GENUS 4. 



ST. JOHN'S-WORT FAMILY. 



537 



4. TRIADENUM Raf. Med. Rep. (II.) 5: 352. 1808. 



[ELODEA Pursh, Fl. Am. Sept. 360. 1814. Not Michx. 1803, nor Elodes 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. i. T. virginicum. 



Leaves short-petioled ; flower-clusters nearly sessile. 2. T. petiolatum. 



i. Triadenum virginicum (L.) Raf. Marsh 

 St. John's-wort. Fig. 2903. 



Hypericum virginicum L. Sp. PI. Ed. 2, 1104. 1763. 

 Hypericum campanula turn Walt. Fl. Car. 191. 1788. 

 Elodea cainpanulata 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, i-ij high. Leaves sessile or cordate- 

 clasping, ovate or oblong, i'-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, dis- 

 tinct; capsule oblong, 4'-$' long, acute, red-purple. 



In swamps, Newfoundland to Florida, west to Mani- 

 toba, Nebraska and Louisiana. Also in northeastern 

 Asia. Ascends to 2600 ft. in the Catskills. July-Sept. 



Triadenum longifolium Small, differing by longer 

 leaves, narrowed at the base, inhabits the Southern 

 States and ranges north into western Kentucky. 



2. Triadenum petiolatum (Walt.) Brit- 

 ton. Larger Marsh St. John's-wort 

 Fig. 2904. 



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 I' long, pale beneath; flower- 

 clusters axillary and terminal, sessile or very 

 short-peduncled. 



In swamps, New Jersey and Maryland to Flor- 

 ida, Indiana, Missouri, Arkansas and Louisiana. 

 July-Aug. 



Family 88. ELATINACEAE Lindl. Nat. Syst. Ed. 2, 88. 1836. 



WATER- WORT FAMILY. 



Low herbs, sometimes woody in tropical regions, with opposite or verticillate 

 stipulate entire or serrate leaves, and small axillary solitary or fascicled flowers. 

 Flowers regular, perfect. Sepals 2-5, imbricated. Petals the same number, 



