Square-stalked St John's-wort - Hypericum tetrapterum
Short to tall erect hairless plant. Stems square, with four narrow wings, spreading and rooting at the base. Leaves opposite, rounded to oval with translucent dots. Flowers pale yellow, 9 to 10 mm, many in a spreading panicle.
Indicator Species - Leicestershire, Leicester & Rutland Local Nature Recovery Strategy.
Other St.John's-worts. See ID Aids below.
Petals pale yellow; small flowered; stems with 4 broad wings
The St John's Wort (Hypericum) family are attractive, yellow-flowered perennials. They can look confusingly similar but can be distinguished by careful examination of key features. A hand-lens may be required (depending how good your eyesight is!). The leaf perforations are visible as translucent dots if the leaf is held up to the light.
A photo of the plant in its habitat
Damp places, marshes, pond and river margins.
June to September.
Perennial.
Fairly common throughout Britain.
Fairly common in Leicestershire and Rutland. In the 1979 Flora survey of Leicestershire it was found in 310 of the 617 tetrads.
Graham Calow
Wykin Canal Towpath
31 July 2015
Graham Calow
Wykin Canal Towpath
26 June 2015
square stem
Graham Calow
Wykin Canal Towpath
26 June 2015
David Nicholls
Cloud Wood
07 July 2012
David Nicholls
Hill Hole
27 May 2016
Graham Calow
Wykin Canal Towpath
31 July 2015
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Species profile
- Common names
- Square-Stalked St. John's-Wort, Square St. John's Wort, Square-stalked St John's-wort
- Species group:
- flowering plant
- Kingdom:
- Plantae
- Order:
- Malpighiales
- Family:
- Hypericaceae
- Records on NatureSpot:
- 88
- First record:
- 23/04/2007 (Dave Wood)
- Last record:
- 30/07/2025 (Smith, Peter)
Total records by month
% of records within its species group
10km squares with records
The latest images and records displayed below include those awaiting verification checks so we cannot guarantee that every identification is correct. Once accepted, the record displays a green tick.
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Latest images
Latest records
Steve Harris
Burbage Common
27/07/2017
Fomoria septembrella
The larva of the moth Fomoria septembrella mines the leaves of Hypericum species, most commonly Perforate St John's-wort at first in a narrow gallery, later becoming a blotch mine.
Euspilapteryx auroguttella
The larva of the moth Euspilapteryx auroguttella mines the leaves of various Hypericum species such as St John's-worts initially in a lower surface gallery and then into a blotch, becoming a small narrow tentiform mine lined with silk. Later on the larva feeds and pupates in a leaf margin folded down.