Panarctic Flora

140101b Juniperus communis subsp. nana (Willd.) Syme

• Syme in Sowerby, Engl. Bot., ed. 3B, 8: 275 (1868). - Juniperus nana Willd., Sp. Pl. 4, 2: 854 (1806). Described from Austria. - Juniperus communis var. nana (Willd.) Celak., Prodr. Fl. Böhmen 1: 17 (1867).
• Juniperus communis var. alpina Sm., Fl. Brit. 3: 1086 (1804) nom. illeg.. - Juniperus communis subsp. alpina (Sm.) Celak., Prodr. Fl. Böhmen 1: 17 (1867) nom. illeg..
• ?Juniperus sibirica Lodd. ex Burgsd., Anl. Erzieh. Holzart. 1: 163, 220 (1787). Described from Siberia.
• ?Juniperus communis var. saxatilis Pall., Fl. Ross. 1, 2: 12 (1788). Lectotype: Siberia. Pallas, Fl. Ross. 1, 2: fig. 54A. 1788 (Farjon 2005: 271). - ?Juniperus communis subsp. saxatilis (Pall.) A.E. Murray, Kalmia 12: 21 (1982).
• ?Juniperus communis var. montana Aiton, Hort. Kew. 3: 414 (1789). Described from the British Isles.

2n= 22 (2x). - Europe (N, C, W), Siberia (N, S), Far East (N), Greenland. - Numerous reports.

Geography: Amphi-Atlantic - European - Asian: ICE NOR RUS SIB RFE GRL.

Notes: The priority names of this taxon at ranks of subspecies and variety have been disputed. Christensen (1985, 2000) argued that the oldest name at rank of subspecies is subsp. alpina (Sm.) Celak. 1867. This name is, however, made illegitimate by its basionym - var. alpina Sm. 1804 - being predated by var. alpina Chaix 1786 based on a different type. The correct name for the subspecies therefore seems to be subsp. nana (Willd.) Syme 1868. Christensen (2000) entered the following names as synonyms: Juniperus sibirica Burgsd. 1787, J. communis var. saxatilis Pall. 1788 and J. communis var. montana Aiton 1789. The priority name at varietal rank may be var. saxatilis as suggested by Adams (2004); however, see Farjon (2005: 274): "The validation of Pallas' name remains somewhat problematic because strictly speaking the plate lacks diagnostic features (details) and the description is unclear".

Plants of the two boreal subspecies attain the general habit of subsp. nana in harsh sites: prostrate growth and shorter, broader and more incurved leaves. It is therefore difficult, in most regions, to delimit what probably are two (arctic-)alpine races from modifications of boreal plants. The range of subsp. nana may have been over-estimated in Eurasia, and this race may be absent from North America except for Greenland.

Russian authors have almost uniformly identified Burgsdorff's J. sibirica with subsp. nana. This conclusion remains to be checked both by morphology and by molecular markers. The Siberian plant is mainly a forest (boreal) plant and differs from the arctic-alpine European and Greenlandic plants in some features. Two collections (ALA) from the Seward Peninsula in western Alaska resemble the Siberian plants morphologically but should be confirmed by molecular means before acceptance of subsp. nana (in the European meaning) from North America.

Adams (1993) mapped var. montana (by Adams and Nguyen 2007 and Adams 2008 as var. saxatilis) with a disjunction between Greenland and the western American Cordillera. The Greenland plants correspond closely in morphology and molecular markers to the arctic-alpine European ones, i.e., subsp. nana. The Cordilleran plants differ morphologically, are misfits within subsp. nana, and may be a different subspecies that reaches the southern Yukon Territory and southern Alaska (by Adams 2004 first invalidly as var. carlottae, later by Adams 2008 as var. charlottensis R.P. Adams) but not the Arctic according to the material in ALA. The studies of Adams and collaborators do not seem to have included samples from its range.