The Paepalanthoideae (Eriocaulaceae) of the Chapada dos Veadeiros National Park, Brazil: taxonomic novelties, identification key, and illustrated list of species

. The Chapada dos Veadeiros National Park is a conservation unit established to preserve the highest savannahs of Central Brazil and their unique biodiversity. Eriocaulaceae are a relevant and conspicuous family in such high savannahs, but its diversity is poorly known, documented solely in general lists or in isolated efforts aimed at small groups. After a structured series of field expeditions and analysis of specimens from the relevant herbaria, we provide nomenclatural novelties, a first identification key, and an illustrated checklist for the species of Paepalanthoideae (Eriocaulaceae) in the area. We recorded 42 species of Paepalanthoideae from the Chapada dos Veadeiros National Park: Actinocephalus (Körn.) Sano (2 spp.), Comanthera L.B.Sm . (1 sp.), Paepalanthus Mart. (24 spp.), and Syngonanthus Ruhland (15 spp.). Actinocephalus brevifolius Trovó & Echtern. sp. nov. and P. irwinii Trovó & Echtern. sp. nov. are newly described species and P. politus Trovó stat. et nom. nov. is a variety of P. elongatus (Bong.) Körn. raised to the species status with a new name. The generic and specific composition shows predominance of Paepalanthus and Syngonanthus , and with a low representation of Actinocephalus and Comanthera , as expected, outside of the Espinhaço Range. More than 50% of the species (22 spp.) are endemic to the area and 25 species are endemic to Central Brazil, the area being the main center of diversity for dimerous-flowered groups. The non-endemic diversity is a combination of widespread species and marginal distribution of species typical from the Amazon and southeastern savannahs. The species are unevenly distributed in the area, with their occurrence correlated to altitude, water availability, and lithology. We reinforce that the savannahs from Central Brazil are a secondary center of diversity for Eriocaulaceae, playing a central role in the conservation of an unique and irreplaceable piece of its diversity and the Cerrado biome as well. Fernandes al. As a result of a series of botanical expeditions to the Chapada dos Veadeiros Region and visits to the relevant herbaria, we present an illustrated checklist of the Paepalanthoideae (Eriocaulaceae) for the Chapada dos Veadeiros Region, comprising also two new species, one new status accompanying a new name, and a first identification key. 0.5 mm long; sepals free, narrowly obovate, castaneous with central whitish stripe, ca 2.5 mm long, mostly glabrous or sparsely pilose distally on the abaxial surface, densely ciliate toward the acute apex, glabrescent; anthophore fleshy, elongated, ca 1.5 mm long; petals fused into a tube, whitish, membranaceous, ca 0.5 mm long; stamens ca 0.8 mm long, cream-colored; carpellodes 3, papillose. Pistillate flowers ca 2.5 mm long, sessile or subsessile; sepals free, dolabriform, whitish, ca 2.0 mm long, densely pilose abaxially, densely ciliate toward the obtuse apex, glabrescent; petals free, dolabriform, whitish, ca 1.5 mm long, sparsely pilose abaxially, ciliate toward the obtuse to mucronate apex, glabrescent; gynoecium 2.5 mm long, stigmatic branches bifid at the apex, twice as long as the nectariferous branches, staminodes not seen. Fruit a loculicidal capsule. Seeds ellipsoid, reddish.


