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.

1.

C. americanum.

Leaves all alternate; flowers corymbose.

2.

C. alternifolium.

14 Chrysosplenium Tourn L Sp Pl 398 1753 527

1. Chrysosplenium AmericÓnum Schwein. Golden Saxifrage. Water Carpet

Fig. 2185

Chrysosplenium oppositifolium Walt. Fl. Car. 140. 1788. Not L. C. americanum Schwein.; Hook. Fl Bor. Am. 1: 242. 1832.

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.

In wet, shaded places, Nova Scotia to the Saskatchewan region, south, along the mountains to Georgia, and to Ohio, Michigan and Minnesota. March-June.

2. Chrysosplenium Iowense Rydb. Iowa Golden Saxifrage

Fig. 2186

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.

2 Chrysosplenium Iowense Rydb Iowa Golden Saxifrag 528