Synopsis of Rubiaceae from the Iguaçu National Park, Paraná, Brazil

Iguaçu National Park represents the largest fragment of Inland Atlantic Rainforest of Paraná state. The vegetation is predominantly seasonal semideciduous forest, in the areas of Foz do Iguaçu and Capanema and a transition of this with Araucaria forest, in the Céu Azul area. This work aimed to recognize the genera and species of Rubiaceae occurring in the Park, through monthly collections from August 2013 to July 2014, supplemented with sporadic collections from May 2018 to April 2019. Thirty-five species were recorded, belonging to 19 genera. The most representative genera were Palicourea and Psychotria with five species, Galianthe , Manettia , Borreria with three, Geophila and Coccocypselum with two, and the other genera with only one species each. The areas with the major species richness were Foz do Iguaçu, with 24, of which four are exclusive to this area, followed by Céu Azul with 22 species, of which eight are exclusive. Of the 35 species recorded, seven occur in all areas and in both forest formations, seven occur only in the Araucaria forest area, and 20 occur only in the seasonal semideciduous forest. Borreria orientalis is highlighted due to its restricted distribution in Brazil, occurring only in Paraná, and Manettia tweedieana is considered endangered. mensais de agosto de 2013 a julho de 2014, complementadas com coletas esporádicas de maio de 2018 a abril 2019. Foram encontradas 35 espécies, pertencentes a 19 gêneros. Os gêneros mais representativos foram Palicourea e Psychotria com cinco espécies, Galianthe , Manettia , Borreria com três, Geophila e Coccocypselum com duas e os demais gêneros com apenas uma espécie cada. As áreas com maiores riquezas de espécies foram Foz do Iguaçu, com 24, sendo quatro exclusivas desta área, seguidas de Céu Azul com 22 espécies, das quais oito são exclusivas. Das 35 espécies encontradas sete ocorrem em todas as áreas e em ambas as formações florestais, sete ocorrem só na área de Floresta Ombrófila Mista e 20 ocorrem somente na Floresta Estacional Semidecidual. Destacam-se ainda Borreria orientalis por ter uma distribuição restrita no Brasil, apenas no Paraná e Manettia tweedieana por ser considerada “Em Perigo” de extinção.


Introduction
Rubiaceae Juss. is considered the fourth richest botanical family, only behind Orchidaceae, Asteraceae and Leguminosae (Davis et al. 2009). The family has a cosmopolitan distribution, with greater diversity in the tropics, occurring in almost all forest formations (Souza & Lorenzi 2012). It has approximately 650 genera and 13,000 species (Delprete & Jardim 2012) being also the fourth most diverse family in Brazil, with 126 genera and 1,404 species, of which 731 are considered endemic (BFG 2018). Rubiaceae can be easily recognized in the vegetative stage, due to its simple leaves, opposite, rarely verticillate, leaf blade with entire margin, presence of interpetiolar (rare intrapetiolar) stipules, although in some cases they may be extremely small, but visible, rarely absent. When deciduous, they leave a linear scar at petiole height (Campos et al. 1999).
According to Delprete & Jardim (2012), for southern Brazil Rubiaceae has a satisfactory level of taxonomic studies, but this conclusion is based mainly on specimens from Santa Catarina (Delprete et al. 2004(Delprete et al. , 2005. In Paraná, only a floristic study of the arboreous and shrubby species of the Tibagi River basin (Ferreira Junior & Vieira 2015), a review of Manettia Mutis ex L. (Marinero et al. 2012), a Rubiaceae flora of riparian vegetation of a stretch of the upper Paraná River (Pereira 2007), and a floristic study of the Psychotrieae, Coussareeae and Morindeae tribes in the region of Porto Rico, Upper Paraná River (Souza & Souza 1998) have been provided. In the Management Plan of the Iguaçu National Park only four species of Rubiaceae are mentioned, Faramea cyanea Müll. Arg., Manettia sp., Palicourea marcgravii A.St.-Hil., and Psychotria sp. (IBAMA 1999), and this low number is probably due to the predominance of herbaceous or shrubby species in the family, while management plans usually sample tree species.
For the Iguaçu National Park an epiphyte listing (Cervi & Borgo 2007), a study on ferns and lycophytes (Lautert et al. 2015) and tree species surveys (Gris & Temponi 2017;Souza et al. 2017) have been provided. In addition, floras or synopses of representative families of the shrub and herbaceous strata have also been monographed and are currently being published: Orchidaceae (Boff 2016), Acanthaceae, and Verbenaceae (Hammes 2017), Cyperaceae and Poaceae (Jesus 2017), and Bignoniaceae (Hentz Junior 2018). The Rubiaceae, being well represented in species richness and abundance, is an important indicator for taxonomic, ecological, and conservation studies (Delprete & Jardim 2012), which confirms the need for a floristic survey for the family in Iguaçu National Park, contributing to the biodiversity assessment in this important conservation unit of Paraná.

