Synopsis of Dorstenia ( Moraceae ) in Rio Grande do Sul , Southern Brazil

A taxonomic synopsis of Dorstenia (Moraceae) in Rio Grande do Sul (RS), Southern Brazil, is presented. Three species were recorded: D. brasiliensis, D. carautae, a new record for the state of RS, and D. tenuis. All species are described and illustrated through detailed photos of living specimens. A taxonomic key to separate the species, as well as details on distribution, overall phenology, habitat, conservation status and ecology are presented.


INTRODUCTION
Dorstenia Linnaeus is the second largest genus within Moraceae Gaudichaud and differs from the other genera as per its herbaceous habit, inflorescence of the coenanthium type and by the presence of a rhizome.The coenanthium is composed of a well developed and fleshy receptacle, on which the flowers are inserted; it is open and presents a varied format.The genus is currently inserted within the tribe Dorstenieae Dumort.and has a pantropical distribution.As a whole, this group comprises about 105 species (Carauta 1978, Berg and Hijman 1999, Berg 2001).Brazil holds about 37 species, 31 of them being endemic (Romaniuc-Neto et al. 2014).Traditionally (Berg 2001, Berg andHijman 1999), characteristics of growth habit have been used to set apart the nine sections currently accepted for the genus.A preliminary phylogenetic study (Misiewicz and Zerega 2012) based on molecular characters has suggested that the sections proposed by Berg and Hijman (1999) are not monophyletic.However, this work (Misiewicz and Zerega 2012) presents a restricted and incomplete (ex: several of the type-species of the sections weren't sampled) sampling, making thus premature the rejection of the sections as currently accepted.The sections Lecanium Fischer and Meyer, Dorstenia Fischer and Meyer, and Emygdioa Carauta (as delimitated by Berg and Hijman 1999) are exclusively Neotropical.Section Lecanium comprises shrubby to herbaceous species, with spaced, mostly shortly petiolate leaves.All members of this group are components of the undergrowth and understory of rainforests.Section Dorstenia comprises subcaulescent to caulescent species with long-petioled, large leaves, often bearing lobed to divided leaf blades.Members of this group mostly grow in rainforests, with a few species dwelling in dryer conditions (Berg and Hijman 1999).Section Emygdioa comprises species with relatively small, long-petioled leaves and stems  Berg (2001) proposed two large South-American distribution areas for Dorstenia species: the Southeast Dominion, defined by the distribution of Dorstenia brasiliensis Lamarck, and the Northeastern Dominion, defined by the distribution Dorstenia contrajerva Linnaeus.Southern Brazil and neighboring countries like Uruguay, Paraguay and Argentina represent the distributional limit of the genus in the subtropical region.
In Brazil, the species are widely distributed among its biomes (Amazon Forest, Cerrado, Mata Atlântica, Caatinga, Pantanal and Pampa), but most taxa dwell under tropical conditions (Carauta 1978, Berg 2001).Indeed, Tropical Forest biomes have been considered as important biodiversity hotspots (Myers et al. 2000) and as centers of endemism for tropical species.Endemism has often been used as a criterion for choosing areas for conservation purposes (Prevedello and Carvalho 2006).Dorstenia carautae C.C. Berg, for example, is endemic to Brazil and exclusively found in forest environments in advanced stage of regeneration (Berg 2001).In the state of Rio Grande do Sul, Dorstenia tenuis Bonpland ex Bureau and D. brasiliensis were included in the List of Endangered Species according to the state decree no.42099 of Dec 31, 2002(Assembléia Legislativa 2013).The present contribution is thus aimed to present a synopsis of the Dorstenia species occurring in Rio Grande do Sul, Southern Brazil, within the austral distributional limits of the genus in the Americas.Additionally, diagnostic morphological (either vegetative or floral) features are highlighted as well as relevant distributional and ecological informations for each species.

MATERIALS AND METHODS
The descriptions were made by analyzing live specimens and herbarium material.The following herbaria were consulted: F, FLOR, FURB, HAS, HB, HUCS, HUEFS, ICN, K, MBM, NYBG, P, PACA, PEL, RB, SMDB, SP, SPSF, U, UFP, UPCB, US, acronyms according to Thiers (2013), and UNILASALLE (Herbarium, University La Salle, Canoas, Brazil, not listed in the Index Herbarium).Phenological data and details like coloration, coenanthium and floral features were obtained through the monitoring of specimens, and observations made during field trips complemented by herbarium labels.A detailed photographic record of diagnostic vegetative and floral features was made, aiming to illustrate features or structures not shown or poorly shown in preceding literature.Vegetative and reproductive characteristics were measured based on living and pressed specimens using a pachymeter.The geographical distribution and habitat of the species was obtained from herbarium data, field observations and collections, as well as from literature (Carauta 1978, Carauta et al. 1996, Berg and Hijman 1999, Berg and Simonis 2000, Berg 2001).The popular names cited were obtained from the literature and from annotations on studied pressed specimens.Fieldwork extended from 2011 to 2013.A total of 24 field trips were made in Southern Brazil, state of Rio Grande do Sul.Phytoecological units and transitional vegetation areas in the south of Brazil were classified according to IBGE (2012) and the physiographic subdivisions according to Fortes (1959).The procedures used during these collections follow Mori et al. (1989).The collections were pressed and incorporated into the ICN Herbarium.Infrageneric divisions follow Berg and Hijman (1999) and Berg (2001).Abbreviations for authorities for plant names follow Brummitt and Powell (1992).The protologues and related taxonomic literature were consulted through BHL (2013) and Botanicus.org (2013).Highdefinition digitalized images of type specimens were consulted through Jstor Plants (2013).For morphological terminology, we refer to Radford et al. (1974), Font-Quer (1985) and Harris and Harris (2001).For colour terms, we follow Kornerup and An Acad Bras Cienc (2015) 87 (2) 927 Dorstenia IN RIO GRANDE DO SUL, SOUTHERN BRAZIL Wanscher (1978).Photos of general features of plants, such as habitat and habit were made with the help of a digital camera Sony ® Alpha 100 and Sony ® Cybershot DSC H7.Details were photographed with the aid of microscopic digital camera Dnt® 2.0 DigiMicro Scale and a binocular stereoscope coupled with a Leica ® digital camera.In order to assess risk categories according to IUCN criteria (IUCN 2013), the standard procedures suggested by IUCN were followed.The compilation of the data was carried in an outline form from the Live-system software (http://www.liv.fzb.rs.gov.br/).This platform was developed to assess the conservation status of species and preparation of the list of endangered flora in the state of Rio Grande do Sul, according to the IUCN criteria.The geographical distribution maps were produced using software ArcMap ESRI ArcGIS ® 10.

