Vascular Plants of North Carolina
Account for Alternate Milkwort - Senega ambigua   (Nutt.) J.F.B. Pastore & J.R. Abbott
Members of Polygalaceae:
Members of Senega with account distribution info or public map:
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Section 6 » Family Polygalaceae
Author(Nutt.) J.F.B. Pastore & J.R. Abbott
DistributionSpecimens at NCU were annotated in April 2019, which verified most of the green counties on the map. This is necessary as this species has often been treated as a variety of Senega verticillata, and thus the website editors wanted some confirmation of specimens of these very similar species. The species is present over most of the Mountains, and at least most of the eastern Piedmont, with an odd absence or scarcity in the central and western portions of the Piedmont. Weakley's (2018) map shows it as occurring as "uncommon" in all three provinces, including the Coastal Plain, but there seem to be no confirmed specimens for the Coastal Plain.

This species has a wide Eastern range, from ME to MI, and south to GA and OK.
AbundanceUncommon in the Mountains and in the eastern Piedmont; very rare to rare in the intervening area. True relative abundance of this species compared with S. verticillata is somewhat unsettled, but the dichotomous range does seem to be real.
HabitatThis is a species of dry soil, usually in sunny places and in circumneutral soil conditions. It is found in fields, meadows, wooded borders, powerline clearings, and other similar places.
PhenologyBlooms from June to September, and fruits soon after flowering.
IdentificationThis is a very slender species with several branches above, like a few others in the genus. It grows only to about 8 inches tall. The lower stem leaves are usually whorled (3-5 leaves), but alternate on the upper parts of the stem and branches. All leaves are linear and short, about 3/4-inch long and very narrow. The racemes of slender clusters that top each branch are only about 1-2 inches long, with many very small greenish white to whitish flowers. The very similar S. verticillata has shorter racemes (averaging barely 1/2-inch to rarely 3/4-inch long), and nearly all of the stem leaves are in whorls. S. nuttallii has slender racemes but the flowers are pink and the raceme is not as slender as in these other two species.
Taxonomic CommentsSee above. RAB (1968) listed this taxon as P. verticillata var. ambigua.

All of the former Polygala species in NC have now been moved to the genus Senega in 2023.
Other Common Name(s)Whorled Milkwort (the common name for S. verticillata), Loose Milkwort
State Rank[S3]
Global RankG5T5? [G5?]
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