Phacelia covillei S. Wats. ex A. Gray

Locations of Phacelia covillei S. Wats. ex A. Gray in Virginia

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Detail

Family
Boraginaceae
Botanical Name
Phacelia covillei S. Wats. ex A. Gray
Common Name
Coville’s Phacelia
Synonym(s)
Flora of Virginia Name/Status
Phacelia covillei S. Wats. ex Gray
Comments
This species has often been considered an eastern cytotype of Phacelia ranunculacea (Nutt.) Constance, which occupies similar habitats of the sc. U.S. in the lower Ohio and Mississippi River drainages. Sewell and Vincent (2006, Castanea 71: 192-209) found that the two taxa differ in chromosome number, subtle but consistent morphological characters, and overall distribution. However, morphological differences are fairly minor and the geographic split isn't as clean as one might hope, as there are populations of P. covillei in the Ohio River drainage, as well as the Atlantic Piedmont. Nevertheless, Sewell and Vincent present a reasonable case for two species, especially since the different ploidy levels would prevent interbreeding.

Phacelia covillei has a remarkably disjunct distribution, being found in three more or less discrete areas: the c. NC and sc. VA Piedmont (Cape Fear, Tar, and Roanoke Rivers); the Potomac River Fall Zone of n. VA, sc. MD, and D.C.; and the Ohio River drainage in sw. WV, s. OH, sw. IN, and se. IL. There is an additional disjunct population in Texas County, MO.
Habitat
Rich, well-drained floodplain forests and adjacent slope forests. Rare and known only from the Potomac River in Fairfax County and the City of Arlington (n. Piedmont) and the Hyco River in Halifax County (s. Piedmont); however, it is locally abundant in both areas.
Native Status
Native

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