Study area
Due to its favorable soil for agricultural activities, the original vegetation of western region of Paraná state has been extremely devastated over the years, leaving only small portions of original formations (Maack 2012). Iguaçu National Park ( Fig. 1) represents the largest of these fragments, although it corresponds to less than 4% of the original area. The Park is part of the Atlantic Forest biome, represented by the Submontane Semideciduous Seasonal Forests (SSF) and Araucaria Forest (AF) (IBAMA 1999;Roderjan et al. 2002;IBGE 2012), with a total area of 185,262.5 hectares and a perimeter of 420 km, at the coordinates 25º05' to 25º41' South and 53º40' to 54º38' West (IBAMA 1999). It is located in the subtropical climate region (Cfa) and the summers are hot and have a higher concentration of rainfall, but there is no defined dry season and the frequency of frost is low (IAPAR 2010).
For this study the Park was divided into three areas ( Fig. 1): the Céu Azul Area, covering the trails located in the northern portion of the Park, the Capanema Area to the south and the Foz do Iguaçu Area in the southwest region. In the Area 1 (Céu Azul) there are the following trails: Fazenda Rio Butu, Nascentes do Jumelo, Araucárias, Cachoeira rio Azul, Manoel Gomes and Jacutinga ( Fig. 1a-f). The trails are predominantly under Montane AF with transition to Submontane SSF, at altitudes ranging from 400 to 700 meters. In the Area 2 (Capanema) the trails were Iguaçu River Banks on the Brazilian side, Cachoeira Rio Silva-Jardim, and Ilha do Sol (Fig. 1). The predominant forest formation is Submontane SSF at altitudes of 150 to 250 meters. In order to have access to the trails, a motor boat was used, traveling along the Iguaçu River. Rubiaceae species seen along the river banks were also collected. In the Area 3 (Foz do Iguaçu) the trails were Poço Preto, Represa São João, Antiga Usina, Escola Parque, Macuco Safari, Bananeiras, Cataratas, and Hidrante ( Fig. 1j-q). Its vegetation is predominantly Submontane SSF, with altitudes ranging between 100 and 270 meters.

