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..
Low decumbent or erect somewhat succulent mainly semi-aquatic herbs, with petioled opposite or alternate crenate leaves, with no stipules. Flowers minute, greenish, axillary or terminal, solitary or clustered, perfect. Calyx-tube urn-shaped or obconic, adnate to the ovary, its limb 4-5-lobed. Petals none. Stamens 8-10 (rarely 4-5), inserted on the margin of a disk; filaments short. Ovary 1-celled, flattish, 2-lobed; styles 2, short, recurved; ovules ∞. Capsule membranous, short, inversely cordate or 2-lobed, 2-valved above, few- or many-seeded. Seed-coat muricate or pilose. [Greek, golden spleen, from some reputed medicinal qualities.]
About 15 species, natives of the north temperate zone and southern South America. Besides the following, 2 others occur in northwestern America. Type species: Chrysosplenium opposi-tifolium L.
Lower leaves opposite; flowers mostly solitary.
Leaves all alternate; flowers corymbose.
Stems slender, decumbent, forked above, glabrous or very nearly so, 3'-8' long. Lower leaves opposite, the upper often alternate, broadly ovate, orbicular or somewhat reniform, obtuse or truncate at the base, rounded at the apex, crenate or obscurely lobed, 2"-10" wide; flowers sessile, axillary, usually solitary, about 1" broad; calyx-lobes commonly 4, yellowish, or purplish within; stamens commonly 8; anthers orange-red.
Chrysosplenium iowense Rydb.; Britton, Man. 483. 1901.
Flowering stems erect, glabrous or pubescent, 2'-6' high, branched above. Leaves all alternate, the basal ones long-petioled, reniform, or cordate, often pubescent on the upper surface, 3"-18" wide, or crenate with 5-11 rather broad lobes; flowers mainly terminal, corymbose; calyx-lobes commonly 4, orange-yellow within; stamens usually 8.
On wet mossy slope, Decorah, Iowa. May-June. Confused with Chrysosplenium alternifolium of Europe, in our first edition.