Linnaea borealis

twinflower

Caprifoliaceae

The Basics

Taxonomy: Kingdom - Plantae (plants). Subkingdom - Tracheobionta (vascular plants). Superdivision - Spermatophyta (seed plants). Division - Magnoliophyta (flowering plants). Class - Magnoliopsida (dicotyledons). Subclass - Asteridae. Order - Dipsacales. Family - Caprifoliaceae (honeysuckle). Genus - Linnaea L. (twinflower). Species - Linnaea borealis L. (twinflower).

Ecology: Twinflower is a native, evergreen, dwarf shrub. It is creeping or trailing in growth form, with numerous short aerial stems rising from the stolon. With time, stolons may become shallowly buried beneath litter and duff layers; maximum depth of twinflower stolons in a mixed conifer old-growth forest of central Oregon was 0.27 cm below the soil surface. Aerial stems become woody with age but rarely exceed 0.30 cm in diameter. The root crown of these stems is positioned at or just beneath the duff or soil surface. Twinflower has a shallow, fibrous network of roots with their growing points within and slightly below the duff layer. Twinflower is found in recently disturbed, seral, and climax plant communities. Twinflower tolerates a wide spectrum of light intensity. It grows in full daylight in alpine meadows and peat bogs, but subcanopy light has been measured at 2 percent of full daylight in a closed-canopy mountain hemlock-western redcedar.

Identification

This is a creeping ground cover with trailing stems reaching 3 ft. in length. These groups of slender, woody stems bear glossy, bright, evergreen leaves arranged in pairs. The delicately fragrant flowers are pinkish, bell-shaped and in nodding pairs at the end of 4-6 in. stalks.A low, delicate, matted evergreen plant with trailing stems having short, upright branches, each terminated by 2 pinkish-white, nodding bell-shaped flowers. Stems hairy.

Threats

Twinflower is a fire avoider. During fire, small patches of twinflower in draws, moist duff, or other protected places usually escape burning...Twinflower is killed even by low-intensity fire...Twinflower sometimes colonizes new areas after fire...Twinflower most commonly establishes in burn areas from stolons produced by these unburned plants. It also establishes from animal-dispersed seed.

Reproduction

Vegetative reproduction by stolons is the primary method of twinflower regeneration. Twinflower first produces stolons at 5 to 10 years of age. Sexual reproduction is uncommon, but seedlings are occasionally found in burned or other disturbed areas. Pollination is effected by native bees and syrphid wasps; rarely, plants are self-fertile. Twinflower produces abundant seed, which apparently does not persist in seed banks.

Species Distribution

Citation

USDA Plant Database
USDA, NRCS. 2016. The PLANTS Database http://plants.usda.gov, 4 February 2016). National Plant Data Team, Greensboro, NC 27401-4901 USA.

Flora of North America
Flora of North America Editorial Committee, eds.  1993+.  Flora of North America North of Mexico.  19+ vols.  New York and Oxford.

Intermountain Herbarium
Consortium of Intermountain Herbaria. 2016. http//: intermountainbiota.org/portal/index.php. Accessed on February 04.

Burke Museum Plant Image Collection
The plant image collection at the Burke Museum, University of Washington.

Jepson Manual
The Jepson Manual: Vascular Plants of California. B.G. Baldwin, D.H. Goldman, D.J. Keil, R. Patterson, T.J. Rosatti, and D.H. Wilken [editors]. 2012. 2nd edition, thoroughly revised and expanded. University of California Press, Berkeley, CA. $131.95, hardcover; 1600 pages. ISBN-13: 978-0520253124.