Data collection and analysis
Field work was made monthly to several trails in Iguaçu National Park ( Fig. 1) between August 2013 and July 2014. Complementary collections were performed sporadically between May 2018 and April 2019, using the walking method described by Filgueiras et al. (1994). After being collected, photographed, analyzed and herborized using standard techniques (Bridson & Forman 2004), the specimens were identified through specific literature (Delprete et al. 2004;2005;Jung-Mendaçolli 2007) and by comparison with herbarium collections from other institutions: CTES, EVB, FUEL, HUEM, MBM, and UPCB (Thiers, continuously updated). And the specimens were deposited in the UNOP herbarium and their duplicates are in CTES, EVB, HCF, and MBM.
Morphological studies of vegetative and reproductive characteristics were made with a stereomicroscope. These characteristics were used for the elaboration of identification keys and illustrations. The morphological terms follow Radford et al. (1974), Stearn (1992) and the spellings of the scientific names and their authors were verified in The International Plant Names Index (IPNI 2019) and BFG (2018). Data on flowering, fruiting, and geographic distribution of the species were obtained from the specimens collected and from those deposited in the herbaria cited above, as well as in specific literature (Delprete et al. 2004(Delprete et al. , 2005.
It is distributed in Central and South America and as an introduced species into Africa, Asia and Australia. In Brazil, occurs in almost the entire country except Rio Grande do Sul and in almost all vegetation types (Cabral et al. 2011;BFG 2018). In Iguaçu National Park, it was found only at municipality of Santa Tereza do Oeste, in the Céu Azul area (AF).
The species can be observed flowering and fruiting through the year (Cabral et al. 2011). In the Park it was found in both flower and fruit in May. This species is characterized by having inflorescences with numerous axillar glomeruli, each one with two bracts, yellowish leaves when dry, bifid stigma, and corolla lobes internally pilose.  It is distributed in Northern Argentina, eastern Paraguay, and southern Brazil. In Brazil it only occurs in the state of Paraná (Cabral et al. 2012). In the Park it was found only in the "Foz do Iguaçu" area.
In the Park the species was collected with flowers and fruits between August and December.
The species is characterized by only one terminal glomerulus and a subterminal one, it has four foliaceous bracts that are three times longer than the inflorescence, and ruminate seeds.  It is distributed in Northeast Argentina, Paraguay, and Brazil, where it is widely distributed in several vegetation types (BFG 2018). In the Park the species was found in all areas.
Flowers and fruits all year long (Cabral et al. 2011). In the Park the species was found flowering and fruiting in February and March.
The species is characterized as being a scandent subshrub (Silveira 2010) with a tubular margin of the stipular sheath, extending beyond the base of the leaf blade. As B. latifolia, when dry its leaves are also yellowish.  It is distributed throughout the River Plate Basin, Paraguay, Argentina, and Uruguay. In Brazil, it occurs in the southern states, as well as São Paulo, Mato Grosso, and Mato Grosso do Sul (Delprete et al. 2004;BFG 2018). In the Park the species was found only in the Foz do Iguaçu Area.

Cephalanthus
According to Delprete et al. (2004), this species flowers between November and December. The species occurs in almost all states in Brazil, except in the northern region, and it extends to Argentina throughout the River Plate Basin (Delprete et al. 2004;BFG 2018). In the Park the species was found in the areas of Foz do Iguaçu and Céu Azul.
The flowering of this species begins in October according Delprete et al. (2004), although in the Park it was found flowering between December and February, and fruiting in February through March.
The species differs from remaining species of Chomelia inhabiting South Brazil by having leaves with tertiary veins obscure (BFG 2018) and domatia in crypt (Romero et al. 2015  The species is distributed in Guyana, Peru, Paraguay, and Brazil, where it occurs in states (Delprete et al. 2004;BFG 2018). In the Park, it occurs only in the Céu Azul area (AF).
Flowers from October to February (Delprete et al. 2004). In the Park the species was found flowering from December through February. This species is characterized by the absence of indumentum on vegetative parts and by pedunculate inflorescences.  Flowers and fruits through the year (Cabral & Salas 2007). In the Park, it was found fruiting in June and July. This species is characterized by its dense hirsute indumentum, with long erect trichomes and sessile inflorescences (Costa & Mamede 2002).  This species occurs in Argentina, Paraguay, and Brazil, where it occurs in all regions (Delprete et al. 2004;BFG 2018). In the Park, it was found in municipality of Santa Tereza do Oeste in the area of Céu Azul (AF).

