Variation in Linnaea borealis (Linnaeaceae) across North America and Greenland

  • Peter F. Zika WTU Herbarium, University of Washington
  • Gordon C. Tucker EIU Herbarium, Dept. of Biological Sciences, Eastern Illinois University


Three subspecies of Linnaea borealis (Linnaeaceae) are reported from North America. We reviewed the literature and herbarium specimens, and were able to consistently recognize two taxa in the herbarium and in nature. Floral characters distinguish the two subspecies. Linnaea borealis subsp. borealis is widespread across Eurasia, and is common in the Aleutian Islands and mainland Alaska. Linnaea borealis subsp. longiflora is represented in eastern and southeastern Alaska, south to California, and east to the Atlantic and Greenland, and includes plants called subsp. americana. PCA and statistical analyses support the recognition of two infraspecific taxa. Lectotypes are designated for Linnaea borealis var. longiflora and Linnaea borealis var. longiflora forma orientalis. Also, a neotype is chosen for Linnaea americana.


Abrams, L. & R.S. Ferris. 1960. Illustrated flora of the Pacific states Washington, Oregon and California: Volume IV, Bignoniaceae to Compositae, bignonias to sunflowers. Stanford University Press, Stanford, U.S.A.
Ackerfield, J. 2015. Flora of Colorado. Bot. Misc. 41. Botanical Research Institute of Texas Press, Fort Worth, U.S.A.
Backlund, A. & N. Pyck. 1998. Diervilliaceae and Linnaeaceae, two new families of caprifolioids. Taxon 47:657–661.
Barrett, S.C.H. & K. Helenurm. 1987. The reproductive biology of boreal forest herbs I: breeding systems and pollination. Canad. J. Bot. 65:2036–2046.
Brenner, M. 1908. Några Linnaea-former i Finland. Ingå. Meddeland. Soc. Fauna Fl. Fenn. 34:89–97.
Brenner, M. 1910. Nya Linnaea-former från Ingå. Meddeland. Soc. Fauna Fl. Fenn. 36:9–13.
Christenhusz, M.J.M. 2013. Twins are not alone: a recircumscription of Linnaea (Caprifoliaceae). Phytotaxa 125:25–32.
Cooperrider, T.S. 1995. The Dicotyledoneae of Ohio. Part 2. Linaceae through Campanulaceae. Ohio State University Press, Columbus, Ohio, U.S.A.
Cronquist, A. 1959. Linnaea L. Twinflower. In: C.L. Hitchcock, A. Cronquist, & M. Ownbey. Vascular plants of the Pacific Northwest. Part 4: Ericaceae through Campanulaceae. University of Washington Press, Seattle, Washington, U.S.A. Pp. 455–456.
Cronquist, A. & A.H. Holmgren. 1984. Caprifoliaceae. In: A. Cronquist, A.H. Holmgren, N.H. Holmgren, J.L. Reveal & P.K. Holmgren. 1984. Intermountain flora. Vascular plants of the intermountain west, U.S.A. Vol. 4, Subclass Asteridae (except Asteraceae). The New York Botanical Garden, Bronx, New York, U.S.A. Pp. 538–544.
Donoghue, M.J., T. Eriksson, P.A. Reeves, & R.G. Olmstead. 2001. Phylogeny and phylogenetic taxonomy of Dipsacales, with special reference to Sinadoxa and Tetradoxa (Adoxaceae). Harvard Pap. Bot. 6:459–479.
Douglas, G.W., G.B. Straley, D. Meidinger, & J. Pojar, eds. 1998. Illustrated flora of British Columbia, Vol. 2. Dicotyledons (Balsaminaceae through Cuscutaceae). British Columbia Ministry of Environment, Lands and Parks, Ministry of Forests, Victoria, British Columbia, Canada.
Durand, E. 1869. Appendix M. Plants collected by the United States Coast Survey on the geographical reconnaissance of Alaska, under the direction of George Davidson, assistant United States Coast Survey. Collection by Albert Kellogg, M. D., aid United States Coast Survey; nomenclature by Elias Durand, esq., Academy of Natural Sciences, Philadelphia. In: B. Peirce, ed. Report of the Superintendent of the United States Coast Survey, showing the progress of the survey during the year 1867. Government Printing Office, Washington, D.C., U.S.A. Pp. 322–324.
