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Trientalis borealis Raf.
Starflower
Federal Protection: No US federal protection
State Protection: Endangered
Global Rank: G5
State Rank: S1S2
Element Locations Tracked in Biotics: Yes
SWAP 2015 Species of Greatest Conservation Need (SGCN): No
SWAP 2025 Species of Greatest Conservation Need (SGCN): Yes
2025 SGCN Priority Tier: Moderate Conservation Concern
Element Occurrences (EOs) in Georgia: 10
Habitat Summary for element in Georgia: Rocky, northern hardwood forests
Perennial herb with smooth, green, erect stems 1 - 10 inches (3 - 25 cm) tall, usually around 6 inches (15 cm), with small, alternate bracts at mid-stem and 4 - 7 lance-shaped leaves that are 1 - 4 inches (3 - 11 cm) long, arranged in a whorl at the top of the stem; leaves may be different sizes and shapes within a population and even on a single plant. Flowers are up to 0.6 inch (1.4 cm) wide, 1 - 3 per plant, with 5 - 9 white (rarely pink), pointed, spreading, petal-like lobes, held on slender stalks up to 0.8 - 2 inches (2 - 5 cm) long. Fruits are about 0.25 inch (6 - 8 mm) wide, round, with 5 segments opening to release many tiny, round seeds.
Young plants of Indian Cucumber-root (Medeola virginiana) have a single whorl of leaves at the top of the stem; their wiry stems are covered with cobwebby hairs.
Large Whorled Pogonia Orchid (Isotria verticillata) has whorled leaves but its stem is purplish to brownish-green. Small Whorled Pogonia (Isotria medeoloides) also has whorled leaves but its stem is grayish-green and waxy.
None in Georgia.
Moist, deciduous northern hardwood forests and boulderfields on high-elevation, north-facing slopes.
Starflower is a perennial herb that reproduces primarily by vegetative means. In early summer, rhizomes emerge from a tuber at the base of the plant. Over the course of the summer the rhizomes spread as much as 3 feet (1 meter) from the parent plant and develop starch-filled tubers at their tips, each tuber bearing root and shoot buds. The parent plant and the connecting rhizomes wither and die by late fall leaving behind several new – though genetically identical – plants in a patch up to 3 feet wide. To a lesser extent, Starflower also reproduces sexually. Its flowers have several features that discourage self-pollination, and it will set fruit only after cross-pollination. The flowers are pollinated by bees which must transport pollen between flowers of genetically different patches in order to effect cross-pollination. The lack of successful cross-pollination due to the long distances between genetically dissimilar plants may account for the low rate of sexual reproduction.
Surveys are best conducted during flowering and fruiting (May–June).
Georgia, Tennessee, North Carolina, and north into Canada.
Logging, clearing, and road-building. Climate change is likely to raise temperatures in Georgia's Blue Ridge mountains which may prove fatal to this northern species.
| Threat 1 | Threat 2 | Threat 3 | |
|---|---|---|---|
| General Threat | Climate change & severe weather | None | None |
| Specific Threat | None | None | None |
Trientalis borealis is ranked S1S2 by the Georgia Department of Natural Resources, indicating that the species is imperiled in Georgia. It is listed as Endangered by the State of Georgia. Ten populations have been documented in Georgia, all in the Chattahoochee National Forest; most have been confirmed since 2000.
Avoid logging, clearing, road-building, and other mechanical disturbances in rich hardwood forests and boulderfields.
Georgia’s plants are the southernmost populations of this species. Plants occurring at the periphery of a species’ range are thought to be of special conservation importance. Peripheral populations are usually smaller and less genetically diverse within the population, but genetically divergent from centrally located populations. These genetic differences may confer special survival traits that plants in other portions of the species’ range lack, such as the ability to survive changes in the climate or the arrival of a new pathogen. Peripheral populations may be in the process of evolving into a new species. They are especially deserving of conservation action.
Anderson, R.C. and M.H. Beare. 1983. Breeding system and pollination ecology of Trientalis borealis (Primulaceae). American Journal of Botany 70(3): 408-415. https://bsapubs.onlinelibrary.wiley.com/doi/abs/10.1002/j.1537-2197.1983.tb06408.x
Anderson R.C. and O.L. Loucks. 1973. Aspects of the biology of Trientalis borealis Raf. Ecology 54: 798-808. https://esajournals.onlinelibrary.wiley.com/doi/abs/10.2307/1935674
Chafin, L.G. 2007. Field guide to the rare plants of Georgia. State Botanical Garden of Georgia and University of Georgia Press, Athens.
Cholewa, A.F. 2009. Trientalis borealis species account. Flora of North America, vol. 8. Oxford University Press, New York. http://beta.floranorthamerica.org/Trientalis_borealis
Duncan, W.H. 1970. The southern limits of Trientalis borealis. Rhodora 72: 489-492. https://www.jstor.org/stable/23311536?seq=1#metadata_info_tab_contents
GADNR. 2020. Element occurrence records for Trientalis borealis. Georgia Department of Natural Resources, Wildlife Resources Division, Social Circle, Georgia.
NatureServe. 2020. Trientalis borealis species account. NatureServe Explorer. NatureServe, Arlington, Virginia. https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.141286/Trientalis_borealis
Patrick, T.S., J.R. Allison, and G.A. Krakow. 1995. Protected plants of Georgia. Georgia Department of Natural Resources, Natural Heritage Program, Social Circle.
Weakley, A.S. 2015. Flora of the southern and mid-Atlantic States. University of North Carolina Herbarium, University of North Carolina, Chapel Hill. http://www.herbarium.unc.edu/flora.htm
Linda G. Chafin
L. Chafin, Jan. 2009: original account
K. Owers, Feb. 2010: added pictures
L. Chafin, June 2020: updated original account.
