Brook Floater vs Clint Crisp-Moss

Alasmidonta varicosa compared with Tortella densa

Key Differences

Brook Floater is Vulnerable while Clint Crisp-Moss is Least Concern.

Taxonomic Classification

Rank	Brook Floater	Clint Crisp-Moss
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Mollusca (Mollusks)	Bryophyta
Class	Bivalvia (Bivalvia)	Bryopsida (Bryopsida)
Order	Unionida (Unionida)	Pottiales (Pottiales)
Family	Unionidae	Pottiaceae
Genus	Alasmidonta	Tortella
Species	Alasmidonta varicosa	Tortella densa

Conservation Status

Brook Floater

VU — Vulnerable

Clint Crisp-Moss

LC — Least Concern

Physical Characteristics

Attribute	Brook Floater	Clint Crisp-Moss
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.

Clint Crisp-Moss

Habitat

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

Range

Distributed across Norway, Sweden, and 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.

Clint Crisp-Moss

Clint Crisp-moss, Tortella densa, is a small acrocarpous moss in the family Pottiaceae found on exposed limestone pavement, cliff ledges, and calcareous rock outcrops in temperate Europe, with strongholds in the Yorkshire Dales, the Burren of Ireland, and similar karst landscapes. The common name 'clint' refers to the raised limestone blocks of limestone pavement habitats, and 'crisp-moss' describes the crinkled, crisped appearance of the dry leaf margins. When moistened, the leaves uncurl and spread, revealing the characteristic nerve extending to the leaf tip. Tortella densa forms dense, cushion-like or turf-forming colonies on exposed limestone surfaces and in sheltered grykes (the fissures between clints), tolerating periodic desiccation and temperature extremes. Limestone pavement is a rare and highly specialized habitat that supports a distinctive community of plants, mosses, liverworts, and invertebrates, and is legally protected in the United Kingdom and Ireland as a priority habitat under European conservation law. The loss of limestone pavement to quarrying, the covering of surfaces by soil and vegetation succession, and the removal of clint-surface plants by collectors have threatened specialist bryophytes of this habitat. Clint Crisp-moss is considered of conservation concern in Britain and Ireland.