Two new species of Mikania Willd. (Asteraceae: Eupatorieae) from

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Introduction
Mikania is a pantropical genus of Asteraceae with around 450 species distributed mainly in South America (King & Robinson 1987;Robinson et al. 2009;Godoy et al. 2017).It is the largest genus of tribe Eupatorieae and the only member of subtribe Mikaniinae.Mikania has traditionally been recognized as a natural group, mostly due to its conserved morphology.Most species have lianescent habit, capitula with a variously positioned subinvolucral bract, four involucral bracts and four florets in each capitulum, and five-ribbed cypselae, rarely ten-ribbed (Ritter & Miotto 2005;Hind & Frisby 2014;Contro & Nakajima 2017).Although Mikania is mostly distributed in forested environments, 41 of the 198 species currently recognized in Brazil (Ritter et al. 2020) occur in campos rupestres (highland rocky fields).This phytophysiognomy is associated to sandy soils and rock outcrops in the Espinhaço Range (ER), a mountain chain extending over 1,000 km in a North-South axis along the central portion of the States of Minas Gerais and Bahia (Giulietti et al. 1997;Alves & Kolbeck 2010;Fernandes 2016).The ER is situated in the ecotone among three phytogeographical domains: the Atlantic Forest to the east, the Caatinga to the north, and the Cerrado to the west.Other large disjunct areas of campos rupestres are found within the Cerrado domain in western Minas Gerais and in the State of Goiás, within the Amazon Forest domain, mainly in the State of Pará, and in isolated patches in the State of Mato Grosso do Sul and in eastern Bolivia (Fernandes 2016;Silveira et al. 2016;Zappi et al. 2019;Miola et al. 2021).
Recently, smaller disjunct patches of campos rupestres were discovered on quartzitic outcrops that are entirely inserted in the Atlantic Forest phytogeographic domain (Gonella et al. 2015;Lopes et al. 2016;Siniscalchi et al. 2016;Mello-Silva 2018).These areas located in the Rio Doce valley in eastern Minas Gerais, namely Serra do Padre Ângelo, Pico da Aliança, and Sete Salões State Park, possess some floristic elements related to the ER (Siniscalchi et al. 2016;Mello-Silva 2018;Andrino & Gonella 2021;Antar et al. 2021a), but also to the granitic inselbergs typically found in the surrounding Atlantic Forest (Antar et al. 2021b;Mezzonato-Pires et al. 2021).With an increasing number of taxonomic novelties described in recent years, these areas corroborate the elevated species richness and endemism of the campos rupestres (Giulietti et al. 1997;Fernandes 2016;Colli-Silva et al. 2019), but also highlight the botanical sampling deficit in Brazil.Biological knowledge shortfalls, mainly related to taxonomy and geographical distribution of species (the Linnean and Wallacean shortfalls, respectively; Lomolino 2004), have been identified in recent times; their effects and the spatial accuracy of biodiversity documentation in the Atlantic Forest domain have been recently discussed and analyzed by Colli-Silva et al. (2020).
In the present work, we describe two new species of Mikania endemic to the campos rupestres of Pico da Aliança (1440 m a.s.l.) and Pico do Padre Ângelo (1550 m a.s.l.) in the State of Minas Gerais, which were identified after recent botanical expeditions in these areas.We provide full descriptions, illustrations, and preliminary conservation assessments, as well as taxonomic and ecological comments for each species.

Materials and methods
The morphological descriptions were based on herbarium specimens studied in the following herbaria: BHCB, MBML, RB, and SPF (acronyms according to Thiers, continuously updated).Fieldwork was carried out in Serra do Padre Ângelo and Pico da Aliança from 2013 to the present.A 10-60 × magnification stereomicroscope was used to analyze morphological features of the specimens, with measurements based on rehydrated or dry herbarium material.Terminology follows Harris & Harris (2001) for general morphology and Hickey (1973) for leaf shape, as well as King & Robinson (1987), Ritter & Miotto (2005), Oliveira et al. (2016) and Antar et al. (2021c) for Asteraceaerelated terms.
