Petrophytum cinerascens

Classification System: APG IV

Superregnum: Eukaryota
Regnum: Plantae
Cladus: Angiosperms
Cladus: Eudicots
Cladus: Core eudicots
Cladus: Rosids
Cladus: Eurosids I
Ordoo: Rosales

Familia: Rosaceae
Subfamilia: Amygdaloideae
Tribus: Spiraeeae
Genus: Petrophytum
Species: Petrophytum cinerascens
Name

Petrophytum cinerascens (Piper) Rydb.
Synonyms

Petrophyton cinerascens (Piper) Rydb.

References

Plant Profil - USDA

Vernacular names
English: Chelan rockmat or halfshrub rockmat

Petrophytum cinerascens (orth. var. Petrophyton cinerascens) is a rare species of flowering plant in the rose family known by the common names halfshrub rockmat and Chelan rockmat.[1][2] It is endemic to the state of Washington in the United States, where it occurs in just a few locations along the Columbia River in Chelan and Douglas Counties.[1][3]
Description

Petrophytum cinerascens is a mat-forming perennial herb growing in cracks and crevices in riverside cliffs. The stems are up to 30 cm (1 ft) long, arising from the mat of leaves. The stems bear racemes 2 to 6 cm (0.79 to 2.4 in) long of white flowers with many stamens. Blooming occurs in June through September.[1]

Conservation

There are five occurrences of this plant all in a 27-kilometer stretch of cliffs along the Columbia River in central Washington. Two of the occurrences have about 1000 individuals each; the other three have fewer.[1]

The plant is threatened by quarrying of rock nearby. Other threats include highway maintenance, introduced species of plants such as cheat grass (Bromus tectorum), herbicides, rock climbing, motor vehicle emissions, and global warming.[1]
References

Petrophyton cinerascens. The Nature Conservancy.
Petrophytum cinerascens. Washington Burke Museum.
"Petrophytum cinerascens (Piper) Rydb". Plants of the World Online. Royal Botanical Gardens Kew. Retrieved 8 June 2019.