Vascular Plants of North Carolina
Account for Southern Bluet - Houstonia micrantha   (Shinners) Terrell
Members of Rubiaceae:
Members of Houstonia with account distribution info or public map:
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Section 6 » Family Rubiaceae
Author(Shinners) Terrell
DistributionDiscovered by Brian England in 2017-18 in Wake County (fide Weakley 2018); photos have been added to this website, and a specimen now is present at NCU. Another specimen, from 2023, was collected by Becky Dill in Anson County. To be looked for elsewhere, as it is probably easily passed over as a white-flowered H. pusilla.

Native west of the Appalachians from TN to MO, south to northwestern FL and eastern TX. Adventive in central NC.
AbundanceVery rare.
Habitat"Roadsides and other disturbed areas." In its native range, it is found in sandy soils, around flatrocks, and other sunny and sandy places.
PhenologyFlowering and fruiting February-April.
IdentificationThis tiny species is very similar to H. pusilla, but the corollas are white and 2.0-5.5 mm long (vs. corollas lavender or blue-violet and 3.5-10 mm in H. pusilla). Also, H. micrantha has calyx lobes about as long as the corolla tube, at times visible from above; H. pusilla has short calyx lobes.
Taxonomic Comments
Other Common Name(s)
State RankSE
Global RankG4G5
State Status
US Status
County Map - click on a county to view source of record.
Photo Gallery
Bryan EnglandWilkerson Nature Preserve, Raleigh. 2017. Notice how in side view all the (tiny!) flowers have calyx lobes as long or longer than the corolla tube. WakePhoto_non_natural
Bryan EnglandWilkerson Nature Preserve, Raleigh. WakePhoto_non_natural
Bryan EnglandWilkerson Nature Preserve, Raleigh. You’ll notice the calyx lobes on this one are so long, they are not only longer than the corolla tube, they are almost as long as the petals! (This is an extreme case – they aren’t always this long.) WakePhoto_non_natural
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