Cordiera
Flowers from November to March (Delprete et al. 2004). In the Park, the species was found flowering in December and January. This species is characterized by its subsessile to shortly petiolate leaves, with elliptical, oblong to lanceolate blades, usually chartaceous to subcoriaceous, and leaf domatia in crypt.  (2007); Ferreira Junior & Vieira (2015). It is distributed throughout Argentina, Paraguay, and Brazil, where it has a wide distribution, except in the northern region (Gomes 2003). In the Park, it was found in the Foz do Iguaçu and Capanema areas.
The species has marked flowering in October and November, and its fruits ripen in May and June (Gomes 2003). In the Park, it was found flowering in October and with unripe fruits in February.
This species is characterized by its unbranched inflorescences axes and markedly compressed fruits (Gomes 2003  It is distributed in South America in Brazil, Argentina, and Paraguay (Bacigalupo & Cabral 1999). In Brazil, it occurs in the Central-west, Southeast, South and in the state of Bahia in the Northeast region (BFG 2018), and in the Park it was found in the areas of Foz do Iguaçu and Capanema.
Flowering from October to March (Delprete et al. 2004). In the Park it was found flowering in October and February. This species is characterized by the corolla rising over the foliage close to the ground (Bacigalupo & Cabral 1999;Jung-Mendaçolli 2007), style bifid with stigmatic spreading branches, corolla lobes internally pilose, and by presenting fruits hidden by the stipular sheath, indehiscent. The species is distributed in South America in Brazil, Argentina, and Paraguay. In Brazil, it occurs in the states of Sergipe and Bahia, throughout southeastern region unto the state of Paraná (Gomes 2003;BFG 2018). In the Park, the was found only in the Foz do Iguaçu area.
Flowers in September and October, and fruits in February (Gomes 2003). In the Park, the was found flowering and fruiting from June to February. This species is characterized by the translucent dots of the leaves, which have a sharp-cuneate base and abruptly cuspidate apex and by its blue flowers (Gomes 2003   The species is distributed in South America, in Brazil, Paraguay, Uruguay and Argentina (Cabral & Bacigalupo 1997). In Brazil it is present throughout the South and Southeast, in the Central-west in Mato Grosso do Sul and in the Northeast in Bahia (BFG 2018); in the Park the was found in the Foz do Iguaçu and Capanema areas.
Flowers and fruits through the year, with predominance from December to March (Delprete et al. 2004). In the Park it was found flowering and fruiting in May, and from October to December. This species is characterized by its subshrubby habit, abundant branching and small leaves compared to other species of Galianthe studied and with only the primary vein visible. In addition, it has thyrsoid, monochasial and dichasial inflorescences, short pedunculate, and fruits dehiscing into two indehiscent mericarps. The species is distributed in South America, in Paraguay and northeastern Argentina, besides Brazil (Cabral & Bacigalupo 1997), where it occurs in the South and Southeast of the country (BFG 2018). In the Park it was found in all areas.
Flowers and fruits from spring to early fall (Cabral & Bacigalupo 1997). In the Park, the was found flowering and fruiting in July and from October to March. This species is characterized by its stoloniferous habit, radicant at the nodes, and fruits splitting into two indehiscent mericarps (Cabral & Bacigalupo 1997). The species is distributed in South America, in Brazil, Argentina, Bolivia, Paraguay, and Uruguay. In Brazil it occurs in the Central-west, Southeast, and South regions of the country (Cabral 2009); in the Park it was found in all areas.
Flowers from November to February, and fruits from March to August (Cabral 2009). In the Park, the was found flowering and fruiting from February to December. This species is characterized by abundant branching and by the lax, thyrsoid inflorescences.  This species has a very wide distribution, from the Caribbean islands, Central America, and all of South America (Delprete et al. 2004). In Brazil, it occurs in all regions except the North (BFG 2018); in the Park it was found only in the Céu Azul area (AF).
Reproduction may occur through all year (Delprete et al. 2004); in the Park, the was found fruiting in June. Dempster (1990) recognized 4 subspecies, of which in ParNa inhabits G. subsp. hypocarpium. Differs from the others by its flowers up to four by each node and sessile leaves. This taxon differs from the other species of ParNa Iguaçu by having stipules of the same shape and size as the leaves and orange drupaceous fruits.   The species is distributed in Mexico by Central and South America, occurring until Bolivia, and Paraguay (Delprete et al. 2005). In Brazil, it occurs in the South region (BFG 2018), and in the Park it was found in all areas.
Flowers and fruits in December, February and July (Delprete et al. 2005). In the park, the was found flowering from January to March, and fruiting all year long. This species is characterized by being a prostrate herb, with cordiform leaves and dark purple fruits.  The species is distributed from Central America to southern Argentina (Williams 1973). In Brazil it occurs in states of all regions (BFG 2018), and in the Park it was found in all areas.

