Sabulina stricta (Sw.) Rchb.

Gillespie, Lynn J., Saarela, Jeffery M., Sokoloff, Paul C. & Bull, Roger D., 2015, New vascular plant records for the Canadian Arctic Archipelago, PhytoKeys 52, pp. 23-79 : 43-44

Sabulina stricta (Sw.) Rchb.

Minuartia stricta (Sw.) Hiern

Common name.

Bog stitchwort

Distribution.

Circumpolar-alpine

Comments.

This species was first recorded for the western CAA, on southern Victoria Island, by Thannheiser et al. (2001; no voucher collection located), and is confirmed by our collection. The species is known from Baffin, Southampton, and Coats Islands in the eastern Arctic Islands, and has a scattered distribution across the low Arctic (and north-west alpine areas) from Alaska to Labrador and Greenland. On mainland Nunavut it is currently known only from the Hudson Bay area, and in the Northwest Territories from the vicinity of Great Bear Lake and the Hornaday River ( Porsild and Cody 1980, Saarela et al. 2013a). The Victoria Island collections represent a range extension of ca. 400 km northeast of the Northwest Territories populations and ca. 1000 km west of the closest Nunavut population.

This species was previously known as Minuartia stricta (Sw.) Hiern (e.g., Porsild and Cody 1980, Rabeler et al. 2005, Aiken et al. 2007) (the name Sabulina stricta (Michx.) Small ex Rydb., based on Arenaria stricta Michx. [= Sabulina michauxii (Fenzl) Dillenb. & Kadereit, a non-Arctic species], is an illegitimate homonym). Recent molecular studies have determined Minuartia to be polyphyletic ( Harbaugh-Reynaud et al. 2010, Greenberg and Donoghue 2011, Saarela et al. 2013b, Dillenberger and Kadereit 2014). The most comprehensive sampling of the genus was conducted by Dillenberger and Kadereit (2014), who proposed a new classification of the group. The clade to which Minuartia stricta belongs ("clade 10") has been segregated as a distinct genus, Sabulina Rchb., with 65 species. Sabulina includes four other Canadian Arctic species: Sabulina dawsonensis (Britton) Rydb. [syn. Minuartia dawsonensis (Britton) House], Sabulina elegans (Cham. & Schltdl.) Dillenb. & Kadereit [syn. Minuartia elegans (Cham. & Schltdl.) Schischk], Sabulina rossii (R.Br.) Dillenb. & Kadereit [syn. Minuartia rossii (R.Br.) Graebn.], Sabulina rubella (Wahlenb.) Dillenb. & Kadereit [syn. Minuartia rubella (Wahlenb.) Hiern.]. Four Canadian Arctic species, Minuartia biflora (L.) Schinz & Thell., Minuartia arctica (Steven ex Ser.) Graebn., Minuartia obtusiloba (Rydb.) House, and Minuartia yukonensis Hultén, are part of "clade 6" in Dillenberger and Kadereit (2014), which they recognize as the genus Cherleria L., with some 19 species. Combinations for these species in Cherleria are not available; we assume they will be published in a revision of Cherleria that is noted to be in preparation ( Dillenberger and Kadereit 2014, see their Appendix S3). Cherleria is distinguished from Sabulina by sepals obtuse and oblong (versus acute and linear-lanceolate) ( Dillenberger and Kadereit 2014). Minuartia macrocarpa (Pursh) Ostenfeld (= Pseudocherleria macrocarpa (Pursh) Dillenb. & Kadereit) is part of "clade 3", which is recognized as the new genus Pseudocherleria Dillenb. & Kadereit, with ca. 12 species. Pseudocherleria has obtuse sepals, but differs in its long acute multicellular hairs ( Dillenberger and Kadereit 2014). Minuartia groenlandica (Retzius) Ostenfeld (= Mononeuria groenlandica (Retzius) Dillenb. & Kadereit) is part of "clade 5", recognized as the genus Mononeuria Rchb., characterized by an annual or biennial habit and emarginate petals (sometimes absent) twice as long as the sepals ( Dillenberger and Kadereit 2014). There are no species of Minuartia s.s. in the Canadian Arctic. Of the above species only Sabulina elegans , Sabulina rossii , Sabulina rubella , Sabulina stricta , and Minuartia biflora occur in the CAA.

Sabulina stricta may be distinguished from the closely related and largely sympatric Sabulina rossii - Sabulina elegans species complex by the presence of branched flowering stems bearing two or more flowers (versus always unbranched and 1-flowered in the latter). Recent molecular evidence suggests that Sabulina stricta may be part of this species complex and not easily separable from the genetically diverse species Sabulina elegans ( Saarela et al. 2013b, S. Leung and L.J. Gillespie, unpubl. data).

Specimens examined.

Canada. Nunavut: Kitikmeot Region, Victoria Island, rocky hills S of large unnamed lake ca. 18 km ENE of Johansen Bay airstrip, 68°38'43"N, 110°40'9"W, 50-80 m, 14 July 2008, Gillespie, Saarela, Consaul & Bull 7966 (ALA, CAN-592334, MT, O).