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.
Hypericum tetrapterum is a rhizomatous, glabrous perennial plant growing to about 60cm in height. 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 yellow flowers are 9-13mm diameter and there may be black glands on the five petals and sepals, as well as on the leaves.:340
Hypericum tetrapterum is common in damp habitats throughout Europe. 
|Wikimedia Commons has media related to Hypericum tetrapterum.|
|This Malpighiales article is a stub. You can help Wikipedia by expanding it.|