Hypericum perforatum L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Branched perennial herb 7–15 dm; lvs lanceolate to elliptic, 4–10 cm, acute or obtuse, sessile and sometimes clasping; fls few, chiefly solitary at the ends of the branches, 4–6 cm wide; stamens very numerous, united at base into 5 sets; styles 5, united below but not persistent; stigmas capitate; fr ovoid, 15–30 mm, 5-locular. Moist soil; Que. to Minn., s. to Pa., Ind., and Kans. June–Aug. (H. ascyron, misapplied)
common St. John's wort