Flora of Usina São José, Igarassu, Pernambuco (Brazil): Lythraceae J. St.-Hil. and Onagraceae Juss

Lythraceae comprises about 30 genera and 600 species widely distributed in tropical and subtropical regions, while Onagraceae comprises 22 genera and about 660 species distributed in temperate and subtropical areas, predominantly in Americas. The aim of this work was to realize the taxonomic study of Lythraceae and Onagraceae species from Usina São José, Igarassu, Pernambuco (Brazil), an Atlantic forest remnant. Fieldworks and visits to herbaria HST, HUEFS, IPA, JPB, PEUFR and UFP were conducted between 2018 and 2019. Three Lythraceae species were recognized: Cuphea carthagenensis (Jacq.) J.F. Macbr., C. flava Spreg. and Rotala ramosior (L.) Koehne, and three Onagraceae species: Ludwigia erecta (L.) H. Hara, L. hyssopifolia (G. Don) Exell and L. octovalvis (Jacq.) P.H. Raven. Rotala ramosior is a new record for Brazil. Morphological descriptions, an identification key, phenological period, geographic distribution, taxonomic notes, photographs and illustrations of diagnostic characters are presented herein. The relevant morphological characters for species identification are phyllotaxy, indumentum of stems, shape and indumentum of leaves, petals color and apex, capsule shape, seeds arrangement and raphe size.


Introduction
Myrtales is comprised in Malvidae clade with nine families, including Lythraceae J. St.-Hil. and Onagraceae Juss. that constitute one of the largest clades within the order (Stevens, 2001 onwards;Graham, 2007). Both families present leaves simple, margin entire and frequently opposite, flowers generally hermaphrodite and actinomorphic (Judd, Campbell, Kellog, Stevens & Donoghue, 2009).
Lythraceae is widely distributed in tropical and subtropical regions, with few records of herbaceous species occurring in temperate regions (Cavalcanti, 2007). The family comprises about 30 genera and 600 species (Graham & Graham, 2014). In Brazil, 11 genera and 216 species are recognized, predominantly distributed in Cerrado and Atlantic Forest areas, where 160 species are endemic. Cuphea P. Browne is the most representative genus with 108 species, where 70 are endemic. According to Flora do Brasil (2020, under construction), seven genera and 57 species can be found in i i i the Northeast region. They occur in several different environments and phytogeographical domains, including swamps, dunes, humid tropical forests but more frequently in Cerrado, arid and rocky fields. Are represented by trees, shrubs, or rarely herbs, with simple leaves, commonly decussed, margins entire; inflorescence a raceme or a cyme; flowers bisexual, diclamide, rarely monoclamide, actinomorphic, rare zygomorphic, floral tube persistent, petals 4-16, dialipetals, curly; fruit capsule (Cavalcanti & Graham, 2002). A family representative popularly known as pomegranate, Punica granatum L., is used as food and medicinal.
Onagraceae comprises about 660 species and 22 genera distributed in temperate and subtropical areas, predominantly in Americas (Wagner, Hoch & Raven, 2007). In Brazil, the family is recorded with 62 species and four genera, occurring mainly in Atlantic Forest areas, where 18 species are endemic. Ludwigia L. is the most representative genus with 45 species known, being 10 endemic. According to Flora do Brasil (2020, under construction), two genera and 18 species can be found in the Northeast region.
Onagraceae representatives can be found mostly in swamp areas, but also associated to high altitudes and coastal regions (Micheli, 1872). They can be herbs or trees, easily recognized by the petals 4 (occasionally 5-7 or 2), often with floral tube, ovary inferior, stamens usually the double of the petals number and positioned in two series, epipetals shorter than episepals and pollen connected by viscin (Munz, 1947;Raven, 1963). The family is widely used as ornamental, because of the beautiful flowers, especially the species of Clarkia L., Fuchsia L. and Oenothera L. (Judd et al., 2009).
The Usina São José is located in Atlantic Forest domain and presents forestry fragments that suffer anthropic actions due to the cane plantations that surround them, resulting in implications for conservation (Trindade, Lins-e-Silva, Silva, Figueira & Schessl, 2008). This study aim to provide the taxonomic treatment of Lythraceae and Onagraceae from Usina São José (USJ), increasing the knowledge about the families in Atlantic Forest in the north of São Francisco River.

Material collect
Fieldworks were conducted in the study area between July 2018 and July 2019, however, we did not find any Lythraceae and Onagraceae individuals. The selected areas for the fieldworks included the areas considered priority according to their extension. Six herbaria were visited: HST, HUEFS, IPA, JPB, PEUFR and UFP (herbarium acronyms follow Thiers, continuously updated), totalizing 24 analyzed specimens of Lythraceae and eight of Onagraceae.

