Hypericum tetrapterum

Hypericum tetrapterum
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Malpighiales
Family:	Hypericaceae
Genus:	Hypericum
Section:	Hypericum sect. Hypericum
Subsection:	Hypericum subsect. Hypericum
Series:	Hypericum ser. Hypericum
Species:	H. tetrapterum
Binomial name
Hypericum tetrapterum Fries [1]
Synonyms [2]
Hypericum acutum subsp. tetrapterum(Fr.) Maire Hypericum quadrangulum subsp. tetrapterum(Fr.) Hook.f. Hypericum quadrangulum var. tetrapterum(Fr.) Borg Hypericum quadrialatumWahlb. Hypericum tetrapterum var. genuinumCout.

Hypericum tetrapterum (syn. H. quadrangulum) is a herbaceous perennial plant species in the flowering plant family Hypericaceae. Its common names include St. Peter's wort, Peterwort, square stemmed St. John's wort, and square stalked St. John's wort.

Description

Hypericum tetrapterum is a rhizomatous, glabrous perennial plant growing up to 1.2 m (3 ft 11 in) in height. ^{[1] [3] : 340} The stems are square in cross section, with conspicuous wings at the corners. The leaves are in opposite pairs, simple and entire, and have many translucent glandular dots. The thinly papery leaves are up to 40 mm (2 in) long and 24 mm (0.9 in) across and paler underneath. ^[1] The flowers are produced in flowerheads of 10–30 flowers (up to 70), each flower 10–15 mm (0.39–0.59 in) in diameter with 5 pale yellow petals and 5 sepals. ^[1] There may be black glands on the petals and sepals, as well as on the leaves. ^[3]

Distribution and habitat

Hypericum tetrapterum is native to temperate Europe, the Mediterranean basin countries of Europe, north Africa, and western Asia, and the Caucasus, Iraq, and Iran. ^[2] It is common in damp habitats such as marshes, streamsides, open ditches, meadows, and springs. ^{[4] [1]}

Varieties

Three varieties are accepted. ^[2]

• Hypericum tetrapterum var. anagallifoliumBoiss. – southern Turkey to Israel
• Hypericum tetrapterum var. corsicum(Steud.) Boiss. – Corsica
• Hypericum tetrapterum var. tetrapterum – entire range

References

1. "Hypericum tetrapterum Fr". hypericum.myspecies.info. Retrieved 2018-10-26.
2. "Hypericum tetrapterum Fr". Plants of the World Online . Royal Botanic Gardens, Kew . Retrieved 10 February 2025.
3. Stace, C. A. (2010). New Flora of the British Isles (Third ed.). Cambridge, U.K.: Cambridge University Press. ISBN   9780521707725.
4. "Hypericum tetrapterum L." Retrieved 19 August 2015.