven 2005) where it now is known with populations in three restricted areas, more or less in the absence of at least one of its presumed parents. In the Ny-Ålesund area (Brysting and Elven), the Dupontia parent seems to be of the "fisheri" morph, i.e., probably octoploid, and here is found dehiscent anthers and well-formed pollen. Dupontia itself is not documented from within the range of Arctodupontia in this area. In the Grønfjorden area (Flatberg), the assumed Dupontia parent is of the "psilosantha" morph, i.e., probably tetraploid. In Prins Karls Forland (Alsos and Elven in 2009), the parental combination is uncertain but the plant is found together with Dupontia of the "psilosantha" morph, occurs in a vast population, and has dehiscent anthers. Inflorescences were collected in the Ny-Ålesund area in September 2009 but were still in a late anthesis stage, without developed fruits. The type collection of Poa scleroclada from northeastern Russia represents this hybrid but is morphologically different from all three Svalbard populations. We provisionally apply the name X Arctodupontia scleroclada for the collective assumed hybrid irrespective of which part of D. fisheri that partakes.

Specimens (LE) supporting occurrence in Chukotka were based on Arctophila fulva. However, Tzvelev and Yurtsev stated (in comment) that there are more specimens and localities. Darbyshire and Cayouette (2007) reported this hybrid from Mansfield Island in the Hudson Bay, Canada, with indehiscent anthers.