Vascular Plants of North Carolina
Account for Azure Bluet - Houstonia caerulea   L.
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Section 6 » Order Rubiales » Family Rubiaceae
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DistributionEssentially throughout the state, but absent along the immediate coast.

This is a widespread Eastern species, found from eastern Canada south to northern FL and LA.
AbundanceCommon to very common across the state, though mainly frequent to common in the mountains, and scarce toward the coast.
HabitatThis is a very familiar species of dry to mesic clay soil, typically where there is little competition -- wooded borders, fields, openings in upland woods, powerline clearings, and many other places, including lawns.
PhenologyBlooms from March to May, and fruits from May to June.
IdentificationThis is a tiny and very slender species, a welcome harbinger of spring, despite its very small size. It grows only to about 4" tall, with a cluster of small, rounded basal leaves. There are only one to several tiny pairs of opposite stem leaves, each oblanceolate but barely 1/5" long. The top of the stem, or any of the few branches, contains the familiar bluet flower -- 4 spreading light blue petals with a yellow eye. The spread of the flower is about 2/5" across. Usually, many will be found blooming in a small area. H. pusilla is somewhat similar, but even smaller, and it has a dark red eye and a more medium blue to lavender blue flower. H. serpyllifolia, a mountain plant, can grow near this species, but it has a creeping stem that sends up flowering stalks, and it has a richer blue flower.
Taxonomic CommentsA few references have this and other Houstonia species in the genus Hedyotis; most do not.

Other Common Name(s)Quaker Ladies, Innocence, Common Bluet, Little Bluet, Bluets. The first two are quirky and idiosyncratic.
State RankS5
Global RankG5
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