Brook Floater vs Common Script Lichen

Alasmidonta varicosa compared with Graphis scripta

Key Differences

Brook Floater is Vulnerable while Common Script Lichen is Least Concern.

Taxonomic Classification

Rank	Brook Floater	Common Script Lichen
Kingdom	Animalia (Animals)	Fungi (Fungi)
Phylum	Mollusca (Mollusks)	Ascomycota (Sac Fungi)
Class	Bivalvia (Bivalvia)	Lecanoromycetes (Lecanoromycetes)
Order	Unionida (Unionida)	Ostropales (Ostropales)
Family	Unionidae	Graphidaceae
Genus	Alasmidonta	Graphis
Species	Alasmidonta varicosa	Graphis scripta

Conservation Status

Brook Floater

VU — Vulnerable

Common Script Lichen

LC — Least Concern

Physical Characteristics

Attribute	Brook Floater	Common Script Lichen
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.

Common Script Lichen

Habitat

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

Range

Widely distributed across Asia (Taiwan), Europe (4 countries), North America (United States), and South America (Colombia).

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.

Common Script Lichen

<em>Graphis scripta</em>, the common script lichen, is a crustose lichen in the family Graphidaceae, order Graphidales, with a cosmopolitan distribution spanning Asia, Europe, North America, and South America. This species grows as a flat, tightly attached crust on the smooth bark of deciduous trees in humid, shaded woodland habitats, where it is often among the most frequently encountered bark lichens. The distinctive feature of <em>Graphis scripta</em> is its elongated, script-like apothecia — black, slit-like fruiting bodies that resemble ancient writing and give the species its common name. As a lichen, it represents a stable mutualistic association between a fungal partner (mycobiont) and photosynthetic algal or cyanobacterial partners (photobionts). The species is listed as Least Concern by the IUCN, reflecting its wide distribution and tolerance across a range of forested habitats. It is considered sensitive to air pollution, particularly sulfur dioxide, making it a useful bioindicator of air quality. Biological traits for this species remain poorly documented in the scientific literature, including data on growth rates, lifespan, and detailed ecological interactions beyond its known substrate preferences.