Brook Floater vs Coast Trillium

Alasmidonta varicosa compared with Trillium ovatum

Key Differences

Brook Floater is Vulnerable while Coast Trillium is Least Concern.

Taxonomic Classification

Rank	Brook Floater	Coast Trillium
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Mollusca (Mollusks)	Magnoliophyta (Flowering Plants)
Class	Bivalvia (Bivalvia)	Liliopsida (Monocots)
Order	Unionida (Unionida)	Liliales (Liliales)
Family	Unionidae	Melanthiaceae
Genus	Alasmidonta	Trillium
Species	Alasmidonta varicosa	Trillium ovatum

Conservation Status

Brook Floater

VU — Vulnerable

Coast Trillium

LC — Least Concern

Physical Characteristics

Attribute	Brook Floater	Coast Trillium
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Brook Floater

Habitat

Native to North America, inhabiting ecosystems characteristic of the region.

Range

Found in United States. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Coast Trillium

Habitat

Typically found in grasslands, wetlands, forests, and cultivated landscapes.

Range

Found in United States.

Brook Floater

The Brook Floater (Alasmidonta varicosa) is a species in the genus Alasmidonta. It is currently classified as Vulnerable on the IUCN Red List. Native to North America, inhabiting ecosystems characteristic of the region.

Coast Trillium

Coast trillium (Trillium ovatum) is a spring-flowering perennial herb in the family Melanthiaceae, native to moist, shaded forests of western North America from British Columbia and Alberta south through the Pacific states to central California and east to Montana and Idaho. It grows in mixed conifer and deciduous forest understories, redwood forest, riparian woodland, and coastal range foothills, typically in deep, humus-rich, well-drained soils. Like all trilliums, it produces a whorl of three broad leaves, a single three-petalled flower that opens white and turns pink to deep rose with age, and takes many years to reach flowering maturity from seed. Seeds are dispersed by ants (myrmecochory) attracted to the oil-rich elaiosome attached to each seed. Coast trillium is assessed as Least Concern by the IUCN, though it is a legally protected plant in some US states due to its slow reproductive rate making populations sensitive to disturbance. Illegal collection from the wild for horticulture remains a concern. It is one of the most beloved wildflowers of the Pacific Northwest and is widely cultivated in woodland gardens.