''Tiarella austrina'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Saxifragaceae Saxifragaceae is a family of Herbaceous plant, herbaceous Perennial plant, perennial flowering plants, within the core eudicot Order (biology), order Saxifragales. The Taxonomy (biology), taxonomy of the family has been greatly revised and the ...

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

endemic Endemism is the state of a species being found only 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 foun ...

to the

southeastern United States The Southeastern United States, also known as the American Southeast or simply the Southeast, is a geographical List of regions in the United States, region of the United States located in the eastern portion of the Southern United States and t ...

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

stolon In biology, a stolon ( from Latin ''wikt:stolo, stolō'', genitive ''stolōnis'' – "branch"), also known as a runner, is a horizontal connection between parts of an organism. It may be part of the organism, or of its skeleton. Typically, animal ...

s (the other being '' Tiarella stolonifera'').

Description

''Tiarella austrina'' is a

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

herbaceous plant Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition o ...

with a short, slender

rhizome In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and Shoot (botany), shoots from its Node (botany), nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from ...

. It has a leafy flowering stem and relatively large

basal leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, fl ...

with an extended terminal lobe. Most importantly, the species has the ability to produce

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'', the foamflowers, is a genus of flowering plants in the family Saxifragaceae. The generic name ''Tiarella'' means "little turban", which suggests the shape of the seed capsules. Worldwide there are seven species, one each in eastern ...

'' 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

s. Guy Nesom raised this variety to species rank in 2021. Consequently, ''Tiarella cordifolia'' var. ''austrina'' is a

basionym In the scientific name of organisms, basionym or basyonym means the original name on which a new name is based; the author citation of the new name should include the authors of the basionym in parentheses. The term "basionym" is used in both botan ...

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 United States, physiographic province of the larger Appalachian Highlands range. The mountain range is located in the Eastern United States and extends 550 miles southwest from southern ...

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 '' Tiarella stolonifera'' 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 epithet ''wherryi'' recognizes Edgar Wherry, the botanist who collected some of the first specimens in the early 1930s. Commonly called Wherry's foamf ...

'' 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