Vor. II.] EVENING-PRIMROSE FAMILY. 477 
at the base at a right angle to the peduncle, about as long as the persistent calyx-segments, 
crowned by a prominent 4-lobed stylopodium. [Derivation as in the following genus. ] 
A monotypic genus of the southeastern United States. 
1. Ludwigiantha arcuata (Walt.) Small. 
Curved-podded Ludwigiantha. (Fig. 2556. ) 
Ludwigia arcuata Walt. Fl. Car. 89. 1788. 
Ludwigtantha arcuata Small, Bull. Torr. Club, 24: 
178. 1897. 
Creeping or floating, rooting at the nodes, gla- 
brous or nearly so, little branched, 3/-12’ long. 
Leaves opposite, oblanceolate, sessile, leathery, 
smooth, obtusish at the apex, narrowed at the 
base, 6/’-12’’ long; flowers axillary, solitary, bright 
yellow, 4/’-6’’ broad on filiform, 2-bracted pedun- 
cles much longer than the leaves; calyx-lobes 
linear-lanceolate, acuminate, shorter than the 
obovate petals; capsule club-shaped, somewhat 
curved, glabrous, about 4/’’-5’’ long, equalling or 
slightly longer than the calyx-lobes. 
In swamps, Virginia to Florida. May-July. 
3. LUDWIGIA L. Sieh JG cei, UGE. 
Perennial or annual herbs, with alternate usually entire leaves, and axillary or terminal, 
yellow or greenish flowers. Stems erect or 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; fllaments 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 to others occur in the southern and southwestern States. 
Flowers i inconspicuous; petals none, or small, yellowish or greenish; valves of the capsule separat- 
ing from the terminal disk. 
Cranes subglobose or top-shaped. 
Bractlets at the base of the calyx minute, or none; capsule subglobose, ney, pubescent. 
1. L. sphaerocarpa. 
Bractlets at the base of the calyx linear, about equalling the capsule; capsule top-shaped, 
glabrous. 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. 
1. Ludwigia sphaerocarpa Ell. Globe- 
fruited Ludwigia. (Fig. 2557.) 
Ludwigia rudis Walt. Fl. Car. 89. 1788. ? 
Ludwigia sphaerocarpa EM. 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. Leavesalternate, sessile, those ofthe 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 114’’ 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 and southern 
New York to Florida, west to Louisiana. July-Sept. 
