Panarctic Flora

320101 Juncus biglumis L.

• L., Sp. Pl.: 328 (1753). Lectotype (LINN): Sweden: "Lapland". Herb. Linn. 449.33 (Kirschner in Kirschner et al. 2002b: 112).

2n= (1) 60. - Europe (Norway). - Knaben and Engelskjøn (1967); Schönswetter et al. (2006).
(2) ca. 100 >100. - Siberia (S), Far East (N), Alaska. - At least four reports.
(3) 120. - Europe (N, C), Canada, U.S.A., Greenland. - Several reports.
(4) ca. 130. - Canada (Melville Island). - Mosquin and Hayley (1966) as 2n = 130±10, 'adjusted' by Löve and Löve (1975a) to 2n = ca. 120.

Geography: Circumpolar-alpine: ICE NOR RUS SIB RFE ALA CAN GRL.

Notes: Schönswetter and Elven: There might be some interesting unexplored variation in the widespread arctic-alpine species Juncus biglumis. Three or four chromosome numbers are reported and two major levels are documented from Scandinavia (2n = 60, 120). Scandinavian plants differ from the majority of the arctic plants in size (smaller) and perhaps in some details. Initial molecular studies (AFLP; Schönswetter et al. 2006) show a large and strange geographical pattern, by the authors proposed as three clades, one restricted to Taimyr and with a fourfold larger genomic size than the two others. A few chromosome number reports suggest that the two other clades represent, respectivelly, 2n = 60 and 2n = 120 plants, and that both co-occur in, e.g., eastern Greenland and Svalbard. The authors suggest that the three clades represent distict gene pools and act as cryptic species. Something to do for someone in the future.