Perennial or annual herbs, with alternate usually entire leaves, and axillary or terminal, yellow or greenish (lowers. Stems erect as ascending, sometimes angled, or winged. Calyx-tube cylindric, obpyramidal or top-shaped, not prolonged beyond the ovary, 3-5-lobed (usually 4-lobed), the lobes generally persistent. Petals usually 4, sometimes none, inserted under the margin of the disk. Stamens usually 4, inserted with the petals; filaments short. Ovary 4-5-celled; stigma capitate or 4-lobed. Capsule terete, ribbed or winged, crowned with the calyx-lobes, many-seeded, septicidally or irregularly dehiscent, or opening by an apical pore. [Named in honor of C. G. Ludwig, 1709-1773, Professor of Botany at Leipsic]

About 25 species, natives of warm and temperate regions, most abundant in North America. Besides the following about 12 others occur in the southern and southwestern states. Type species: Ludwigia alternifolia L.

Flowers inconspicuous; petals none, or small, yellowish or greenish; valves of the capsule separating from the terminal disk. Capsules subglobose or top-shaped.

Bractlets at the base of the calyx minute, or none; capsule subglobose, finely pubescent.

1.

L. sphaerocarpa.

Bractlets at the base of the calyx linear, about equalling the capsule; capsule top-shaped,

glabrous.

2.

L. polycarpa.

Capsules cylindric or obpyramidal.

Capsules cylindric.

3.

L. glandulosa.

Capsules obpyramidal.

Capsules as long as broad, or broader, the angles winged.

4.

L. alata.

Capsules several times longer than broad, the angles obtuse.

5.

L. linearis.

Flowers showy, peduncled; petals large, bright yellow; capsules opening by an apical pore.

Plants hirsute; capsules bristly pubescent.

6.

L. hirtella.

Plants glabrous; capsules glabrous.

7.

L. alternifolia.

I. Ludwigia Sphaerocàrpa Ell. Globe-Fruited Ludwigia

Fig. 3016

Ludwigia rudis Walt. Fl. Car. 89. 1788. ?

Ludwigia sphaerocarpa Ell. Bot. S. C. 1: 213. 1817.

Erect, branching, generally finely pubescent, stoloniferous, 2°-3° high, the lower part of the stem clothed with aerenchyma when growing in water. Leaves alternate, sessile, those of the stem and branches lanceolate, acute at both ends, 2'-4' long, scabrous and minutely denticulate, those of the stolons obovate; flowers solitary, sessile, greenish, about 1 1/2" broad; bractlets at base of calyx minute or none; calyx-lobes triangular-ovate, acute; petals commonly none; capsule subglobose, about 2" high, scarcely longer than the calyx-lobes, finely pubescent.

In swamps, eastern Massachusetts to southern New York and Florida, west to Louisiana. July-Sept.

I Ludwigia Sphaeroc Rpa Ell Globe Fruited Ludwigia 1358