Ludwigia helminthorrhiza (Mart.) H.Hara

Rocha, Amanda Macêdo & Melo, José Iranildo Miranda de, 2020, Diversity and distribution of Ludwigia (Onagraceae) in Paraíba State, Northeastern Brazil, European Journal of Taxonomy 639, pp. 1-24 : 12-13

publication ID

https://doi.org/ 10.5852/ejt.2020.639

DOI

https://doi.org/10.5281/zenodo.3794491

persistent identifier

https://treatment.plazi.org/id/B073879A-D14E-FF97-B708-FCD56B6AFB6B

treatment provided by

Valdenar

scientific name

Ludwigia helminthorrhiza (Mart.) H.Hara
status

 

Ludwigia helminthorrhiza (Mart.) H.Hara

Figs 3 View Fig k–r, 4d–e, 5a

Material examined

BRAZIL – Paraíba • Alagoinha, Estação Experimental ; 22 Sep. 1942; fl.; Lauro Xavier s.n.; JPB [958] Araçagi, bank of the Açude Araçagi ; 17 Mar. 2014; fr.; H.O. Machado-Filho 249; CSTR Areia, Mata do Pau Ferro, near Açude Vaca Brava; 6 Oct. 1999; fl.; M.R. Barbosa 1864; JPB Caldas Brandão, Cajá , temporary lake; 1 Nov. 2017; bud, fl. and fr.; A.M. Rocha & E.M. Rodrigues 27; HACAM Gurinhém ; 23 Nov. 2015; I.C. Silva 10; IPA Itaporanga, Fazenda Cafula ; 24 Apr. 2010; M.K. Gomes 02; CSTR João Pessoa, bank of the river Jaguaribe, Bairro Castelo Branco ; 6 Jun. 2000; fl.; M. Costa- Santos & F.M. Barbosa 21; JPB Monte Horebe, dam near the road to the municipality of Serra Grande; 24 Sep. 2014; fl. and fr.; J.L. Costa-Lima et al. 1873; RB Nazarezinho, Rio Piranhas ; 12 Oct. 2007; fl.; P.C. Gadelha-Neto 1901; JPB Olho D’água ; 22 Sep. 2015; T.A. Lycarião 34; IPA Patos, Açude Jatobá ; 10 Jul. 1997; R.L. Leite 23; JPB Pombal , Sítio Maniçoba II; 28 Jul. 2011; fl.; P. D’Angelis et al. 101; CSTR Remígio ; 5 Oct. 2015; fl.; T.A. Lycarião 72; IPA Santa Cruz, Fazenda Catolé ; 30 Jul. 1983; M.A. Sousa 1301; JPB Santa Rita ; Jan. 1993; M.F. Agra 1917; JPB São Bento, stream of Rio Piranhas ; s.d.; R. Medeiros et al. 06; CSTR São José de Piranhas, Reservoir Cuncas ; 10 Jul. 2015; fl.; E. Araújo 45; RB Sapé, Açude Salvador ; 10 Jun. 2014; fl.; H.O. Machado-Filho 548; CSTR Sousa , Vale dos Dinossauros; 10 Oct. 2007; P.C. Gadelha-Neto 1864; JPB .

Description

Herbs exclusively aquatic, decumbent; branches angular, floating, glabrous and hirsute, with white spongy pneumatophores emerging from each branch knot. Leaves petiolate; petiole 1.2–3.0 cm long; blade 4.4–5.7 × 3.2–4.5 cm, with entire margin, membranous, orbicular, with rounded apex and decurrent base, sharply narrow at the petiole, glabrous to sparsely strigose. Flowers pentamerous, pedicellate; pedicels ca 8.5 cm long; bracteoles not visible; sepals 6–8 × 1.5–2 mm, green, lanceolate, with acute apex, external face sparsely hirsute; petals 1.3–1.6 × 1–1.1 cm, white, with basal yellow spot, obovate, unguiculated, with rounded apex; hypanthium 9–12 mm long, 5-locular; style 4.5–5 mm long, stigma capitate; stamens 10, anthers oblong; plain nectariferous disk with depressed nectaries, pilose, surrounding the base of each epipetalous stamens. Capsule 21–27 × 3–4 mm, subcylindrical, 10-ribbed, gradually tapering at the base, not internally dimorphic, pubescent. Seeds ca 1.5 mm long, obovoid, uniseriate, firmly embedded in woody coherent endocarp, raphe non-inflated, with diameter narrower than the body of the seed.

Distribution

Ludwigia helminthorrhiza is distributed in Central America, Argentina, Mexico, Paraguay, Peru and Venezuela; Africa and Madagascar ( Campos 2010). In Brazil, it is restricted to the states of Bahia, Ceará, Pará, Paraíba and Mato Grosso do Sul, associated to phytogeographic domains of the Amazon, Caatinga and Pantanal (Vieira 2015; Torres et al. 2016).

Habitat and phenology

In the Paraíba State, it was collected in dams, temporary lakes, streams and rivers, linked to three mesoregions: Sertão, Agreste and Mata, associated with the Caatinga or Atlantic Rainforest. It produced flowers all the year round and fruits between June and July and between October and November.

Conservation status (Paraíba State, Brazil) The extent of occurrence (EOO) of Ludwigia helminthorrhiza in the Paraíba State is 23 582.060 km 2,

close to the upper limit for Vulnerable status under the criterion B1. Ludwigia helminthorrhiza has an area of occupancy (AOO) of 100 km 2 which could qualify the species for the Endangered status under the criterion B2. However, L. helminthorrhiza is present at more than 5 locations and no evidence of threats or decline was observed. Ludwigia helminthorrhiza is assessed as Near Threatened (NT) in the Paraíba State.

Note

The species differs from other species of the genus in the studied area by its exclusively aquatic habit. Furthermore, it has spongy pneumatophore roots, orbicular leaves, white corolla with a yellow spot at the base and capsules with uniseriate seeds firmly embedded in woody coherent endocarp. Ludwigia helminthorrhiza belongs to Ludwigia sect. Jussiaea (= former section Oligospermum (Micheli) H.Hara ), characterized by seeds strongly embedded in a portion of the woody endocarp ( Zardini & Raven 1992).

Kingdom

Animalia

Phylum

Tracheophyta

Class

Magnoliopsida

Order

Myrtales

Family

Onagraceae

Genus

Ludwigia

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