Study Area
Located in the northeast of the state of Goiás, the Chapada dos Veadeiros National Park ( Fig. 1) was established in 1961 and originally covered an area of 625 000 ha. After being severely reduced to ca 10% of its original area, a recent extension was enacted and the current park area is of ca 240 000 ha, encompassing the municipalities of Alto Paraíso de Goiás, Cavalcante, Colinas do Sul, São João D'Aliança, Teresina de Goiás, Nova Roma, Monte Alegre de Goiás, and Campos Belos (Brazilian Ministry of the Environment 2017; ICMBIO 2021). The park hosts the highest savannahs in Central Brazil, ranging in altitude from 500-1650 m a.s.l. and comprising different Cerrado phytophysiognomies (Munhoz & Felfili 2006;Felfili et al. 2007). Climatic conditions include rainy summers and dry winters, with mean annual rainfall ranging from 1500 to 1750 mm and mean temperatures from 20 to 25°C (Felfili et al. 2007). In order to evaluate species distribution within the conservation unit, the park was roughly divided into three areas according to the combination of their respective geomorphologies, lithotypes, and altitude: the Rio Preto Valley (between latitudes 47.9 and 47.6° S, and altitudes from 800-1150 m), belonging to the geomorphological unit SRA I, an old formation comprising mostly quartzitic feldspathic rocks; the Pouso Alto (between latitudes 47.6 and 47.3°S, and altitudes from 1150−1650 m), also belonging to the geomorphological unit SRA I; and the Chapada de Nova Roma (between latitudes 47.3 and 47.0° S, and altitudes from 800−1000 m), belonging to the SRA IIa geomorphological unit, comprising mostly quartzitic arcosean rocks (Latrubesse & Carvalho 2006;Silva & Cherem 2016;SIEG 2021).

Data collection
The checklist is based on both field efforts and visits to relevant herbaria. Field trips to the Chapada dos Veadeiros National Park began sporadically in 2005. From 2015 to 2020, structured field efforts comprising 11 fieldtrips were conducted to maximize the sampled area within the park and to cover the flowering period of the species. A few species growing explicitly in the vicinity of the park are also included in the checklist. The photos of the illustrated checklist were made directly in the field. The following herbaria were analyzed (acronyms according to Thiers, continuously updated One voucher per species is cited. . The specimens marked with an asterisk are type specimens. Additional records can be consulted using online platforms of virtual herbaria (www.splink.org.br/; jabot.jbrj.gov.br/; www.sibbr.gov.br). Numbers between square brackets in the species protologs correspond to herbarium barcodes. Herbarium specimens were analyzed under a Leica EZ4 stereoscopic microscope with camera, and identified using Ruhland (1903), the series of Moldenke manuscripts usually published in Phytologia, and recent revisions of specific groups. The subfamily Eriocauloideae in Brazil is represented only by Eriocaulon L., a genus currently under review and pending many nomenclatural adjustments (Chagas 2017); it is therefore not included in this treatment. The measurements concerning Actinocephalus phaeocephalus (Ruhland) F.N.Costa and Paepalanthus acanthophyllus Ruhland follow the protologs, Costa (2005), Trovó (2010), and additional field observations.

Etymology
The epithet "brevifolius" is related to the species' small leaf size both when compared to the morphologically similar species and also in relation to the size of its paraclades.

Distribution, habitat, and conservation
A few populations with ca 15−50 flowering individuals of Actinocephalus brevifolius sp. nov. were observed along the margins of unpaved roads in the Chapada dos Veadeiros National Park. All known populations are restricted to the same area in the Rio Preto Valley in the vicinity of the Morro da Baleia Region. Some of these populations are at risk of disappearing, as they occur along roads frequently used by tourists and locals, but at least one population occurs in a less exposed area, close to the Vereda do Mulungu. The individuals were found growing in dry to humid soil along the border of moist grasslands.  According to the IUCN (2019) distribution criteria, EN: B1ab (i,ii,iii,iv), and its occurrence inside a National Conservation Unit, the species should be considered Endangered.

Notes
Actinocephalus brevifolius sp. nov. is one of the few species of Actinocephalus occurring in Goiás State (Sano 2004;Costa & Sano 2013;Andrino et al. 2021). The most similar species to A. brevifolius is Actinocephalus phaeocephalus, the only congeneric and sympatric species in the Chapada dos Veadeiros Region. Although Andrino et al. (2021) refers Actinocephalus phaeocephalus as endemic to the Chapada dos Veadeiros, it is worth mentioning that the species is also distributed southwards, as the type of Actinocephalus phaeocephalus var. foliosus (Moldenke) F.N.Costa & Andrino was collected in the vicinities of Brasília.

