Two new species of Microlicia D.Don (Melastomataceae, Microlicieae) from Chapada dos Veadeiros, Goiás State, Brazil

Abstract Microlicia gracilis and Microlicia xylopodifera, endemic to Chapada dos Veadeiros, Goiás State, Brazil, are described, illustrated and the conservation status is also provided. Both species resemble Microlicia ordinata and Microlicia ramosa that are also endemic to Goiás, by having sessile leaf with serrate and ciliate margin, pedicellate flower, triangular and short sepal and dimorphic stamens with bicolorous and polysporangiate anthers. However, M. gracilis differs by the long internode (2–4 mm long), concolorous, semi-amplexicaul and lanceolate leaf, and petal acuminate at the apex. Microlicia xylopodifera differs in having a robust xylopodium, horizontal or slightly ascending leaf and a dense crown of glandular trichomes at the apex of flower bud.

The Chapada dos Veadeiros, located in the north-eastern part of the State of Goiás, is considered an important floristic component of the Cerrado biome with different phytophysiognomies at elevations that vary from 800 to 1650 metres (Munhoz and Felfili 2006;Felfili et al. 2007;Souza and Bove 2011;Romero et al. 2017). The region stands out as one of the centres of diversity of Microlicieae, being related as a recent radiation area of the tribe, due to the high number of endemic rates and high endemicity scores (Pacifico et al. 2020b). The region exhibits a significant number of endemic species of Chaetostoma (Silva et al. 2018), Trembleya (Pacifico et al. 2019) and Microlicia (Pilger 1903;Wurdack 1959;Silva 2017a, 2017b;Romero et al. 2017). Moreover, at least 20 species of Microlicia in the State of Goiás occur in the Chapada dos Veadeiros (Naudin 1845;Cogniaux 1883;Pilger 1903;Smith 1955;Wurdack 1959;Almeda and Martins 2001;Romero et al. 2017;Diniz and Silva 2019).
Microlicia has been traditionally characterised in having solitary flowers with five, rarely six petals, free ovary with three or five locules and capsules with longitudinal dehiscence from the apex to the base (Almeda and Martins 2001;Romero 2003a). However, recent molecular studies show that Microlicia, as currently delimited, is paraphyletic and most of the morphological characters used for the circumscription of each genus in Microlicieae are homoplastic. Thus, species of Chaetostoma DC., Lavoisiera DC., Stenodon Naudin and Trembleya DC. will be included in Microlicia, resulting in a monophyletic genus (Versiane 2019).
In the course of preparing a taxonomic treatment of Microlicieae for the State of Goiás, some collections from Chapada dos Veadeiros could not be recognised under any name in the genus and so we concluded that these collections refer to two new undescribed species. The new species are described, compared morphologically with similar species and information about geographic distribution and conservation status is provided, as well as images of morphological structures of the two species.

Material and methods
This study was based on the morphological analysis of specimens of Microlicia from the following herbaria: HEPH, HUFU, IBGE, MBM, MO, NY, UB, UEC and US (acronyms according to Thiers 2020). Specimens seen on the online platforms Reflora Virtual Herbarium (2020, https://reflora.jbrj.gov.br/reflora/herbarioVirtual), speciesLink (2020, https://www.splink.org.br/) and Tropicos (http://www.tropicos.org) were referred to here with barcode numbers. For general morphological terminology, we follow Radford et al. (1974) and the indumentum terminology follows Wurdack (1986). The leaves, colour of the petals, stamens and style were observed only in dry material. According to georeferenced data from the cited collections, the area of occupancy (AOO) and extent of occurrence (EOO) were calculated using GEOCAT (Bachman et al. 2011). The conservation status was based on the IUCN guidelines and criteria (IUCN 2019). Images of vegetative and reproductive structures were obtained using a digital camera coupled to a Zeiss stereoscopic microscope and organised on Adobe Photoshop CS6. Diagnosis. The new species can be recognised by the long internode (2-4 mm long), lanceolate leaf blade, attenuate and semi-amplexicaul at the base, conspicuous calyx tube (0.2 mm long) and petal acuminate at the apex.
Conservation status. Microlicia gracilis has a restricted extent of occurrence (EOO = 10 km 2 ) and area of occupancy (AOO = 8 km 2 ) and, according to the IUCN Categories and Criteria (IUCN 2019), is preliminarily assessed as Critically Endangered [CR B1ab (iii) + 2ab (iii)]. So far, collections of M. gracilis have been made only outside the boundaries of the Chapada dos Veadeiros National Park and, therefore, it is not protected by any conservation units. The restricted distribution of M. gracilis also contributes to its degree of threat, since its populations are exposed to frequent burning caused by farmers, in addition to the expansion of agricultural borders in the region (Felfili et al. 2007;Alves et al. 2013).
Phenology. Flowers have been collected in March, May and June and fruits in May and June.
Etymology. The specific epithet "gracilis" refers to the very delicate and fragile branches and leaves and the small size of the flowers.  Diagnosis. The new species can be recognised by the robust xylopodium, cespitose habit, indumentum of spherical glands, setose and glandular trichomes on branch, leaf, hypanthium and sepal and flower bud with a dense crown of glandular trichomes at the apex.
Conservation status. Microlicia xylopodifera has a restricted extent of occurrence (EOO = 80 km 2 ) and area of occupancy (AOO = 20 km 2 ) and, therefore, we recommend that it be considered Endangered [EN B1ab (ii, iii, iv] if all IUCN (2019) guide-lines are followed. So far, all populations of M. xylopodifera have been found inside the park boundaries, where we believe the species is protected.
Phenology. Flowers and fruits have been collected in March. Etymology. The specific epithet "xylopodifera" refers to the robust xylopodium (also described as lignotubers) present in all specimens examined. Xylopodium or lignotuber is an organ that buffers the plant against extremes of water loss, temporal mineral or nutritional deficiency, providing also protection against fire (Gottsberger and Silberbauer-Gottsberger 2006).
Additional specimens examined (

