Foamflowers in Kentucky

In November 2022, iNaturalist split Tiarella cordifolia into five species, two of which occur in Kentucky: Tiarella stolonifera and Tiarella wherryi. The ranges of the two species overlap in three counties in south-central Kentucky.

Distribution of Tiarella in Kentucky counties (overlap in bold):

• Tiarella stolonifera: Bell, Carter, Clay, Elliot, Estill, Floyd, Gallatin, Garrard, Greenup, Harlan, Jackson, Jessamine, Jefferson, Johnson, Kenton, Knott, Knox, Laurel, Lee, Leslie, Letcher, Lincoln, Madison, Martin, McCreary, Menifee, Perry, Pike, Powell, Pulaski, Rockcastle, Rowan, Whitley, Wolfe, Woodford
• Tiarella wherryi: Clinton, Cumberland, Edmonson, Hart, Laurel, McCreary, Metcalfe, Pulaski, Wayne

Observations of Tiarella stolonifera in Kentucky:

• Observations of Tiarella stolonifera in an expected county in KY
• Observations of Tiarella stolonifera in an unexpected county in KY

Observations of Tiarella wherryi in Kentucky:

• Observations of Tiarella wherryi in an expected county in KY
• Observations of Tiarella wherryi in an unexpected county in KY

Tips for identification of Tiarella species:

• Identification of Tiarella stolonifera
• Identification of Tiarella wherryi

Tiarella stolonifera is distinguished by the presence of a stolon, which Tiarella wherryi does not have. Since stolon production is seasonal, it is sometimes helpful to examine the leaves. A basal leaf of Tiarella wherryi is usually longer than wide. with acute-acuminate lobes and a prominently extended terminal lobe. On the other hand, a basal leaf of Tiarella stolonifera usually has obtuse to rounded lobes and a terminal lobe that is not prominently extended.

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

Posted on December 18, 2022 07:51 PM by trscavo