Ludwigia leptocarpa (Nutt.) 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 : 15-17

Ludwigia leptocarpa (Nutt.) H.Hara

Figs 5b , 6 l–u, 7a–c

Material examined

BRAZIL – Paraíba • Areia , UFPB; 2 Dec. 2016; fl.; A.M. Rocha 06; HACAM • João Pessoa, riparian vegetation of the Rio do Cabelo , Mangabeira ; 19 Nov. 2010; fl.; L.A. Pereira 45; JPB • João Pessoa, AeroClube ; 18 Nov. 2008; bud and fl.; A.C.C. Almeida 141; JPB • Patos, Assentamento Patativa do Assaré ; 20 Jan. 2012; fl.; C. Torres 144; CSTR • Pirpirituba ; 9 Sep. 2016; fl.; A.M. Rocha 03; HACAM • Poço Dantas ; 11 Oct. 2007; fl.; G.A. Costa et al. 34; JPB • Rio Tinto, Gameleira ; 6 Apr. 1989; fl.; L.P. Felix 3685; EAN • Sapé ; 19 May 2014; fl.; H.O. Machado-Filho 426; PEUFR .

Description

Subshrubs, 1–1.6 m high, erect; branches cylindrical, hirsute. Leaves subsessile; blade 7–12.2 × 2.1– 2.6 cm, with entire margin, membranous, elliptical, with acute apex and decurrent base, with hirsute nervure. Flowers pentamerous (sometimes hexamerous), pedicels ca 7 mm long.; bracteoles 2, near the base of hypanthium, smaller than 1 mm in length; sepals 10–11 × 3.5–4 mm, green, lanceolate, with attenuate apex, external face hirsute; petals 15–16 × 12–13 mm, golden yellow, obovoid, shortunguiculated, with rounded apex; hypanthium ca 2 cm long, 5-locular; style ca 4 mm long, stigma capitate; stamens 10, anthers oblong; convex nectariferous disk with depressed nectaries, densely pilose, surrounding the base of each epipetalous stamens. Capsule 3.5–3.6 × 2.6 cm, cylindrical, internally nondimorphic, hirsute. Seeds ca 1 mm long, ellipsoid, uniseriate, embedded in horseshoe-shaped endocarp from which the seeds are easily detached, raphe non-inflated, with diameter narrower than the body of the seed.

Distribution

The species has a wide distribution in Neotropical region, from southeast USA to Argentina and Africa ( Zardini & Raven 1997). In Brazil, it occurs in almost all phytogeographic domains in North (AC, AM, PA), Northeast (AL, BA, CE, PB, PI, SE), Center-West (DF, GO, MS, MT), Southeast (ES, MG, RJ, SP) and South (PR, RS, SC) Region ( Lima et al. 2013; Vieira 2015).

Habitat and phenology

In Paraíba State, L. leptocarpa may be found on the banks of lakes and in the flooded areas, in the vegetation of Caatinga and Atlantic Rainforest. It is flowering from September to December and fruiting in September.

Conservation status (Paraíba State, Brazil)

The extent of occurrence (EOO) of Ludwigia leptocarpa is 15 683.720 km 2 (within the limit for Vulnerable status under the criterion B1) and its area of occupancy (AOO) is 32 km 2 (within the limit for Endangered status under the criterion B2). It is known from eight specimens representing a total of eight locations, within the threshold for Vulnerable under criterion B, no population has been recorded in a protected area. In the Paraíba State, the species falls under the category Vulnerable (VU), defined according to criterion B1ab(ii,iii).

Note

Ludwigia leptocarpa is characterized by a yellow pentamerous corolla, which is a unique feature within the genus, as all other species of the genus have a tetramerous yellow corolla or a pentamerous white corolla. Uniseriate seeds embedded in horseshoe-shaped endocarp are the most relevant characteristic of L. leptocarpa . The horseshoe-shaped endocarp is a diagnostic feature of Ludwigia sect. Seminuda , a section to which L. leptocarpa belongs ( Zardini & Raven 1992; Wagner et al. 2007).

Figures

Fig. 5. Map showing the geographic distribution of Ludwigia L. species in the Paraíba State, Brazil.

Fig. 6. a–k. Ludwigia hyssopifolia (G.Don) Exell, A.M. Rocha 16. a. Habit. b. Flower. c. Sepal. d. Petal. e. Plain nectariferous disk. f. Epipetalous stamen. g. Episepalous stamen. h. Fruit. i. Transversal cut of the upper section of the fruit. j. Transversal cut of the lower section of the fruit. k. Seed. – l–u. L. leptocarpa (Nutt.) H.Hara, A.M. Rocha 06. l. Habit. m. Bracteoles. n. Flower. o. Sepal. p. Petal. q. Convex nectariferous disk. r. Fruit. s. Transversal cut of the fruit. t. Section of the horseshoe-shape endocarp. u. Seed. Illustrations by R.M.A. de Carvalho.