The name of the genus to which the starflower belongs, Trientalis, is a Latin term meaning ‘one third of a foot’, referring to the height of the plant. The second part of the scientific name, borealis, means ‘northern’, relating to the plant’s geographic range. The starflower gained its common name from its star-shaped flowers (2) (4).
The starflower is a perennial herb (2) (4) (5). Towards the tip of the stems (3) (4) there are whorls of five to ten leaves (2) (6), which can all be different shapes and sizes, even on the same plant (5). On each plant, there are up to three (4) (5) white, star-shaped flowers (2) (4), which have five to seven petals (5) and five to nine stamens in the centre (2). The flowers grow above the whorl of leaves at the tip of the stem (2) (5).
The numerous tiny, black seeds are enclosed within a small, round capsule (6), which is divided into five segments (5).
- Also known as
- northern starflower, star-flower.
- Trientalis americana, Trientalis borealis subsp. borealis.
- Height: 8 - 29 cm (2)
- Stem length: 4 - 20 cm (3)
- Leaf length: 4 - 13 cm (2)
- Leaf width: 1 - 3 cm (2)
- Flower width: 1 - 1.5 cm (2)
The starflower reproduces both sexually and vegetatively. Sexual reproduction occurrs much less frequently (6) and is reliant on the plant being pollinated by bees during its flowering period (4), which generally runs between May and June (2). Before germinating, the seeds must undergo a period of cold temperatures, and do not begin to grow until autumn the year after they have been fertilised (4). Vegetative reproduction begins in spring when a new shoot begins to develop from the underground tubers. The rhizome grows and becomes enlarged throughout the summer and eventually a new tuber begins to grow, which produces premature leaves and roots. The new tuber is visible above ground the following spring (6).
From mid-summer onwards, the leaves of the starflower become yellow, eventually becoming loose and dropping to the ground. After it sheds its leaves, the starflower is visible above ground as a single stem with one or two seed capsules at its tip. The exact flowering period of the starflower is variable and depends on the geographic location of the individual (4).
The range of the starflower stretches across Canada, from British Columbia and the Yukon in the west to Newfoundland and Nova Scotia in the east, although it is absent from the Northwest Territories and Nunavut. It is also found in the United States along, the west coast from California to Washington, and the east coast from Georgia to Maine. Its distribution also spreads inland from the eastern coast to more central states such as Tennessee, Illinois and Minnesota (3) (7).
The shade-tolerant starflower (6) is found in deciduous (2) (4), coniferous (2) (3) (4) (6) and boreal forests (6). It has a preference for damp areas and is regularly found in riparian habitats (2), while its preference for soil is less specific. Populations have been found in dry, sandy and acidic soils (4). This species inhabits areas at elevations between 30 and 1,000 metres (3).
The starflower has not yet been assessed by the IUCN.
There are not currently known to be any threats to the starflower.
There are not currently known to be any specific conservation measures in place for the starflower, although this species is listed as endangered in Georgia (5).
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- Boreal forest
- The sub-Arctic forest of the high northern latitudes that surrounds the North Pole and is mainly composed of coniferous trees.
- Deciduous forest
- Forest consisting mainly of deciduous trees, which shed their leaves at the end of the growing season.
- The fusion of gametes (male and female reproductive cells) to produce an embryo, which grows into a new individual.
- A category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.
- To begin to grow, usually following a period of dormancy and in response to favourable conditions. For example, the sprouting of a seedling from a seed.
- A small, non-woody, seed bearing plant in which all the aerial parts die back at the end of each growing season.
- A plant that normally lives for more than two years. After an initial period, the plant usually produces flowers once a year.
- To transfer pollen grains from the stamen (male part of a flower) to the stigma (female part of a flower) of a flowering plant. This usually leads to fertilisation, the development of seeds and, eventually, a new plant.
- An underground, horizontal plant stem that produces roots and shoots.
- Relating to the banks of rivers and streams.
- The male reproductive organ of a flower. Each stamen is comprised of an anther (the pollen-producing organ) and a filament (stalk).
- In plants, a thickened stem or root that acts as an underground storage organ. Roots and shoots grow from growth buds, called ‘eyes’, on the surface of the tuber.
- Vegetative reproduction
- Type of asexual reproduction (reproduction that does not involve the formation of sex cells) in which a new plant grows from part of another plant, rather than from seeds or spores. The resulting individual is genetically identical to the original plant.
- In animals, a spiral or coil in the shell of a snail. In plants, a set of leaves, flowers, or branches that spring from a stem at the same point and encircle it.
Integrated Taxonomic Information System (ITIS) (January, 2014)
Grob, B.L. (2007) Kasey Hartz Natural Area Reference Sheet: Trientalis borealis. Muskegon Community College, Michigan. Available at:
Flora of North America - Trientalis borealis (January, 2014)
US Forest Service (January, 2014)
Chafin, L.G. (2007) Field Guide to the Rare Plants of Georgia. University of Georgia Press, Athens, Georgia.
North Michigan University Biology Department (2011) Formal Report: Summary of Scientific Research Concerning Trientalis borealis. Northern Michigan University, Marquette, Michigan. Available at:
United States Department of Agriculture - Starflower (January, 2014)