The Geospatial Conservation Assessment (GeoCAT) tool (Bachman et al. 2011) was used along with IUCN (2012) criteria to infer conservation status.The IUCN default values were used for Extent of Occurrence (EOO) and Area of Occupancy (AOO) analyses in GeoCAT.The distribution map was produced in QGIS version 3.14.15(QGIS Development Team 2020) using layers downloaded from FBDS (2021), IBGE (2021) and SISEMA (2021).Mikania semirii resembles Mikania phaeoclados as both share the climbing habit and ovate leaves with cordate or rounded base and serrate margins, but differ in leaf indumentum (adaxially glabrous except for pubescent or glabrescent primary and secondary veins with simple curved trichomes, abaxially glabrescent with scattered, small simple trichomes in M. semirii vs. adaxially strigose, abaxially tomentose), shape and position of subinvolucral bracts (4.0-6.1 × 2.2-3.0 mm, elliptic, located below the capitulum in M. semirii (Fig. 2C) vs. 1.6-2.6 × 0.6-0.9mm, oblong-lanceolate, located at the base of the peduncle) and peduncle size (sessile to 1 mm long in M. semirii vs. 1.1-3.5 mm long).
Etymology: The species epithet honors the late botanist Dr João Semir , professor of the Botany Department of UNICAMP, Campinas, São Paulo, Brazil.Dr Semir was a synantherologist who greatly contributed to the systematic knowledge of Asteraceae in Brazil, especially in Vernonieae, but also in Bignoniaceae, Malvaceae, and Orchidaceae.Dr Semir mentored several Brazilian botanists and is recognized as a pioneer of floristic studies of the campos rupestres.
Preliminary Conservation Status: Critically Endangered: CR B2ab(i, ii, iii).Mikania semirii was found exclusively on summits (at elevations above 1400 m a.s.l.) of two of the highest peaks located in the eastern Minas Gerais quartzitic formations, Pico do Padre Ângelo (part of Serra do Padre Ângelo) and Pico da Aliança, ca. 12 km distant from each other.At both sites, the number of individuals observed was less than 20, but exploration of the habitat is hindered by the rugged relief.Similar habitats and elevations may be further found at Pico do Pinhão and the virtually inaccessible Pico do Sossego (both part of Serra do Padre Ângelo).All these areas are susceptible to invasion by alien grasses, most remarkably "capim-gordura", Melinis minutiflora (Gonella et Acta Botanica Brasilica, 2022, 36: e2021abb0329 al. 2015), which can be further aggravated by the lack of management and control.Invasion by alien species can be also intensified by wildfires, which are a common practice for pasture renovation in the surrounding areas that had their original vegetation extensively modified (Fig. 1).None of the occurrence areas are included in protected areas, therefore leaving the species habitat susceptible to human disturbance (including predatory collection of plants, garbage dumping, trampling, fire, etc.).Similar to other endemic species of Serra do Padre Ângelo, the population of M. semirii was affected by an anthropogenic fire of large proportions in late 2020 (Andrino & Gonella 2021;Antar et al. 2021b;Kollmann & Gonella 2021).Additionally, mountaintop-restricted endemics are severely threatened by climatic change, as they cannot migrate to higher elevations to remain in their climatic envelopes.Based on the restricted range (AOO of 8 km 2 ) and the listed threats, M. semirii should be listed as Critically Endangered based on IUCN criteria B2ab(i, ii, iii) (IUCN 2012).
Distribution and Habitat: Mikania semirii is probably endemic to Serra do Padre Ângelo and Pico da Aliança in the municipalities of Conselheiro Pena and Alvarenga, respectively, in the State of Minas Gerais (Fig. 1).It is found in the highest areas of these peaks, near the summits, growing in campos rupestres vegetation, in sandy soils with organic matter among rock outcrops, from 1430 to 1500 m a.s.l.
Phenology: Mikania semirii was found fertile in the dry season, in June, July, and August.
Affinities and morphological notes: Mikania semirii presents a unique combination of the following features: lianescent habit; ovate leaf blade, with cordate or rounded base, adaxially glabrous and abaxially glabrescent, with serrulate, revolute to slightly revolute margins.The subinvolucral bracts are elliptic and located directly beneath the capitulum, the peduncles are sessile to 1 mm long and the involucral bracts pinkish or whitish.