Elven, R. 2011. Linnaea L. In: R. Elven, D.F. Murray, V.Y. Razzhivin, & B.A. Yurtsev, eds. Annotated checklist of the panarctic flora (PAF) vascular plants. Available at Accessed February 2017.
Fernald, M.L. 1922. The American variations of Linnaea borealis. Rhodora 24:210–212.
Fernald, M.L. 1950. Gray's manual of botany, 8th ed. D. Van Nostrand Co., New York, U.S.A.
Forbes, J. 1833. Hortus woburnensis, a descriptive catalogue of upwards of six thousand ornamental plants cultivated at Woburn Abbey. With numerous illustrative plans for the erection of forcing houses, green houses, &c. and an account of their management throughout the year. James Ridgeway, London, U.K.
Gilman, A.V. 2015. New flora of Vermont. Mem. New York Bot. Gard. 110:1–614.
Gleason, H.A. & A. Cronquist. 1991. Manual of vascular plants of northeastern United States and adjacent Canada, 2nd ed. The New York Botanical Garden, Bronx, New York, U.S.A.
Granstrom, A. 1982. Seed banks in five boreal forest stands originating between 1810 and 1963. Canad. Jour. Bot. 60:1815–1821.
Haines, A. 2011. New England Wildflower Society's Flora Novae Angliae; A manual for the identification of native and naturalized higher vascular plants of New England. New England Wildflower Society and Yale University Press, New Haven, Connecticut, U.S.A.
Halverson, N.M. 1986. Major indicator shrubs and herbs on National Forests of western Oregon and southwestern Washington. R6-TM-229. U.S. Department of Agriculture, Forest Service, Pacific Northwest Region, Portland, Oregon, U.S.A.
Harrington, H.D. 1954. Manual of the plants of Colorado, for identification of the ferns and flowering plants of the state. Sage Books, The Swallow Press, Chicago, Illinois, U.S.A.
Harris, S.K., J.H. Langenheim, F.L. Steele, & M. Underhill. 1964. Mountain flowers of New England. Appalachian Mountain Club, Boston, Massachusetts, U.S.A.
Howell, T. 1900. A flora of northwest America: containing brief descriptions of all the known indigenous and naturalized plants growing without cultivation north of California, west of Utah and south of British Columbia. Volume 1, Phanerogamae. Published by the author, Portland, Oregon, U.S.A. [Fascicle 3] Pp. 275–386.
Hultén, E. 1930. Flora of Kamtchatka and the adjacent islands. IV. Dicotyledonae, Pyrolaceae - Compositae. Kungl. Svenska Vetenskapsakad. Handl. 8(2):1–358, with 6 pl.
Hultén, E. 1937. Flora of the Aleutian Islands and westernmost Alaska Peninsula with notes on the flora of Commander Islands. Bokf?rlags Aktiebolaget Thule, Stockholm, Sweden.
Hultén, E. 1949. Flora of Alaska and Yukon. IX. Dicotyledoneae Tubiflorae 2 (Boraginaceae, Labiatae, Solanaceae, Scrophulariaceae, Orobanchaceae, Lentibulariaceae), Plantaginales, Rubiales, Campanulatae 1 (Campanulaceae). Part 9:1345–1481.
Hultén, E. 1968. Flora of Alaska and neighboring territories. Stanford University Press, Palo Alto, California, U.S.A.
Jacobs, B., N. Pyck, & E. Smets. 2010. Phylogeny of the Linnaea clade: Are Abelia and Zabelia closely related? Molec. Phylogen. Evol. 57:741–752.
Jarvis, C. 2007. Order out of chaos. The Linnean Society of London in association with the Natural History Museum, London, U.K.
Jonsell, B. 1993. Linnaea borealis. In: C.E. Jarvis, F.R. Barrie, D.M. Allan & J.L. Reveal, eds. A list of Linnaean generic names and their types. Regnum Veg. 127:61.
Landrein, S. & G. Prenner. 2016. Structure, ultrastructure and evolution of floral nectaries in the twinflower tribe Linnaeeae and related taxa (Caprifoliaceae). Bot. J. Linn. Soc. 181:37–69.
