Ludwigia peploides
Reinwardtia 6: 393. 1964.
Herbs or emergent aquatics, rooting at nodes, sometimes with fleshy, white pneumatophores at submerged nodes. Stems floating or creeping and ascending to erect, terete, 10–100(–300) cm, simple or branched, glabrous or sparsely to densely villous, hairs sometimes viscid on emergent distal stem. Leaves: stipules broadly ovate-deltate, 0.6–1.6 × 0.4–1 mm, succulent, apex acute or obtuse, gland-tipped, rarely divided into 3 parts; petiole flattened or narrowly winged, 0.2–6 cm; blade narrowly oblong or elliptic to ovate, broadly obovate, or orbiculate, (0.4–)1–10 × 0.4–4 cm, base narrowly cuneate or attenuate, margins entire, apex obtuse or rounded to acute, sometimes mucronate or glandular-mucronate, surfaces of floating leaves glabrous, those of emergent leaves glabrous to sparsely or densely strigillose at least adaxially; bracts scarcely reduced. Inflorescences on emergent stems sometimes in leafy racemes, flowers solitary in leaf axils; bracteoles (rarely absent), deltate, squamate, 0.5–1 × 0.5–1 mm, apex acute, attached near base or on lower 1/2 of ovary. Flowers: sepals narrowly deltate or lanceolate, 3–12 × 1.5–4 mm, apex acute or acuminate, surfaces glabrous or sparsely to densely hirtellous; petals yellow, obpyramidal,7–24 × 4–13 mm, apex mucronate or emarginate, up-curved; stamens 10(or 12), in 2 unequal series, bright yellow, filaments suberect or reflexed, shorter ones 1.4–4.2 mm, longer ones (1.9–)3.3–6 mm, anthers oblong, 0.5–2.2 mm; ovary subcylindric or truncate, 6–20 × 1.5–3 mm, apex somewhat broader, glabrous or sparsely to densely hirtellous; nectary disc slightly raised on ovary apex, 2–2.5 mm diam., lobed, glabrous or fringed with long hairs; style (1.9–)2.4–7.3 mm, glabrous or sparsely to densely hirtellous on proximal 1/2, stigma flattened-globose, 0.9–1.2 × 1–2.5 mm, sometimes shallowly or deeply 5-lobed, as long as or exserted beyond anthers. Capsules cylindric, subterete to obscurely 5-angled, straight or curved, 10–40 × 2–4 mm, with thick woody walls, irregularly and tardily dehiscent, pedicel 7–60(–90) mm. Seeds embedded in elongated piece of endocarp, 1–1.5 × 0.9–1.3 mm. 2n = 16.
Discussion
Subspecies 4 (3 in the flora): United States, Mexico, West Indies (Cuba), Central America, South America, Asia (China), Pacific Islands (Galapagos Islands); introduced in Europe (France), elsewhere in the Pacific Islands (New Zealand, Society Islands), Australia.
Ludwigia peploides consists of four subspecies more or less well defined geographically and morphologically, with three present in the flora area: subsp. glabrescens, subsp. montevidensis, and subsp. peploides (P. H. Raven 1963[1964]); these subspecies have ranges that are mostly distinct. Subspecies peploides has a wide distribution in the New World, from the southern United States south to Argentina. Subspecies glabrescens is widespread in eastern United States. Subspecies montevidensis occurs primarily in southern South America and scattered (probably introduced) in the southern United States, Australia, France, and New Zealand. Subspecies peploides and montevidensis occur together locally in California and Louisiana, where subsp. montevidensis is introduced. The ranges of subsp. glabrescens and peploides come together in Texas.
Subspecies stipulacea (Ohwi) P. H. Raven is known from eastern Asia (e China).
Selected References
None.
Lower Taxa
Key
| 1 | Stems usually densely villous, rarely sparsely so; leaf blades not shiny, apices glandular-mucronate; capsules (20–)24–32 mm. | Ludwigia peploides subsp. montevidensis |
| 1 | Stems glabrous or sparely villous; leaf blades shiny, apices usually eglandular-mucronate; capsules 10–40 mm. | > 2 |
| 2 | Principal leaf blades 0.8–4(–8.5) cm; petioles 0.2–2.5 cm; pedicels 10–35 mm; capsules 10–17(–25) mm; seeds 7–14 per locule. | Ludwigia peploides subsp. peploides |
| 2 | Principal leaf blades (2–)4–10 cm; petioles 0.7–6 cm; pedicels 35–90 mm; capsule 25–40 mm; seeds 16–18 per locule. | Ludwigia peploides subsp. glabrescens |