Ludwigia nervosa H. Hara
Creators: name: Rocha, Amanda Macêdo
name: Melo, José Iranildo Miranda de
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Onagraceae
Ludwigia
Ludwigia nervosa

description: Ludwigia nervosa (Poir.) H.Hara
Figs 5b, 8 h–n
Material examined
Material from Paraíba State
BRAZIL – Paraíba • Mataraca, between Camaratuba and the border with Rio Grande do Norte; 8 Feb. 1968; fl.; A. Lima 68-5312; IPA • Rio Tinto, Mata do Maracujá, Sema III; 23 May 1990; bud and fl.; L.P. Félix et al. 3023; EAN.
Additional material examined
BRAZIL – Bahia • Belmonte, Barrolândia, Estação Experimental “Gregorio Bondar” CEPLAC; 13 May 1993; fl. and fr.; W. Thomas et al. s.n.; NY[9907].
Description
Shrubs, 2.5–3.5 m high, erect; branches cylindrical, glabrous to pilose. Leaves subsessile; blade 4.9– 5.3 × 0.9–1 cm, with entire margin, chartaceous, lanceolate to oblong-lanceolate, with acute apex and acute to obtuse base, glabrous, with pubescent nervure. Flowers tetramerous, pedicellate; pedicels ca 1 cm long; bracteoles not visible; sepals 8–12 × 4 mm, green, lanceolate, with attenuate apex, external face sparsely pubescent; petals ca 14 × 12 mm, pale yellow, orbicular to obovoid, with rounded apex; hypanthium ca 1 cm long, 4-locular; style ca 2 mm long, stigma globose; stamens 8, anthers linear; high nectariferous disk, ca 2 mm high, with depressed nectaries, densely pilose, surrounding the base of each epipetalous stamens. Capsule ca 13 × 5 mm, obconic, 4-angled, internally non-dimorphic, hirsute to glabrous. Seeds 1–1.5 mm long, oblongoid, transversally striated, pluriseriate, not embedded in endocarp, raphe non-inflated, narrower than the body of the seed.
Distribution
Ludwigia nervosa is distributed from South Mexico to Bolivia and Paraguay (Zardini & Raven 1997). In Brazil, it is distributed in the North (AM, AP, PA, RO, RR, TO), Northeast (BA, MA, PE, PI), Center-West (DF, GO, MS, MG), Southeast (ES, MG, RJ, SP) and South (PR) Region, in the phytogeographic domains of the Amazon, Atlantic Rainforest, Savanna (Cerrado), Caatinga and Pantanal (Vieira 2015).
Habitat and phenology
In the studied area, L. nervosa occurs only in the mesoregion Mata, in swampy environments, associated with Atlantic Rainforest vegetation. Flowers occur in February and May.
Conservation status (Paraíba State, Brazil) The extent of occurrence (EOO) of Ludwigia nervosa is 0 km2 and its area of occupancy (AOO) is
8 km 2. According to the IUCN criteria, the species is assessed as Critically Endangered (CR) under criterion B1ab(i,ii,iii)+2ab(i,ii,iii). Ludwigia nervosa is only known from 2 specimens in Paraíba State, one of which was collected almost 50 years ago, and the second 30 years ago. The biome with which it is associated in Paraíba State is frequently degraded by the expansion of sugarcane monocultures, posing a potential threat to the species and possibly causing a continuous decline of its population.
Note
Ludwigia nervosa differs from other Ludwigia species in the studied area by its chartaceous leaves, high nectariferous disk and obconic tetrangular capsule with pluriseriate seeds not embedded in endocarp. Seed characteristics were retrieved from Zardini & Raven (1997).
description: Published as part of Rocha, Amanda Macêdo & Melo, José Iranildo Miranda de, 2020, Diversity and distribution of Ludwigia (Onagraceae) in Paraíba State, Northeastern Brazil, pp. 1-24 in European Journal of Taxonomy 639 on pages 17-18, DOI: 10.5852/ejt.2020.639, http://zenodo.org/record/3786601