Diagnosis
Differs from Paepalanthus acanthophyllus by being a more gracile plant with shorter, linear leaves, shorter and narrower reproductive axis, shorter, linear to narrowly lanceolate axis bracts, fewer scapes per plant, capitula usually narrower, and petals of the pistillate flower with obtuse to mucronate apex.

Etymology
The epithet "irwinii" honors Howard Samuel Irwin, the coordinator of the Planalto Expeditions Program, which collected over 225 000 specimens and over 30 000 numbers in Central Brazil by 1972 (NYBG 2021). The Eriocaulaceae set of specimens from the "Planalto Expeditions" is precious, encompassing many type specimens.  Silva et al. 1921; RB, SPF • same locality as for

Distribution, habitat, and conservation
Populations of Paepalanthus irwinii sp. nov. with ca 10−75 flowering individuals were frequently found in the Chapada dos Veadeiros National Park. Different from most of the endemic species of Eriocaulaceae to the area, which are locally restricted, the species is distributed from the Rio Preto Valley in the vicinity of São Jorge village to the Pouso Alto Region. Populations occur in different phytophysiognomies, from open fields to rupestrian savannahs, but the individuals grow only over shallow, usually wet, rocky soils. It is also worth mentioning that many individuals were seen in flower after a severe fire event in 2017. Based on the IUCN (2019) distribution criteria, EN: B1ab (i,ii,iii,iv), and its occurrence inside a National Conservation Unit, the species should be considered Vulnerable.

Notes
Paepalanthus irwinii sp. nov. belongs to Paepalanthus sect. Diphyomene Ruhland, one of the few categories of Paepalanthus mostly diversified in the Chapada dos Veadeiros Region Trovó et al. 2013). The species is morphologically most similar to P. acanthophyllus due to its general habit, deciduous leaves, patent and spiny axis bracts, and the shape and color of the capitula and involucral bracts. Paepalanthus irwinii is distinguished by being a more gracile plant up to 60 cm tall (vs up to 120 cm); with shorter and narrower, linear leaves, 1.0−3.0 × 0.1−0.2 cm (vs lanceolate, 3.5−8.0 × 0.3−0.7 cm); shorter and narrower reproductive axis, ca 45.0 cm tall and 0.3 cm diam. (vs longer and wider, ca 100.0 cm tall and 0.6 cm diam.); linear to narrowly lanceolate axis bracts, 0.5−1.5 × 0.1−0.3 cm (vs lanceolate, 1.0−5.5 × 0.8−1.2 cm); up to 25 scapes per plant (vs up to 80 scapes per plant); narrower capitula, ca 0.9 cm diam. (vs wider, ca 1.5 cm diam.); and the petals of the pistillate flower with obtuse to mucronate apex (vs petals of the pistillate flower with obtuse to rounded apex). Although sympatric, these species grow in different habitats and flower at different times. While P. irwinii occurs over shallow, rocky soils, P. acanthophyllus occurs over a more consolidated argillaceous soil. Individuals of the new species are usually seen in flower and fruit from November to May, while P. acanthophyllus is usually fertile from April to August.  Moldenke (1979) briefly described Paepalanthus elongatus var. glabrescens based on a single collection (G. Hatschbach 36772), distinguished from the typical variety solely by its narrow leaves and glabrous or subglabrous spathes. Trovó (2018) considered such character states as within the morphological variation of Paepalanthus elongatus var. elongatus and proposed its synonymization. Trovó (2018) also commented that two isotypes (G. Hatschbach 36772 MO, UPCB) were annotated by Moldenke himself in 1975 as Paepalanthus elongatus var. angustifolius Silveira, enhancing the fragile delimitation of such taxa. Herbarized specimens of P. politus are indeed tricky to distinguish from the bulk of the P. elongatus species complex and may explain such nomenclatural instability.

