8. Hypericum majus (A. Gray) Rusby (greater St. John’s wort)

H. canadensis L. var. majus A. Gray

Pl. 360 l, m; Map 1568

Plants perennial herbs, sometimes with short rhizomes. Stems 10–60 cm long, erect, angled or narrowly ridged below each leaf, at least toward the tip, green, sometimes purplish-tinged. Leaves not jointed at the base, ascending or loosely ascending. Leaf blades 10–45 mm long, 3–10 mm wide, lanceolate to narrowly elliptic or narrowly oblong, rounded or bluntly to more commonly (in at least the uppermost leaves) sharply pointed at the tip, narrowed or narrowly rounded at the base, the uppermost leaves sometimes slightly clasping the stem, the margins flat, herbaceous to slightly leathery in texture, with mostly 5 or 7 main veins from the base, the surfaces with inconspicuous, minute, yellowish brown to dark green or black resinous dots, the upper surface green, the undersurface green, not glaucous. Inflorescences appearing as panicles of 5–30 flowers, rounded to more or less flat-topped in outline. Flowers actinomorphic. Sepals 5, all more or less similar in size and shape, 4.0–6.5 mm long, usually becoming slightly enlarged at fruiting, lanceolate, lacking noticeable yellowish brown or black dots, lines, and/or streaks. Petals 5, 3.5–5.5 mm long, oblanceolate, bright yellow, occasionally with reddish veins, lacking noticeable yellowish brown or black dots, lines, and/or streaks, usually shed by fruiting. Stamens 14–20, the filaments sometimes irregularly spaced but usually not fused into groups. Ovary 1-locular or appearing partially 3-locular by intrusion of the parietal placentae into the locule. Styles 3, free above the base, more or less spreading, the stigmas narrowly capitate. Fruits 5–7 mm long, at maturity about as long as the sepals, ovoid-conical, widest well below the midpoint, tapered to the persistent styles, more or less circular in cross-section, usually maroon at maturity. Seeds numerous, 0.5–0.7 mm long, the surface with a network of fine to coarse ridges and pits, appearing longitudinally ribbed, light brown to brown. 2n=16. July–September.

Uncommon, known thus far only from a single specimen from Sullivan County (northern U.S. south to Pennsylvania, Oklahoma, and Washington; Canada). Open slopes in ravines.

As noted by Yatskievych (1990), Steyermark (1963) incorrectly determined the Missouri plants as H. canadense, a closely related species that occurs only to the north and east of the state. It is most easily distinguished from H. majus by its 1- or 3-nerved, linear to narrowly oblanceolate leaves that are tapered at the base.