The new species is morphologically similar to M. phaeoclados which also occurs in the State of Minas Gerais, but their distributions do not overlap.Mikania funkiae is morphologically similar to Mikania glauca, as both share a similar shrubby habit, and glabrous leaves with slightly revolute margins.However, they differ in that M. funkiae possesses coriaceous leaves without wax (vs.leaves chartaceous, mostly waxy), petiole 0.3-0.6 cm long (vs.petiole absent to 1 mm long), leaf margins with 3-4 pairs of obtuse teeth above the mid portion of the blade (vs.blade entire or sinuate) and leaf shape oblate or wide elliptic (vs.wide elliptic or suborbiculate).
Etymology: The species epithet honors the late botanist and synantherologist Dr Vicki Ann Funk , who was a Senior Researcher and Curator at the Smithsonian National Museum of Natural History, Washington D.C., United States of America.Dr Funk greatly contributed to the knowledge of Asteraceae as well as to the understanding of phylogenetic relationships and biogeography of the family.
Preliminary Conservation Status: Critically Endangered: CR B2ab(i, ii, iii).Mikania funkiae is currently known only from the type collection at the summit of Pico da Aliança (Fig. 1), where less than 20 individuals have been observed, which suggests it is a rare and microendemic species.The taxon is not protected by any conservation area, and is vulnerable to the same threats listed above for M. semirii, therefore being assessed as Critically Endangered based on criteria B2ab(i, ii, iii) of IUCN (IUCN 2012).
Distribution and Habitat: Mikania funkiae is probably endemic to the summit of Pico da Aliança, in the municipality of Alvarenga, State of Minas Gerais.It is found growing in campos rupestres in dry sandy soils among rocks, at around 1400 m a.s.l.(Fig. 1).
Phenology: Mikania funkiae was found fertile in August.
Affinities and morphological notes: Mikania funkiae has the following unique combination of characters: shrubby habit, opposite, petiolate leaves that are coriaceous, orbiculate, oblate or wide elliptic, with slightly revolute margins, and sessile or shortly pedunculate inflorescence, with peduncles up to 2 mm long.The new species is morphologically similar to Mikania glauca, which also occurs in Minas Gerais State but not recorded in the same region.Both species differ by the features indicated in the diagnosis.Mikania funkiae is also similar to M. obtusata based on the shrubby habit, opposite, glabrous leaves with attenuate base and slightly revolute margins, and similar petiole length.However, the new species differs from M. obtusata by the presence of 3-4 pairs of obtuse teeth above the mid portion of the blade (vs.margins entire, repand), coriaceous leaf texture (vs.chartaceous) and oblate or broad-elliptic blade (vs.elliptic).

Final remarks
Species of Mikania are usually widely distributed and without a very specific niche.A few species are microendemics and/or exclusive of restricted habitats, such as some Cerrado and campo rupestre taxa (e.g.M. nelsonii, Hind 1993; Acta Botanica Brasilica, 2022, 36: e2021abb0329 M. fasciculata, Oliveira et al. 2016;M. cipoensis, Ritter et al. 2020).The distribution pattern documented herein for M. semirii and M. funkiae, restricted to the summits of two mountaintops within the Atlantic Forest domain, has not been previously reported for the genus.Further collection efforts are needed to confirm the restricted distribution of these two new taxa, as well as ongoing phylogenetic studies that may shed light on their evolution and origin.
The present results highlight a well-documented gap in botanical collections in Brazil and South America as a whole (Mori et al. 2011;BFG 2015;Morim & Lughadha 2015;Oliveira et al. 2017Oliveira et al. , 2019)).Even though the Atlantic Forest is one of the most intensively collected Brazilian phytogeographic domains (Oliveira et al. 2019), the few expeditions carried out so far in the underexplored areas of Serra do Padre Ângelo and Pico da Aliança have revealed 24 new taxa in different angiosperm families, including the two new species proposed herein.This study highlights the need for more botanical expeditions and sampling effort in these mountains, as well as the importance of active conservation plans for these localities.

Figure 1 .Figure 2 .
Figure 1.Geographic distribution of Mikania semirii C.T.Oliveira & Antar (white circles) and Mikania funkiae C.T.Oliveira & Antar (white star) in eastern Minas Gerais, with land use projected over a satellite image and highlighting the limits of the only protected area in the region (Sete Salões State Park).In the reference maps to the right, the green shadowing represents the Legal Atlantic Forest area.State acronyms, BA: Bahia, ES: Espírito Santo, MG: Minas Gerais.