Houstonia caerulea (Bluets)

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Houstonia caerulea L.

Bluets, quaker ladies, azure bluet, bluet

Kingdom	Plantae	Plants, but not fungi, lichens, or algae
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Magnoliophyta	Flowering plants, also known as angiosperms
Class	Magnoliopsida	Dicotyledons—plants with two initial seed leaves
Subclass	Asteridae	A large class that encompasses asters
Order	Gentianales	Gentians, coffee, gardenias, frangipani, many others
Family	Rubiaceae	Coffee, madder, and bedstraw family
Genus	Houstonia	Named for English botanist Dr. William Houston
Species	caerulea	“Blue,” from the same root as the English word “cerulean”

About plant names...

Azure bluets are cheerful natives of central and eastern North America. The name “Quaker ladies” may be a reference to their prim bonnet-like flowers. They prefer moist meadows, lawns, fields, and roadsides, and other disturbed habitats; as well as cliffs, ledges, and freshwater shores.

Plants: Bluets are virtually invisble when not flowering, at less than 4" (10 cm) in height, but they make a big impact when they are, appearing in dense, attractive colonies.

Leaves: Leaves at the base of the flowers are relatively large, and oblanceolate to spatulate; while those on the stem are much smaller and similarly shaped, or sometimes linear.

Flowers: You would think bluets would be blue, and usually they are pale or darker blue-violet in color, but sometimes they are so pale they are almost white. They are about ¼" (6.3 mm) in diameter, and appear from April to early July.

Fruits: Flattened fruits are ¹/₁₆-⅛" (3-4 mm) wide, and much broader than long. Seeds are globular.

Online References:

Missouriplants.com

Www.jeffpippen.com

Illinois Wildflowers

The Lady Bird Johnson Wildflower Center

The Connecticut Botanical Society's Connecticut wildflowers site

The University of Wisconsin's Robert W. Freckmann Herbarium

The Vanderbilt University Bioimages web site

Southeastern Flora, the Southeastern U.S. Plant Identification Resource

The Wisconsin Department of Natural Resources

The tiny leaves make even the ¼-inch flower look big. · 5/19/2021 · Heath Trail, Highland Green, Topsham, Maine
≈ 2½ × 3" (6.3 × 8.4 cm)

5/6/2021 · Tarbox Preserve, Topsham, Maine
≈ 3½ × 3½" (9.7 × 9.5 cm)

5/17/2021 · Bijhouwer Forest, Phippsburg, Maine
≈ 5 × 4" (13 × 10 cm)

5/11/2021 · Hackett and Minot Trails, Harpswell, Maine
≈ 7 × 4½" (18 × 12 cm)

5/15/2010 · Garden in the Woods, Framingham, Massachusetts
≈ 8 × 5" (19 × 13 cm)

8/28/2020 · Jack’s and Litchfield Trails, Chase Reserve, Brunswick, Maine
≈ 5 × 4½" (13 × 12 cm)

Hedyotis caerulea (L.) Hook.

Houstonia caerulea L. var. faxonorum Pease & A.H. Moore

Houstonia caerulea description by Thomas H. Kent, last updated 11 Jul 2023.

5/11/2013 · Townsend Wildlife Management Area, Townsend, Massachusetts
≈ 4½ × 6" (12 × 15 cm)

5/8/2021 · Carol Martin’s, Highland Green, Topsham, Maine
≈ 4½ × 7" (12 × 17 cm)

5/15/2010 · Garden in the Woods, Framingham, Massachusetts
≈ 6 × 4" (15 × 10 cm)

5/30/2014 · Townsend Wildlife Management Area, Townsend, Massachusetts
≈ 9 × 6" (22 × 15 cm)

4/21/2010 · Tom and Susan’s, Pepperell, Massachusetts
≈ 5 × 3½" (13 × 9.2 cm)

5/20/2012 · J. Harry Rich State Forest, Groton, Massachusetts
≈ 17 × 12" (44 × 29 cm)

The flowers are diminutive, at less than 1/4" across, but the leaves, usually hidden, are much smaller. · 5/15/2016 · Mt. Watatic, Ashby, Massachusetts

5/14/2023 · Cathance River Trails, Topsham, Maine

4/21/2010 · Tom and Susan’s, Pepperell, Massachusetts
≈ 6 × 5" (16 × 13 cm)

5/20/2012 · J. Harry Rich State Forest, Groton, Massachusetts
≈ 6 × 4½" (15 × 11 cm)

Range: Zones 3-8:

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