Geophila repens
Flowers in the summer (Delprete et al. 2005). In the Park, the was found flowering in December and January and fruiting all year long. This species is characterized by being a prostrate herb, with cordiform to reniform leaves having a truncate base and by its orange fruits.  This species is distributed throughout Bolivia, Argentina, Uruguay, and Brazil, where it occurs from the states of Minas Gerais, and Bahia unto the state of Rio Grande do Sul. (Delprete et al. 2005;BFG 2018). In the Park it was collected in Matelândia in the area of Capanema.
Flowers from December to April (Delprete et al. 2005). In the Park the was found flowering in October.
This species differs from the remaining species of Guettarda inhabiting in Paraná state by having umbelliform axillary inflorescence or in multiflorous dichotomous cymes, flowers and fruits pilose, and 3-locular ovary (Delprete et al. 2005).  The species is distributed from Mexico, Central, and South America to northern Argentina (Delprete et al. 2005). In Brazil it occurs in almost all states (BFG 2018), and in the Park it was found in all areas.

Hamelia
Flowers from December to February (Delprete et al. 2005); in the Park, the was found flowering and fruiting almost all year long. This species is characterized by having generally 3-verticilatte leaves, and showy, puberulous, and reddish-orange flowers.
Flowers from May to December (Delprete et al. 2005), and in the Park, the was found flowering in October.
This species is easily recognized by its leaves with very dense secondary venation (30-60 veins per side) (Delprete et al. 2005;Jung-Mendaçolli 2007) and with a stipular sheath tubular, apically 1-fimbriate, prolonged above the corresponding pair of leaves.  The species is distributed from Peru to Uruguay (Macias 1998). In Brazil it is widely distributed in all regions except the North, where it occurs only in Acre (BFG 2018); in the Park it was found in all areas.

Key to species of Manettia in Iguaçu National Park
Flowers and fruits throughout the year but has flowering peaks from October to January, and fruiting from June to August (Macias 1998). In the Park, the was found flowering from October to May, and fruiting in March.
This species has a great variability in leaf size and shape, ranging from elliptical to ovate blades, from obtuse to cordate at base, however can be distinguish by its bracts usually cordate and sessile, corolla tubular-claviform, and floral button rounded or obtuse at the apex.  The species is distributed in South America, in Brazil, Argentina, Paraguay, and Uruguay (Macias 1998). In Brazil it is present throughout the South region, in the Southeast only in São Paulo state and in the Central-west in Mato Grosso do Sul state (BFG 2018). In the Park it was found in all areas.

Manettia paraguariensis
Flowers and fruits all year long (Macias 1998). In the Park, the was also found flowering and fruiting almost all year long. This species is characterized by presenting a thick corolla that is bicolorous, with a yellow apex and red tube. The corolla also has an inflated base and apex rounded in button state, which represent the main differences with its closest relative M. luteorubra (Vell.) Benth. (Macias 1998;Marinero et al. 2012). The species occurs in Brazil, and in Paraguay and Argentina in places that border Paraná (Macias 1998). In Brazil is mainly distributed in the state of Paraná, occurring in São Paulo, and Santa Catarina. In the Park, the was found in all areas. It is considered endangered by Marinero et al. (2012).

Manettia tweedieana
Flowers and fruits all year (Marinero et al. 2012). In the Park, the was found flowering in April, June and August and fruiting in June through August.
This species is characterized by thin and shortly winged stems, blades narrowly elliptic with long acuminate apex, and inflorescences 1-florous.  This species is endemic to Brazil and distributed in the states of Paraná, and Santa Catarina (BFG 2018). In the Park it was collected in the Céu Azul area (AF).

Manettia
Flowers from November to February with fruits in the fall (Delprete et al. 2005), however, in the Park it was only found flowering in October.
This species is morphologically similar to Palicourea marcgravii which also occurs in the Park and has a pubescent yellowish corolla, with a lilac or purple apex, while P. australis has a densely pubescent corolla with stout trichomes externally, scurfy surface. In South America, the species is distributed in Brazil, and Paraguay (Delprete et al. 2005). In Brazil, occurs in the South and Southeast of the country (BFG 2018); in the Park it was found in all areas.

