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Plants of the Eloise Butler Wildflower Garden

The oldest public wildflower garden in the United States

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Common Name
Long-leaved Bluet (Eyebright)

 

Scientific Name
Hedyotis longifolia (Gaertn.) Hook
Former Houstonia longifolia

 

Plant Family
Madder (Rubiaceae)

Garden Location
Historic, not extant

 

Prime Season
Early to Late Summer

 

 

There are a large number of species known as bluets or star violets in North America. Long-leaved Bluet is a native erect perennial forb growing on often top-branching stems from 3 to 10 inches high, frequently forming a nice clump. Stems are green to reddish green, 4-angled and can have hair on the angles.

The leaves are opposite, stalkless but not clasping, oblong to linear in shape, generally smooth but can have fine marginal hair. Margins are entire, blades taper to a point. There is a single mid-vein. Width is usually less than 1/4 inch the length can be 4 to 6x the width. There is a small triangular stipule at the base of each leaf pair connecting them. In the spring a basal rosette first forms, from which rises the flower stem and is sometimes whithered at flowering time.

The inflorescence is a terminal branched cluster (called a cyme) of 3+ short-stalked flowers.

The flowers are 4-parted, up to 1/3 inches wide when open. The corolla is tubular with 4 pointed petals widely spreading with fine hair in the corolla throat. The tube is much longer than the spreading part of the petals. The petals can range from pinkish to white in color. The outer calyx is green, cup shaped with 4 long pointed lobes (sepals). Flower stalks and calyx are without hair but can be very glandular, the glands being too small to see with the naked eye. There are 4 stamens, united at their base, then positioned alternate with the petals, and a style with 2 stigmas. Flowers vary in how they display these. Some have stamens with long filaments, exerted, with whitish to yellowish anthers, and with the style truncated inside the tube. Others have the stamens shortened and the style exerted. See photos and drawing below.

Fruit: Flowers mature to a rounded seed capsule with the remains of the 4 sepals attached. The seeds are round to ellipsoid shape, black, with a wrinkled surface.

 

Habitat: Long-leaved Bluet grows from a fibrous root system, sometimes forming a caudex. It prefers dry sunny locations and accepts poorer soils and acid soils but does best in richer soils. It spreads by re-seeding.

Names: The genus Hedyotis is an old term whose significance has been lost. It is derived from the Greek hedys, meaning 'sweet, and ous or otos for 'ear'. The species, longifolia, means 'long-leaved'. The older genus, Houstonia, was an honorary for William Houstoun (1695-1733), Scottish surgeon who collected many plants in Central America and the West Indies and his drawing are found in the British Museum. The author names for the plant classification are: ‘Gaertn.’ refers to Joseph Gaertner (1732-1791) German botanist, whose work on plant genetics by making back-crosses was very important and furthered later my Mendel. His major publication was De Fructibus et Seminbus Plantarum. When the species was added to Hedyotis, the name of ‘Hook.’ was added, which is for William Hooker, (1785-1865), English Botanist, author, collector, Professor of Botany at the University of Glasgow and the first director of the Royal Botanic Garden at Kew. His work on North American plants was mostly published in Flora Boreali-Americana.

See bottom of page for notes on the Garden's planting history, distribution in Minnesota and North America, lore and other references.

Plant group Drawing

Above: A nice clump of Long-leaved Bluet. Drawing from Britton & Brown Illustrated Flora of the Northern United States, Canada, and the British Possessions in 1896. Note the drawing of the two flowers showing the two stamen positions, then see photos below.

Below: The first photo shows the trumpet like floral tube with the short calyx. Note the protruding stigmas of the style. The second photo shows the alternate flower type with the style recessed and the stamens exerted. The reddish 4-angled stem shows hair on angles.

flower flower stem

Below: A typical flower cluster (a cyme), note the triangular stipules at the base of the leaf pair - detailed in 2nd photo.

flower clusterleaf stipule

Below: The inflorescence forming at the top of a stem. Note the leaves on this plant have fine marginal hair.

plant top and leaf

Below: Seeds. 1st photo - the small round seed pod with the pointed lobes of the sepals remaining. 2nd photo - The seeds are round to ellipsoid shape, black, with a wrinkled surface.

seedpod seeds

Notes:

Eloise Butler first introduced Long-leaved Bluets to the Wildflower Garden on Aug. 25, 1916 with plants she obtained at Taylor's Falls, MN. They were still in the Garden at the time of Martha Crone's 1951 census but are now no longer extant. This species is primarily found in the eastern half of North America, extending west to Alberta in Canada, but excluding the Maritime Provinces. In Minnesota it is found in about half the counties, more concentrated in the eastern and central part of the state with most absences in the western and southwestern parts. Minnesota is on the western edge of its ranges in the U.S. This is the only species of Hedyotis (or the older Houstonia) found in MN. It is on the threatened or endangered list in several eastern states and considered lost in Rhode Island.

References and site links

References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.

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