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 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 thinly papery leaves are up to long and across and paler underneath.