McNeill, J., F.R. Barrie, W.R. Buck, V. Demoulin, W. Greuter, D. Hawksworth, P.S. Herendeen, S. Knapp, K. Marhold, J. Prado, W.F.P.-H. van Reine, G.F. Smith, J.H. Wiersema, & N.J. Turland. 2012. International code of nomenclature for algae, fungi and plants (Melbourne Code). Regnum Veg. 154:1–240. Accessed Nov 2016.
Moss, E.H. & J.G. Packer. 1983. Flora of Alberta: A manual of flowering plants, conifers, ferns and fern allies found growing without cultivation in the province of Alberta, Canada, 2nd ed., revised by J.G. Packer. University of Toronto Press, Toronto, Canada.
Piper, C.V. 1906. Flora of the state of Washington. Contr. U.S. Natl. Herb. 11:1–637.
Piper, C.V. & R.K. Beattie. 1915. Flora of southeastern Washington and adjacent Idaho. The New Era Printing Company, Lancaster, Pennsylvania, U.S.A.
Pojarkova, A.I. 2000. Genus 1400. Linnaea Gronov. ex L. In: B.K. Schischkin, ed. Flora of the USSR, Volume XXIII Bignoniaceae–Valerianaceae. [Translated from Russian] Smithsonian Institution Libraries, Washington, D.C., U.S.A. Pp. 443–446.
R Core Team. 2016. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria.
Rydberg, P.A. 1907. Linnaeus and American botany. J. New York Bot. Gard. 8:123–135.
Rydberg, P.A. 1917. Flora of the Rocky Mountains and adjacent plains, Colorado, Utah, Wyoming, Idaho, Montana, Saskatchewan, Alberta, and neighboring parts of Nebraska, South Dakota, North Dakota, and British Columbia. Published by the author, New York, U.S.A.
Scobie, A.R. & C.C. Wilcock. 2009. Limited mate availability decreases reproductive success of fragmented populations of Linnaea borealis, a rare, clonal self-incompatible plant. Ann. Bot. 103:835–846.
Shear, C.L. & N.E. Stevens. 1921. The correspondence of Schweinitz and Torrey. Mem. Torrey Bot. Club 3:119–300.
Stafleu, F.A. & R.S. Cowan. 1976. Taxonomic literature. A selective guide to botanical publications and collections with dates, commentaries and types. Volume 1: A–G, 2nd ed. Bohn, Scheltema & Holkema, Utrecht, The Netherlands. Accessed Nov 2016.
Torrey, J. 1822. Notice of the plants collected by Professor D.B. Douglass, of West Point, in the expedition under Governour Cass, during the summer of 1820, around the Great Lakes and the upper waters of the Mississippi. Amer. J. Sci. 4:56–68.
Torrey, J. 1874. Phanerogamia of Pacific North America. In: A. Gray, ed. United States Exploring Expedition, during the years 1838, 1839, 1840, 1841, 1842, under the command of Charles Wilkes, U. S. N., vol. 17, botany. Sherman & Co., Philadelphia, Pennsylvania, U.S.A. Pp. 205–514.
Torrey, J. & A. Gray. 1838–1841. A flora of North America: Containing abridged descriptions of all the known indigenous and naturalized plants growing north of Mexico; arranged according to the natural system, 2 vols. Wiley & Putnam, New York, U.S.A.
Wickham, H. 2009. ggplot2: Elegant graphics for data analysis. Springer-Verlag, New York, U.S.A.
Wilkes, C. 1844. Narrative of the United States Exploring Expedition during the years 1838, 1839, 1840, 1841, 1842, in five volumes and an atlas. Vol. 4. C. Sherman, Philadelphia, Pennsylvania, U.S.A. Accessed Nov 2016.
Wittrock, V.B. 1907. Linnaea borealis L. species polymorpha et polychroma. Acta Horti Berg. 4:1–187.
Zhang, A.-Q., Y.-Z. Xiong, & S.-Q. Huang. 2014. Maintenance of self-incompatibility in peripheral populations of a circumboreal woodland subshrub. AoB Pl. 6: plu063. Available on-line at: Accessed February 2017.
How to Cite
Zika, P. F., & Tucker, G. C. (2017). Variation in Linnaea borealis (Linnaeaceae) across North America and Greenland. Journal of the Botanical Research Institute of Texas, 11(1), 67-79.