Phenology:
The coenanthia are fragile and usually small.They may or not present overlapping of sexual phases.The coenanthia exhibit variations in shape during their developing.Fruit production occurred twice a year between the months of May and June and again in the months of December and January.
Habitat and ecology: Occurs in forests, from middle to advanced process of regeneration, growing in shady and humid understory; usually near water bodies.According to Berg (2001), this species is found at low elevations.In Rio Grande do Sul, it was collected at an altitude of 216 m.
Conservation status: According to the IUCN (2013) criteria, the species is considered, at the State of Rio Grande do Sul as critically endangered: CR B2b(ii)-the estimated area of occupancy is less than 10 km 2 , and the field observations indicate a continuing decline of habitat quality;-the size of the observed population was of some hundreds of mature individuals.Therefore, D. carautae should be included in the Official List of Threatened Species of Rio Grande do Sul's Flora.In addition, the whole distribution of this taxon in Brazil coincides with the endangered Atlantic Forest biome, which currently presents less than 7% of its original cover (Myers et al. 2000).

Dorstenia tenuis
Coenanthium generally triangular, inside of a violet-brown receptacle, centrally attached, 0.4-2 cm diameter; outside green and puberulous; at the margin there are bracts in 3 rows or overlapping, ovate to orbicular, green to violet, puberulous, ciliolate, 0.05 cm long.Staminate flowers, 0.01 cm long, inserted between the pistillate ones, 0.01 cm long, sometimes aggregated at the thickened and bent edges; tepals 2, stamens 2, anthers white, BRUNA O. BOENI and RODRIGO B. SINGER and Uruguay (Berg 2001, Carauta 1978).In Rio Grande do Sul, D. tenuis occurs in semideciduous seasonal forest and mixed ombrofilous forest and doesn't occur in dense ombrofilous forest.Notes: Belongs to the Section Emygdioa (Berg and Hijman 1999).Popularly known as violeta-damontanha, contra-erva and canapia.Berg (2001), however, the latter is a valid species at the Lista da Flora do Brasil (Romaniuc-Neto et al. 2014).D. brasiliensis is a highly polymorphic species and widespread in South America.Due to its wide distribution and morphological variation, this species is part of a not well elucidated complex.Berg (2001) in his work for the Flora Neotropica, considered D. brasiliensis as a polymorphic species and assumed that the variation in leaf and coenanthia traits were mainly due to environmental variation.Observed morphological variations in coenanthia of Dorstenia brasiliensis, sampled in Rio Grande do Sul are presented on Figure 7.

Figure 1 -Figure 2 -
Figure 1 -Dorstenia carautae C.C. Berg. A. Habit.B. Detail of stem and leaves; notice the elongate internodes.C. Detail of the plant.D. Adaxial surface of leave with sparse trichomes.E. Adaxial surface of leave with conical trichomes.F. Abaxial surface of leave, puberulous.Scale bars: A and C = 10 cm; B = 1 cm; D-F = 1 mm.

:
The coenanthia are fragile and usually small.The staminate and pistillate flowers may bloom or not at the same time.Staminate and pistillate flowers ripen in November and fruiting occurs in May.During the cold season the production of coenanthia decreases.Habitat and ecology: Grows in dark and humid places, usually near water bodies, at the forest understory.It is common for this species to develop near the base of trees or on substrates like rocks and remains of dead trunks.This species dwells in forests at medium and advanced stages of regeneration, being very sensitive because it is not likely to occur in disturbed environments.It is found at low altitudes, between 253 to 615 m.Conservation status: This species was considered at risk of extinction, in the Endangered category, at the regional list of endangered species of Rio Grande do Sul, according to the state decree no.42099 of Dec 31, 2002 (Assembléia Legislativa 2013).It was also included into the National list of threatened flora of 2008 (Ministério do Meio Ambiente 2008) being excluded from the current version (Romaniuc-Neto et al. 2013).However after a reevaluation of this taxon in Rio Grande do Sul according to the IUCN (2013) criteria, the species is considered Least Concern (LC)-not qualifying for a higher risk category, being an abundant and widely distributed taxon.During the last years we have found several and abundant populations, all scattered along the Serra do Sudeste and Alto Uruguay, therefore, D. tenuis should not be included in the Official List of Threatened Species of Rio Grande do Sul's Flora.