Palicourea brevicollis
Flowers from October to February and fruits from March to July (Delprete et al. 2005). In the Park, the was found flowering and fruiting from February to May and from August to December, in January only fruits were found. This species is characterized by hardened bilobate stipules, narrowly pyramidal inflorescence and nigrescent fruits when ripe. The species is widely distributed throughout the eastern Caribbean islands, Colombia to Paraguay, and Argentina (Jung-Mendaçolli 2007). In Brazil it is present in the Central-west, Southeast and Northern regions and in the state of Paraná in the South region (BFG 2018). In the Park, the was found in Foz do Iguaçu and Capanema.

Palicourea croceoides
Flowers from November to February and fruits in February, May, and June. (Jung-Mendaçolli 2007). In the Park, the was found flowering in December and fruiting from December to March. This species is characterized by inflorescence in paniculate lax, flowers glabrous, its membranous corolla that is completely yellow.   Flowers in March and April and fruits from April to June in Paraná (Delprete et al. 2005). In the Park, the was found fruiting in July and September. This species is characterized by having much longer inflorescences than others of the same genus that occur in the Park, being narrowly pyramidal, almost cylindrical. A.St.-Hil., Hist. Pl. Remarq. Bresil, 231, t. 22 1824. Figs. 6g;7e Supplementary Bibliography: Jung-Mendaçolli (2007); Ferreira Junior & Vieira (2015).
Flowers through all year and fruits from January to July (Taylor 2007). In the Park, the was found flowering in November and flowering and fruiting in December, and March.
This species is similar to Palicourea australis, but it differs by having the corolla externally pubescent, without stout trichomes, and yellowish on base and purple or lilac on apex.
The species is distributed in Paraguay and Brazil, where it occurs in the states of São Paulo, Paraná and Mato Grosso do Sul (Jung-Mendaçolli 2007;BFG 2018). In the Park, the was found in Foz do Iguaçu and Capanema.
Flowers in November and fruits from March to October (Jung-Mendaçolli 2007). In the Park, the was found flowering in December, February and March and with fruits from February to April and from July to September. This species is characterized by its small, entire stipules; lax, cymose inflorescences and red fruits. Jacq., Enum. Syst. Pl. 16. 1760. Figs. 7g-i;8a Supplementary Bibliography: Jung-Mendaçolli (2007); Ferreira Junior & Vieira (2015). The species is widely distributed from Costa Rica to Argentina and Paraguay (Delprete et al. 2005). In Brazil, the species has a distribution throughout the country (BFG 2018), and in the Park, the was found in all areas.

Psychotria carthagenensis
Flowers and fruits all year long (Jung-Mendaçolli 2007). In the Park it was found flowering from November to March and fruiting throughout the year.
This species is easily distinguish from remaining species of Psychotria inhabiting Paraná state, by having the leaf domatia in pocket (Romero et al. 2015), ovate or obovate stipules, entire, apex obtuse, early caducous, and lax inflorescences. The species is endemic to Brazil, occurring in the states of Santa Catarina, and Paraná (BFG 2018). In the Park, the was found in Serranópolis do Iguaçu in the Capanema area.

Psychotria fractistipula
According to Delprete et al. (2005) this species flowers during the summer; in the Park, the was found with flowers in October.
This species and Psychotria carthagenensis share the early caducous stipules, entire, ovate or obovate, and leaf domatia in pocket, characters that allow to differentiate them from remaining species of the genus in Paraná state. The only differences are the obtuse apex of the stipule and the congested partial inflorescences. The taxonomic status of P. fractistipula must be evaluated in depth including micromorphology, pollinic, ecologic and molecular analysis. The species is distributed the Southeast of Brazil until Argentina (Jung-Mendaçolli 2007). In Brazil, it occurs in the South, Southeast and in some Northeast states (BFG 2018); in the Park, the was found in all areas.
Flowers from August to January and fruits from March to August (Jung-Mendaçolli 2007). In the Park, the was found flowering in March, May, June, and from August to December, and fruiting in January, March, May, June, July, October, and December.
This species is characterized by narrow leaves, white corolla with inner apex of the tube yellow and blue fruits with longitudinal ridges.  The species is distributed in South America in Brazil, and Argentina (Delprete et al. 2005) In Brazil, it occurs in the South and Southeast of the country (BFG 2018); in the Park, the was found in the Céu Azul area.

