Foamflowers in Georgia
In November 2022, iNaturalist split Tiarella cordifolia into five species, all but one of which occur in Georgia: Tiarella nautila, Tiarella wherryi, Tiarella cordifolia sensu stricto, and Tiarella austrina. These species are primarily distributed across northern Georgia.
Distribution of Tiarella in Georgia counties (overlap in bold):
- Tiarella nautila: Bartow, Cherokee, Cobb, Dawson, DeKalb, Fannin, Floyd, Forsyth, Gilmer, Hall, Jackson, Lumpkin, Murray, Pickens, Towns, Union, White
- Tiarella wherryi: Bartow, Carroll, Catoosa, Clay, Clayton, Dade, Decatur, Early, Floyd, Fulton, Gordon, Haralson, Harris, Polk, Quitman, Randolph, Upson, Walker, Whitfield
- Tiarella cordifolia sensu stricto: Clarke, Elbert, Jackson
- Tiarella austrina: Dawson, Habersham, Rabun, Stephens, Towns, White
Observations of Tiarella nautila in Georgia:
- Observations of Tiarella nautila in an expected county in Georgia
- Observations of Tiarella nautila in an unexpected county in Georgia
Observations of Tiarella wherryi in Georgia:
- Observations of Tiarella wherryi in an expected county in Georgia
- Observations of Tiarella wherryi in an unexpected county in Georgia
Observations of Tiarella cordifolia sensu stricto in Georgia:
- Observations of Tiarella cordifolia in an expected county in Georgia
- Observations of Tiarella cordifolia in an unexpected county in Georgia
Observations of Tiarella austrina in Georgia:
- Observations of Tiarella austrina in an expected county in Georgia
- Observations of Tiarella austrina in an unexpected county in Georgia
Tips for identification of Tiarella species:
- Identification of Tiarella austrina
- Identification of Tiarella cordifolia sensu stricto
- Identification of Tiarella nautila
- Identification of Tiarella wherryi
To distinguish species, look for stem leaves. Only Tiarella nautila and Tiarella austrina have stem leaves. Unlike Tiarella austrina, the flowering stems.of Tiarella nautila are consistently leafy. Although it's difficult to discern in photographs, the stem leaves of Tiarella nautila are larger than those of Tiarella austrina.
For details, including a color-coded range map and an identification key, see: Nesom, Guy L. (2021). "Taxonomy of Tiarella (Saxifragaceae) in the eastern USA" (PDF). Phytoneuron. 31: 1–61. (A shortened version of Nesom's paper was published by the North Carolina Botanical Garden in 2022.)
For more general information about Tiarella, see: Observing and identifying Foamflowers in eastern North America
Comentarios
After reviewing the observations of Tiarella in Georgia, here are some comments.
Unlike Tiarella austrina, the flowering stem of Tiarella nautila is consistently leafy, often with two leaves per stem. The lower stem leaf can be quite large. In general, both leaves seem to be larger than the single stem leaf of T. austrina.
The most remarkable feature of Tiarella nautila is its branched stem. Many plants have a secondary stem growing from the axil of the lower stem leaf. A few plants have multiple branches, with branch points independent of the stem leaves. When I first noticed a branched stem, I was shocked, thinking to myself that this couldn't be Tiarella. As it turns out, branched stems are fairly common on Tiarella nautila in Georgia.
Although the flowers of the various taxa are similar, these striking features leave no doubt that Tiarella nautila is distinct from other taxa in genus Tiarella.
Agregar un comentario