Notes
During our field trips, , we located a single population in the Rio Preto Valley of what we first thought to be a new species. When analyzing the dried specimens for this manuscript, it became clear that such specimens belong to the taxon described by Moldenke (1979) as Paepalanthus elongatus var. glabrescens. It is, however, much different from Paepalanthus elongatus var. elongatus due not only to the characters pointed out by Moldenke (1979), but mainly by its bright and completely glabrous involucral bracts slightly surpassing the floral disc (vs opaque and pilose, densely ciliated involucral bracts largely surpassing the floral disc). The position, the apex, and the color of the involucral bracts are also noteworthy and different. In P. politus, , the bracts of all series are patent; with an acute apex; and with a paleaceous central stripe, while in P. elongatus var. elongatus the inner bracts are recurved; all bracts have a long acuminate apex; with a dark castaneous central stripe. The taxon deserves thus the species status with a new name, as the epithet "glabrescens" is already taken (Hensold 2017). The epithet "politus" is related to the shiny involucral bracts, with a polished aspect. A complete description of the species will be available in a forthcoming revision of Paepalanthus ser. Dimeri (Ruhland) Giul.

Distribution
Endemic to the Chapada dos Veadeiros. A rare species probably restricted to the lower parts of the park on dry, rocky soils in the Rio Preto Valley. Fig. 8E Voucher H.S. Irwin 33091 (NY).

Distribution
Distributed in the sandy savannahs of North and Central-West Brazil. Widely distributed from the Rio Preto Valley to the Pouso Alto Region, growing usually on dry, sandy soils.  Trovó et al. 771 (RB).

Distribution
Widely distributed in the Cerrado Biome in South America. Known from a single population in a wet, argillaceous area in the Pouso Alto Region, close to the Cruzeiro entrance. Fig. 9G Voucher M.L.O. Trovó et al. 778 (RB).

Distribution
Widely distributed from Mexico to Central Brazil. Widely distributed in the three areas of Park, forming small populations on wet to dry, sandy soils.

Distribution
Endemic to Chapada dos Veadeiros. The species is known from a few old specimens collected along the GO-118 road, a few km south of the Chapada dos Veadeiros. This species grows on wet, sandy soils in an area nowadays suffering from high levels of anthropic activity.

Distribution
Widely distributed in eastern Brazil, from Piauí to São Paulo. Known only from perennial streams and rivers in the Pouso Alto Region.

Species list and geographical distribution
We recorded a total of 42 species of Paepalanthoideae from the Chapada dos Veadeiros National Park, belonging to the following genera: Actinocephalus (2 spp.), Comanthera (1 sp.), Paepalanthus (24 spp.), and Syngonanthus (15 spp.). The generic and specific composition is as expected from the Cerrado vegetation outside of the Espinhaço Range, with a predominance of Paepalanthus and Syngonanthus, and with a low representation of Actinocephalus and Comanthera (Giulietti & Hensold 1990;Stützel 1998;Giulietti et al. 2012). Leiothrix Ruhland was not recorded from the area, not even Leiothrix flavescens (Bong.) Ruhland, a widely distributed species in South America. The area is especially significant for the species of Paepalanthoideae with dimerous flowers, being the main center of diversity for groups such as Paepalanthus sect. Conodiscus Ruhland, Paepalanthus sect. Diphyomene, and P. ser. Dimeri (Trovó et al. 2013(Trovó et al. , 2015a(Trovó et al. , 2017Trovó 2018;. Interestingly, the only recorded Comanthera is dimerous and endemic to Chapada dos Veadeiros (Echternacht et al. 2015). According to Chagas (2017), at least 11 species of Eriocaulon occur in the Chapada dos Veadeiros National Region, most of them endemic and yet to be described. The whole species of Eriocaulaceae richness is thus not only significant by itself, but even more so when compared to other areas already surveyed. The Chapada dos Veadeiros National Park is richer in species of Eriocaulaceae than other areas of Cerrado and Mata Atlântica vegetation, as for example in the states of São Paulo (49 spp.) and Rio de Janeiro (36 spp.), the core Mantiqueira Range (24 spp.), and the Ibitipoca State Park (22 spp.) (Ferreira et al. 2011;Sano & Giulietti 2012;Trovó et al. 2015b;Baumgratz et al. 2021). It is also richer than areas within the main center of diversity in the Espinhaço Range, such as the Grão-Mogol Region (33 spp.) . The results reinforce the highest savannahs from Central Brazil as a secondary center of diversity for Eriocaulaceae in Brazil and may be even more representative when considering the remaining areas beyond the Chapada dos Veadeiros National Park (Giulietti & Hensold 1990;Stützel 1998). Efforts to expand the herbarium collections and checklists of Eriocaulaceae in the Central Brazilian Plateau are urgent and may play a critical role in the conservation of a unique and irreplaceable piece of the Eriocaulaceae diversity and the Cerrado biome as well.