Psychotria suterella
It flowers practically all year and fruits from January to April (Delprete et al. 2005). In the Park, the was found flowering in January and February, fruiting in May, June, August, and December. This species is characterized by its dark blue fruit with large, persistent green calyx.  The species is widely distributed throughout North America, the Caribbean islands, all South America and as an introduced species into Africa, and Asia. (Lewis & Oliver 1974;Delprete et al. 2005). In Brazil, it occurs in states of all regions of the country (BFG 2018) and in the Park, the was found in Foz do Iguaçu and at Santa Tereza do Oeste in the Céu Azul area.

Richardia
Flowers and fruits practically all year in warmer regions and in spring and summer in temperate zones (Lewis 1974). In the Park, the was found flowering in February, April, May and from August to December. This species is characterized by its prostrate, herbaceous habit, glomeruliform and terminal inflorescence, usually 6-lobed corolla, and by schizocarpic fruit with three mericarps.  Distribution is difficult to assess because its identification has been confused over the years with Spermacoce glabra Michx. (Bacigalupo 1972). According to Nuñez et al. (Florentin et al. 2020), The species occurs only in South America: Paraguay, Bolivia, Peru, Argentina, Uruguay, and Brazil. In this country, it occurs in the states of the South, Southeast, Central-west and Bahia (BFG 2018); in the Park, the was found in Capanema.
In the Park, the was found flowering and fruiting in March and April on riverbanks.
This species is characterized by being a glabrous plant, numerous pseudoaxillary glomeruli (unilateral position), very small flowers, stamens and stigma included, fruits indehiscent or tardily dehiscent at the apex, seed obovate, 1.5-2.5 × 0.8-1.45 mm; plano-convex in cross section; ventral side with a wide, shallow groove,.
All species recorded in the Iguaçu National Park are native to Brazil, only Palicourea australis and Psychotria fractistipula are considered endemic to south region of the country (BFG 2018). Most of the species found are widely distributed and some of the more restricted ones occur in other countries, since the Park is located close to other South American countries and borders Argentina.
The area with the highest species richness was Foz do Iguaçu, with 13 genera and 24 species, with four exclusive to this area. In the Céu Azul area, there are 22 species of which eight are exclusive, distributed in 13 genera and in Capanema 11 genera and 21 species were found (Tab. 1). Some species are widely distributed along the Park's trails, seven occur in all areas and in both forest formations, while 20 species occur only in SSF and seven species occur only in AF (Tab. 1).
Palicourea and Psychotria were the genera that presented the highest species richness in the study areas, with five species each. The species of these two genera together represent 28.5% of the collected taxa. These data contradict the results of other studies in the Atlantic Forest, where the genus Psychotria is represented with, at least, twice of species richness than Palicourea (Pereira et al. 2006;Pereira & Kinoshita 2013). The results of the authors cited are justified since Psychotria is the largest genus of Rubiaceae, with 1,834 species (Davis et al. 2009) and one of the ten largest in Brazil, with 251 species (BFG 2015).
Palicourea is relatively small in comparison, having only 74 species in Brazil (BFG 2018). Also, many neotropical species of Psychotria are being transferred to Palicourea, as was the case of Palicourea brevicollis (Taylor & Hollowell 2016). These tranfers are following the results of recent phylogenetic analyses (e.g., Razafimandimbison et al. 2014) that showed that many species of Psychotria subg. Heteropsychotria Aubl. belong to Palicourea.
The genera Borreria, Galianthe and Manettia were also found to comprise a significant number of species (3), each representing 8.5% of the species found. Coccocypselum and Geophila presented two species each, while the other 12 genera were represented by only one species each.
Of the 35 species that occur in the Park, we highlight two species concerning their conservation status or restricted distribution: Manettia tweedieana, distributed mainly in Paraná, São Paulo and Santa Catarina, and is considered almost threatened (BFG 2018) and locally endangered by Marinero et al. (2012) to Paraná state; and Borreria orientalis which is distributed in Brazil only in the state of Paraná (Cabral et al. 2012;BFG 2018).