Discussion
Using the key to the species of Microlicia of the Chapada dos Veadeiros National Park proposed by Diniz and Silva (2019), M. gracilis and M. xylopodifera should be positioned close to M. latifolia D.O.Diniz & M.J.Silva since they have branch, leaf, hypanthium and sepal covered by setose trichomes and spherical glands, sessile and concolorous leaf blade, 2(-3)-veined, with serrate and ciliate margin, pedicellate flower, pink petal and stamens with bicolorous and polysporangiate anthers. Microlicia latifolia differs in having elliptic or ovate-elliptic leaf blade, apiculate at the apex, campanulate hypanthium, linear sepal, apiculate at the apex, glabrous petal and sub-isomorphic stamens with oblong anthers. Table 1 includes additional features comparing the species most similar to M. gracilis and M. xylopodifera.
Microlicia gracilis bears some resemblance to Microlicia xylopodifera in having sessile leaf with a lax arrangement on the branches, pedicellate flower (pedicel 0.7-1 mm long), urceolate hypanthium, dimorphic stamens with bicolorous and polysporangiate anthers. However, M. xylopodifera differs in having a cespitose habit, robust xylopodium and glandular trichomes covering branch, both leaf blade surfaces, hypanthium and sepal. Moreover, the apex of the flower bud is densely hairy-glandular, forming a crown at its apex and, during anthesis, the trichomes are concentrated at the apex of the petal. Microlicia gracilis resembles Microlicia ramosa Pilger, which is endemic to Goiás (Flora do Brasil 2020), for both species have branch, leaf, hypanthium and sepal covered with setose trichomes and spherical glands, sessile and ascending leaf blade, pedicellate flower, triangular sepal, magenta petal and dimorphic stamens with bicolorous and polysporangiate anthers. However, M. ramosa differs in having a typical branching pattern in which the branches have short secondary branches (Versiane et al. 2016), discolorous leaf (darker adaxial surface), ovate or ovate-lanceolate leaf blade with rounded or cordate base, longer pedicel (ca. 1 mm long) and the petal acute or retuse at the apex.
Microlicia xylopodifera is distinguished from other species of Microlicia by the presence of a robust xylopodium and a crown of glandular trichomes at the apex of the flower bud, which are concentrated at the apex of the petal. The new species is similar to M. ramosa Pilger in having sessile, discolorous and ovate or ovate-lanceolate leaves that are rounded or slightly cordate at the base, pedicellate flower, triangular sepal and dimorphic stamens with bicolorous, polysporangiate and ovate-oblong anthers. However, M. ramosa differs in having shorter secondary branches, 3-5-veined leaf and a vinaceous or greenish hypanthium often with vinaceous stains. Microlicia xylopodifera also resembles M. ordinata (Wurdack) Almeda & A.B.Martins, which is endemic to Goiás (Versiane et al. 2016;Machado and Romero 2020), in having branch, leaf, hypanthium and sepal covered with glandular trichomes and spherical glands, sessile and discolorous leaf, ovate-lanceolate leaf blades that are rounded or cordate at the base, triangular sepal and dimorphic stamens with bicolorous and polysporangiate anthers. However, M. ordinata has leaf with larger dimensions (5-20 × 2.5-13.5 mm), 3-5-veined, shorter pedicel (ca. 0.5 mm long) and petal with a single glandular trichome at the apex. In addition, the anther of the antesepalous stamen is yellow with orange stains. The new species bears some resemblance to M. vestita DC. which occurs in the Distrito Federal and States of Bahia, Minas Gerais, Goiás, Mato Grosso do Sul and Pará (Flora do Brasil 2020). Microlicia vestita also has setose trichomes and spherical glands on the branch, leaf, hypanthium and sepal, sessile leaf, ovate or ovate-lanceolate leaf blade with serrate and ciliate margin, triangular sepal and dimorphic stamens with bicolorous anthers. However, M. vestita differs in having imbricate leaf, denser indumentum covering the whole plant, campanulate hypanthium and tetrasporangiate anthers.