Dubious taxa and specimens
Some specimens previously described and identified with dubious names or yet to receive a proper identification were kept out from the checklist. Such specimens were usually maintained at the generic level or re-identified. We would like, however, to provide comments on such specimens and names for further investigations.
Regarding Paepalanthus, the name Paepalanthus fasciculifer var. capillifolius Moldenke described from the Chapada dos Veadeiros indeed belongs to Syngonanthus Ruhland, according to Echternacht (2012) and its proper synonymization under a species of Syngonanthus is yet to be published. Many specimens were identified as P. microcaulon Ruhland in the herbaria visited. We assume these specimens as corresponding to P. polytrichoides and further investigations should elucidate the circumscription of these two taxa, as we did not find enough differences to maintain both names as corresponding to distinct entities.
The specimens of C.B.R. Munhoz 7844 (RB, UB) were previously identified as P. scholiophyllus Ruhland. This species is recorded from other areas in Central Brazil, but the two specimens from the study area correspond to vegetative rosettes of difficult identification. In addition, these specimens represent a single collection gathered in an intensively surveyed area of the park, though the species has never been recollected. The specimen J.P Souza 8657 (SPF) resembles P. lycopodioides Silveira, a rare species from the Espinhaço Range. Intense efforts to recollect this material have failed and we leave the specimen at the generic level rather than assume such geographic disjunction until further specimens are available. Finally, the specimens M.L Fonseca 6932b (IBGE, RB) may represent a new species from the park or a variation of similar species, such as P. echinoides and P. sphaerocephalus. We, however, failed to recollect the taxon and decided to wait for additional specimens or further revisionary studies.  Parra et al. (2010). The specimen, however, differs from C. kegeliana by the golden external series of involucral bracts (vs cream-colored) and the internal series surpassing the flower disc (vs not surpassing). In addition, its flowers are mostly immature and remain undescribed. It would represent an unlikely disjunction between the Amazon and the Cerrado Domain. In this treatment we do not recognize S. ulei var. goyasensis as synonymous with C. kegeliana. Additional analyses of the specimen, especially of the flowers, are needed to confirm its identity.
Regarding Syngonanthus, the taxon S. appressus var. chapadensis Moldenke is known only from a few specimens in the vicinities of the Chapada dos Veadeiros National Park. According to Echternacht (2012) and Watanabe (2015), an analysis of the type specimen, H.S. Irwin 32149 (LL), suggests that the species should be transferred to Paepalanthus. However, such analysis and nomenclatural adjustments are yet to be published. Finally, Syngonanthus davidsei belongs to the Syngonanthus gracilis (Bong.) Ruhland species complex. Indeed, many specimens were previously identified as S. gracilis in different herbaria. Based on the morphology of the stem and gynoecium of the specimens, besides the species distribution, we follow Nancy Hensold's concepts according to Echternacht (2012) and consider all specimens from the Chapada dos Veadeiros Region as belonging to S. davidsei.