This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Not Michx. 1803, nor Elodcs Adans. 1763.] Perennial marsh herbs, with opposite entire oblong-oval or ovate leaves, and pink or greenish purple flowers in terminal cymes, or also axillary. Calyx of 5 equal persistent sepals. Petals 5, not contorted, imbricated in the bud. Stamens 9, or sometimes more, in 3 sets, the sets alternating with 3 large hypogynous glands. Ovary 3-celled; styles 3. Capsule oblong-conic, much longer than the sepals. [Greek, three glands.]
Three species, natives of eastern North America. Type species: Hypericum virginicum L.
Leaves sessile; flower-clusters peduncled.
Leaves short-petioled; flower-clusters nearly sessile.
Hypericum virginicum L. Sp. Pl. Ed. 2, 1104. 1763. Hypericum campanulatum Walt. Fl. Car. 191. 1788. Elodea campanulata Pursh, Fl. Am. Sept. 379. 1814. Elodea virginica Nutt. Gen. 2: 17. 1818. Triadenum virginicum Raf. Fl. Tell. 3: 79. 1836.
Glabrous, erect or ascending, nearly simple, often reddish, 1°-1 1/2° high. Leaves sessile or cordate-clasping, ovate or oblong, 1'-3' long, 9"-12" wide, very obtuse, sometimes emarginate, glaucous beneath, black-dotted; flowers 6"-8" broad, in axillary and terminal peduncled leafy clusters; sepals ovate or lanceolate. acute, shorter than the straight petals; stamens 9 or more, united in 3 sets; styles 3, distinct; capsule oblong, 4'-5' long, acute, red-purple.
In swamps, Newfoundland to Florida, west to Manitoba, Nebraska and Louisiana. Also in northeastern Asia. Ascends to 2600 ft. in the Catskills. July-Sept.
Triadenum longif˛lium Small, differing by longer leaves, narrowed at the base, inhabits the Southern States and ranges north into western Kentucky.
Hypericum petiolatum Walt. Fl. Car. 191. 1788.
Elodea petiolata Pursh, Fl. Am. Sept. 379. 1814.
Triadenum petiolatum Britton; Britt. & Brown, 111. Fl. 2: 437. 1897.
Similar to the preceding species, but often more branched and taller; leaves generally longer (2-5'), petioled, or the upper sessile, not clasping, often narrowed at the base with petioles up to 1/2' long, pale beneath; flower-clusters axillary and terminal, sessile or very short-peduncled.
In swamps, New Jersey and Maryland to Florida, Indiana, Missouri, Arkansas and Louisiana. July-Aug.