spotted St. Johnswort

(Hypericum punctatum)

               
Conservation Status

IUCN Red List

not yet assessed

 

No image available

NatureServe

N5 - Secure

SNR - Unranked

Minnesota

not listed

Wetland
Indicator
Status

Great Plains

FAC - Facultative

Midwest

FAC - Facultative

Northcentral & Northeast

FAC - Facultative

Nativity

Native

Occurrence

Locally common

Habitat

Dry or moist. Fields, woodland edges and openings. Usually in partial sun.

Flowering

June to August

     
Flower Color

Yellow

     
Height

20 to 40

     

Identification

This is an erect, perennial forb that rises on multiple stems from a woody rhizome. It can be 20 to 40 in height but is usually no more than 30 tall.

The stems are erect, hairless, leafy, and round in cross section. They have few if any branches below the inflorescence. They are green or red and are dotted with black glands.

The leaves are opposite, oblong-elliptic, and stalkless. The larger leaves are 1½ to 2 long and to wide. They are rounded to almost squared off at the tip and sometimes have a shallow notch at the tip. They are dotted with translucent glands visible when the leaf is held up to light. The upper surface is hairless. The lower surface is hairless and is dotted with many black glands. Between larger black glands there are numerous small, slightly paler, translucent spots. The margins are untoothed and dotted with many black glands.

The inflorescence is a branched cluster of many flowers at the end of the stem and a few curved flowering branches rising from nodes immediately below. The terminal clusters together with the curved flowering branches form a usually small and crowded, flat-topped or rounded array (cyme). Each flower is subtended by a linear, long, modified leaf (bract).

The flowers are small, 5 16 to in diameter. There are 5 sepals, 5 petals, 30 to 60 stamens, and 3 styles. The sepals are green, egg-shaped to oblong, 1 16 to long, and 132 wide. They are broadly or moderately angled with straight sides along the tip. They are erect in bud, bent backward in flower. They are heavily dotted with black glands. The petals are yellow, oblong to elliptic, asymmetric, to ¼ long, and about 1 16 wide. There are numerous amber to black dots all over the petals, not just near the margins. The petals shrivel and turn brown but remain attached as the fruit develops. The stamens are in 3 groups. The anthers are yellow. The styles are 1 16 to long. The stigmas are often reddish.

The fruit is a nearly round to egg-shaped, to ¼ long, 3-chambered capsule with numerous seeds.

 
Similar
Species

Common St. Johnswort (Hypericum perforatum) is a shorter plant, no more than 32 tall, and is more branched. The stems are strongly angled and have two small longitudinal ridges. The branches are sharply ridged below the base of each leaf. The leaves are smaller, no more than 1¼ long. The small translucent spots on the lower leaf surface are paler, more translucent. The inflorescence is larger and more open. The flowers are larger, up to 1 in diameter. The sepals are acuminate and have few if any black glands. The petals have black dots only near the margin.

Pale St. Johnswort (Hypericum ellipticum) has erect, unbranched stems and a few pale yellow flowers.


Distribution Distribution Map   Sources: 2, 3, 4, 5, 28.

Comments

What’s In a Name
The common name refers to the blooming period. The plant is usually in bloom on June 24, St. John’s Day.


Taxonomy

Family:

Hyperiaceae (St. Johnswort)

 

Tribe:

Hypericeae

 

Genus:

Hypericum

 

Section:

Hypericum

 
Synonyms

Hypericum subpetiolatum

 
Common
Names

spotted St. Johnswort

 

 

 

 

 

 

 

 

 

Glossary

Acuminate

Gradually tapering with concave sides to a sharply pointed tip.

 

Bract

Modified leaf at the base of a flower stalk or flower cluster.

 

Cyme

A branched, flat-topped or convex flower cluster in which the terminal flower opens first and the outermost flowers open last.

 

Linear

Long, straight, and narrow, with more or less parallel sides, like a blade of grass.

 

Node

The small swelling of the stem from which one or more leaves, branches, or buds originate.

 

Rhizome

A horizontal, usually underground stem. It serves as a reproductive structure, producing roots below and shoots above at the nodes.

 

Sepal

An outer floral leaf, usually green but sometimes colored, at the base of a flower.

 

Stigma

In plants, the portion of the female part of the flower that is receptive to pollen. In Odonata and Hymenoptera, a blood-filled blister or dark spot at the leading edge of each wing toward the tip, thought to dampen wing vibrations and signal mates. In Lepidoptera, an area of specialized scent scales on the forewing of some skippers, hairstreaks, and moths.

 

Style

Part of the pistil, usually a slender stalk, connecting the ovary to the stigma(s).

       
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