St. Andrew’s Cross

Hypericum hypericoides (formerly Ascyrum hypericoides)

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Illustration of St. Andrew's cross leaves, flowers, fruit.
St. Andrew's cross, Hypericum hypericoides
Paul Nelson
Family

Clusiaceae (St. John’s-worts)

Description

St. Andrew's cross is a small shrub with smooth, reddish bark that peels away in thin strips or flakes.

Flowers are bright lemon yellow; the 4 petals form an oblique cross; there are 4 sepals, of which 2 are large and 2 extremely small; with many stamens. Blooms July–October.

Leaves are opposite, sessile, lighter green below, narrowed at the base, to 1 inch long.

Fruits are ovoid capsules, widest at or below the middle, tapered to a short beak, flattened, with numerous seeds.

Of the two varieties in the state, the more common, var. multicaule, grows only to about 1 foot tall; it is bushy and branches at the base. Var. hypericoides is taller and doesn’t branch at the base, though it branches well above ground level.

Similar species: Missouri has 14 species of Hypericum. All have opposite, simple, entire leaves with small resin dots, flowers with 4 or 5 yellow petals, 4 or 5 sepals, many stamens, and 1 pistil. Many are small shrubs, with twigs often angled or 2-winged. The capsules have numerous seeds.

Size

Height: from 4 inches to 2 feet; sometimes nearly 5 feet tall.

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Photo of St. Andrew’s cross flower with foliage.
St. Andrew’s Cross
St. Andrew’s cross is easily identified by its distinctive X-shaped flowers. Look for it in dry, open woods and cut-over woodlands.

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Photo of St. Andrew’s cross showing branches with flowers and leaves.
St. Andrew’s Cross
St. Andrew’s cross typically has its 4 yellow petals arranged in an oblique X.

st._andrews_cross_fruits_11-3-14.jpg

Photo of St. Andrew’s cross showing fruits.
St. Andrew’s Cross (Fruits)
The fruits of St. Andrew’s cross are ovoid capsules, widest at or below the middle, flattened, containing numerous seeds.

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Photo of St. Andrew’s cross, a shrubby plant.
St. Andrew’s Cross
There are two varieties of St. Andrew’s cross in Missouri. Var. hypericoides doesn’t branch at the base, but it branches above ground level.
Habitat and conservation

Bottomland forests, rich to dry upland forests, banks of streams and rivers, occasionally margins of ponds and lakes; also roadsides and open, disturbed areas, usually on acidic or sandy substrates. Because the flowers are not abundant or very showy, this species is often overlooked.

image of St. Andrew's Cross distribution map
Distribution in Missouri

Scattered south of the Missouri River.

Human connections

This native plant can be used as a wildflower in rock gardens, though it is not winter hardy in northern Missouri. The name comes from the flower shape. According to legend, St. Andrew the Apostle was crucified on an X-shaped cross. This shape, called a saltire, is used repeatedly in European heraldry, flags, and signs.

Ecosystem connections

Deer browse the foliage, and a variety of insects visit the flowers.