''Tiarella austrina'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Saxifragaceae Saxifragaceae is a family of herbaceous perennial flowering plants, within the core eudicot order Saxifragales. The taxonomy of the family has been greatly revised and the scope much reduced in the era of molecular phylogenetic analysis. The fa ...

. The specific name ''austrina'' means "from the south". Being

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to the

southeastern United States The Southeastern United States, also referred to as the American Southeast or simply the Southeast, is a geographical region of the United States. It is located broadly on the eastern portion of the southern United States and the southern por ...

, it is sometimes referred to as the southern foamflower. It is one of two species of ''Tiarella'' that spread by stolons (the other being ''

Tiarella stolonifera ''Tiarella stolonifera'' is a species of flowering plant in the family Saxifragaceae. The specific name ''stolonifera'' means "spreading by stolons", an important characteristic of this species (not to be confused with '' Tiarella austrina'', whi ...

'').

Description

''Tiarella austrina'' is a

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wid ...

herbaceous plant Herbaceous plants are vascular plants that have no persistent wood, woody stems above ground. This broad category of plants includes many perennial plant, perennials, and nearly all Annual plant, annuals and Biennial plant, biennials. Definition ...

with a short, slender rhizome. It has a leafy flowering stem and relatively large basal leaves with an extended terminal lobe. Most importantly, the species has the ability to produce stolons.

Identification

To positively identify ''Tiarella austrina'', all of the following key features must be verified (in any order): * Stolon present * Basal leaves usually longer than wide * Basal leaf lobes usually acute-acuminate with the terminal lobe prominently extended * Flowering stem usually with 1–2 leaves or foliaceous bracts The key features listed above are similar to those of ''

Tiarella nautila ''Tiarella nautila'' is a species of flowering plant in the family Saxifragaceae. The specific name ''nautila'' alludes to its sail-like stem leaves. Accordingly, it is sometimes called the sail-leaf foamflower. The species is narrowly endemic to ...

'' but the presence of the stolon rules out that species.

Taxonomy

In 1937, Olga Lakela described ''Tiarella cordifolia'' var. ''austrina'', a variety of ''T. cordifolia'' with stolons. Guy Nesom raised this variety to species rank in 2021. Consequently, ''Tiarella cordifolia'' var. ''austrina'' is a basionym for ''Tiarella austrina'' .

Distribution

In eastern North America, ''Tiarella austrina'' is narrowly endemic to the southeastern United States where it occurs mainly in the southern

Blue Ridge Mountains The Blue Ridge Mountains are a Physiographic regions of the world, physiographic province of the larger Appalachian Mountains range. The mountain range is located in the Eastern United States, and extends 550 miles southwest from southern Pennsy ...

of southwestern North Carolina, southeastern Tennessee, northeastern Georgia, and northwestern South Carolina. Counties where the species is known to occur include: * ''Alabama'': Jackson, Madison * ''Georgia'': Dawson, Habersham, Rabun, Stephens, Towns, White * ''North Carolina'': Buncombe, Cherokee, Clay, Graham, Haywood, Henderson, Jackson, Macon, Polk, Swain, Transylvania * ''South Carolina'': Greenville, Oconee, Pickens * ''Tennessee'': Blount, Cocke, Franklin, Monroe, Sevier The ranges of ''Tiarella austrina'' and ''

'' overlap in Georgia (Dawson, Towns, White), North Carolina (Cherokee), and Tennessee (Monroe). Both ''Tiarella austrina'' and ''

'' occur in Buncombe County, North Carolina. A small disjunct population of ''T. austrina'' overlaps ''

Tiarella wherryi ''Tiarella wherryi'' is a species of flowering plant in the family Saxifragaceae. The specific name ''wherryi'' recognizes Edgar Wherry, the botanist who collected some of the first specimens in the early 1930s. Commonly called Wherry's foamflow ...

'' in northeastern Alabama (Jackson, Madison) and adjacent south-central Tennessee (Franklin).

Conservation

The global conservation status of ''Tiarella austrina'' is unknown. It is uncommon (S3) in North Carolina.

References

Bibliography

* * * {{Taxonbar, from=Q114836636 austrina Flora of the United States Flora of the Southeastern United States Flora of the Appalachian Mountains Plants described in 1937 Taxa named by Guy L. Nesom Flora without expected TNC conservation status