| X Duarctopoa labradorica (Steud.) Soreng & L.J. Gillespie | |
| Publ. & Syn. | Arctopoa eminens x Dupontia fisheri. |
| Notes | Elven and Solstad: X Duarctopoa labradorica has for a long time been known from northeastern Canada. Several new localities were found in western Alaska in 2001 and 2003 (ALA, O). This hybrid species has been analysed very thoroughly (Darbyshire et al. 1992; Darbyshire and Cayouette 1992; Cayouette and Darbyshire 1993, 2007a; Gillespie et al. 2008) and is shown to have the proposed origin. It is obviously polyphyletic in the polytopic meaning, but as it spreads independently of its parents and has a distinct range (Labrador, James Bay-eastern Hudson Bay, western Alaska), it is acceptable for inclusion as species in the Checklist. Some Alaskan plants have well-developed anthers and pollen but seed-set has not been investigated. The Dupontia partner in the eastern Canadian subarea seems to be the tetraploid "psilosantha" morph, as indicated also by the chromosome number. In the Alaskan subarea, it co-occurs with the dodecaploid morph, the chromosome number is not known, and the suggested anther fertility may suggest a different evolutionary pathway. Darbyshire and Cayouette (1992) showed that the previous publication of this hybrid genus and species as X Dupontopoa dezhnevii Prob. (in Probatova and Yurtzev 1984) must be rejected because the type sheet contains elements of three different grasses, none of them the hybrid: Arctophila fulva, Leymus mollis subsp. villosissimus, and Arctopoa eminens. The name X Dupontopoa dezhnevii was typified on the Arctopoa shoots and the name is then a synonym of Arctopoa eminens. |
| Chromosomes | 44-46 (ca. 4x). - Canada (NE). - Darbyshire et al. (1992), six counts. |
| Geography | American Beringian & American Atlantic: ALA CAN. |
| Distribution | N = S D = R E = R HL = r AW = r [ key ] |
| Parent taxon | X Duarctopoa Soreng & L.J. Gillespie |
| PAF ID | 343101 |