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Houstonia caerulea

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Houstonia caerulea
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Gentianales
Family: Rubiaceae
Genus: Houstonia
H. caerulea
Binomial name
Houstonia caerulea

Houstonia caerulea, commonly known as azure bluet, Quaker ladies, or bluets,[2] is a perennial species in the family Rubiaceae.[1] It is native to eastern Canada (Ontario to Newfoundland) and the eastern United States (Maine to Wisconsin, south to Florida and Louisiana, with scattered populations in Oklahoma).[3] It is found in a variety of habitats such as cliffs, alpine zones, forests, meadows and shores of rivers or lakes.[4]


Azure Bluet (Houstonia caerulea) in Pennsylvania
Azure Bluet (Houstonia caerulea) in Pennsylvania, close-up

Houstonia caerulea is a perennial herb[2] that produces showy flowers approximately 1 cm (0.39 in) across. These flowers are four-parted with pale blue petals and a yellow center. The foliage is a basal rosette with spatula-shaped leaves.[2] Stems are up to 20 cm (7.9 in) tall with one flower per stalk. Leaves are simple and opposite in arrangement with two leaves per node along the stem.[4] It thrives in moist acidic soils in shady areas, growing especially well among grasses.[5]



  1. ^ a b Justice, William S.; Bell, C. Ritchie; Lindsey, Anne H. (2005). Wild Flowers of North Carolina (2. printing. ed.). Chapel Hill, NC: Univ. of North Carolina Press. p. 236. ISBN 0807855979.
  2. ^ a b c "Lady Bird Johnson Wildflower Center - The University of Texas at Austin". www.wildflower.org. Retrieved 2021-10-13.
  3. ^ Biota of North America Program
  4. ^ a b "Houstonia caerulea (little bluet): Go Botany". gobotany.nativeplanttrust.org. Retrieved 2021-11-04.
  5. ^ Scoggan, H. J. 1979. Dicotyledoneae (Loasaceae to Compositae). Part 4. 1117–1711 pp. In Flora of Canada. National Museums of Canada, Ottawa.

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