Results and Discussion
In Usina São José we identified two genera, Cuphea and Rotala, and three species of Lythraceae and one genus, Ludwigia, and three species of Onagraceae. Rotala ramosior (L.) Koehne is a new record for Brazil (Flora do Brasil 2020, under construction). Besides that, Cuphea carthagenensis (Jacq.) J.F. Macbr. and C. flava Spreng. were identified in the study area. According with Melo et al. (2011), four species of Lythraceae and none of Onagraceae are listed to USJ. Specimens identified as C. calophylla Cham. & Schltdl., C. campestris Koehne and C. micrantha Kunth in this list, were misidentified and herein updated to C. carthagenensis (Jacq.) J.F. Macbr.
At the study area, C. carthagenensis was collected with flowers and fruits between February and November. According to Graham (2017), this is the most widely distributed species of the genus, occurring from United States to Argentina. In USJ, it was found in the edge of Mata dos Macacos and Mata de Piedade. It can be distinguished from C. flava by the indumentum only on one side of the stems and pedicel (vs. on whole surface), leaves elliptical, base cuneate (vs. leaves ovate, base subcordate) and petals rose to purple (vs. yellow). Spreng., Novi Provent. 14. 1818. (Figure 1eh) Herbs or shrubs, ca. 40 cm tall, stems pubescent, trichomes simple, hyaline, yellowish to purplish. Leaves sessile or short petiolate, petioles 0-0.5 mm long, blade 0.5-1.2 × 0.2-0.5 cm, ovate, base subcordate, pilose on the margin, glabrous or glabrescent on the veins and glabrous on both faces, trichomes simple, hyaline to yellowish. Flowers solitary, pedicel 3-4 mm long, bracteoles ovate, pilose on the margin, inserted at the middle third of the pedicel. Floral tube ca. 8 mm long, green, calyx lobes ca. 1 mm long, apex acute, outer surface pubescent, trichomes simple, hyaline to yellowish, inner surface pilose above stamen insertion and pubescent at the base of the ovary, trichomes simple, hyaline to whitish. Petals yellow, 2 petals ca. 4 × 2 mm, 4 petals ca. 3 × 1 mm, obovate, apex rounded. Stamens 2 shorter, included, 9 longer, included or exserted, vesicles absent. Style ca. 5 mm long, exserted.

Cuphea flava
It was collected at USJ with flowers and fruits in February and July. This species is endemic from Brazil, occurring from Rio Grande do Norte to Rio de Janeiro (Flora do Brasil, 2020 under construction). At the study area was found in the inland of Mata dos Macacos and in the edge of Mata da Zambana. The differences between C. flava and C. carthagenensis were discussed under the comments of that species. Rotala is represented by about 45 species predominantly from Africa and Asia, besides few species from Americas (Cook, 1979). In Usina São José occurs only one species. Herbs, ca. 20 cm tall, stems glabrous. Leaves sessile, blade 0.4-1.6 × 0.1-0.4 cm, narrow-elliptic, base decurrent, apex obtuse, glabrous on both faces. Flowers solitary, sessile or short pedicellate, pedicel 0-0.5 mm long, glabrous, bracteoles 2-3 mm long, linear, glabrous, inserted at the base of the floral tube. Floral tube 2-3 mm long, colour not seen, urceolate, calyx lobes ca. 0.5 mm long, apex cuneate, appendages of size nearly equal to the calyx lobes, glabrous, spur absent, outer and inner surfaces glabrous. Petals white not seen. Stamens 4, each pair is positioned at a different level, included, vesicles absent. Style ca. 0.5 mm long, included. Capsule globose. Seeds ca. 0.5 × 0.5 mm, concavo-convex.
Rotala ramosior was collected with flowers and fruits in September at USJ. This species is distributed in Americas (GBIF, 2019), but according to Flora do Brasil (2020, under construction), it does not occur in Brazil. The genus was considered naturalized, since two species were recorded in São Paulo (Cavalcanti & Graham, 2002). Therefore, we considered this species also naturalized in Brazil, since it was found growing spontaneously in Mata da Zambana, on the edge of sugar cane plantation. Rotala ramosior is distinguished easily from Cuphea species by being completely glabrous, with petals white. Onagraceae Juss.
In Brazil are recorded four genera and in Usina São José occurs one, Ludwigia.
It was collected at USJ with flowers and fruits in January. This species is widely distributed in the Neotropics, occurring from Florida to Brazil (Goldblatt & Raven 1997). At the study area was found on the edge of Mata de Santa Helena. It can be identified by the petals with apex rounded, capsule linear-oblong, 4-angulate and seeds plurisseriate in all regions not embedded in endocarp.    Herbs, stems glabrous. Leaves sessile, blade 1.3-2.8 × 0.35-0.5 cm, lanceolate, base decurrent, apex attenuate, glabrous on both faces. Hypanthium not seen. Sepals 4.5 x 1 mm, lanceolate, glabrous on both faces.
Petals not seen. Style and stigma not seen. Stamens not seen. Nectariferous disk not seen. Capsule 17-20 mm long, linear, slightly enlarged in the superior region, glabrous. Seeds plurisseriate and free in the superior region, unisseriate and embedded in cortical endocarp in the inferior region, raphe narrower than the body of the seed.
It was collected at USJ with flowers and fruits in November. This species is pantropical (Zardini & Raven, 1997). At the study area was found in Chave fragment. It can be distinguished from the other species by the position of the seeds in the capsule, free and plurisseriate in the superior region and embedded in cortical endocarp and unisseriate in the inferior region. Herbs, ca. 60 cm tall, stems glabrescent or pubescent. Leaves short petiolate, petioles ca. 0.5 mm long, blade 5.5-7.1 × 1.6 cm, linear-lanceolate or lanceolate, base acute, apex acute, glabrescent or pubescent. Hypanthium 20-35 mm long. Sepals 10-12 × 4.5-5 mm, ovate, outer face hirsute or pubescent. Petals 12 × 8 mm, obovate, apex emarginate. Style ca. 2 mm long, stigma capitate. Stamens 8. Nectariferous disk convex. Capsule ca. 42 mm long, cylindrical, 8-ribbed, glabrescent or pubescent. Seeds plurisseriate in all regions and not embedded in endocarp, raphe inflated equal in size to the body of the seed.
It was collected at USJ with flowers and fruits in April, August and November. This species is pantropical, occurring predominantly in Americas (Raven, 1963;Grillo & Giuletti, 2004). At the study area was found in Fragmento Chave and in the edge of Mata de Piedade. It can be identified from the other species by the petals with apex emarginate, capsule 8-ribbed, seeds with raphe inflated equal or superior in size to the body of the seed, plurisseriate in all regions and not embedded in endocarp.