Increasing knowledge on the diversity of canelas-de- ema in the campo rupestre: two new species of Vellozia (Velloziaceae) from the southern Espinhaço Range, Brazil

Background and aims – Two new species of Vellozia (Velloziaceae) are here described and illustrated, Vellozia albohexandra and V. mellosilvae. These new species are morphologically similar to Vellozia armata, V. luteola, and V. inselbergae, probably belonging to the same informal group. Material and methods – Morphological and anatomical descriptions were based on herbarium specimens and in situ observations. Standard taxonomy and plant anatomy practices and methods were applied. Key results – Vellozia albohexandra can be easily distinguished from the other species of the group of V. luteola by its sessile flowers with white and smaller petals and sepals, six stamens, and smaller style and stigma. The species is endemic to the Cristália municipality, Minas Gerais state, and has been classified as Data Deficient according to IUCN criteria. Vellozia mellosilvae shares morphological affinities with V. armata, but it is distinguished by the leaves with serrate margin and abaxial furrows, longer and evident pedicel, and larger petals and sepals. This species is endemic to the Itacambira municipality, and should be considered Critically Endangered.


INTRODUCTION
Velloziaceae (Pandanales; APG IV 2016) is an amphitropical family composed of five genera (i.e. Acanthochlamys P.C.Kao, Barbacenia Vand., Barbaceniopsis L.B.Sm., Vellozia Vand., and Xerophyta Juss.) and approximately 250 species (Mello-Silva et al. 2011). Most of its diversity is found in the Neotropical region, especially in the Brazilian campo rupestre, where Velloziaceae is one of the most abundant and speciesrich group of vascular plants with about 200 species, of which 183 are endemic (e.g. Mello-Silva 1995;Conceição et al. 2007aConceição et al. , 2007b; Flora e Funga do Brasil 2021). Even with a high number of species recorded, its diversity is probably underestimated due to the difficulty of accessing some occurrence areas (e.g. Brazilian campo rupestre and Atlantic Forest inselbergs) and to the micro-endemism of many species (Mello-Silva and Menezes 1999).
Campo rupestre is a Brazilian ecosystem associated with high altitude areas, between 1,000 and 2,000 meters above sea level (Saadi 1995;Vasconcelos et al. 2020). This ecosystem is mainly distributed in the Espinhaço Range and Chapada dos Veadeiros in Central/Eastern Brazil, and its vegetation is composed by shrubs and herbs associated to rock outcrops and sandy soils (Vasconcelos 2011;Alves et al. 2014). Campo rupestre is exceptional due to its rich and highly endemic flora   (Cabral et al. 2021), are probably related to an informal group composed by Vellozia armata Mello-Silva and V. luteola Mello-Silva & N.L.Menezes, due to their morphological similarity (Renato Mello-Silva pers. comm.). This group was characterized by leaf blades persistent, involute, and amphystomatic, with smooth subsidiary cells, pedicel with nine fibro-vascular bundles and circular in cross section, outer integument of empty cells vanishing in the seeds in a previous cladistic analyses (Mello-Silva 2005).
The results of this article are part of a broad project on the systematics of Vellozia luteola group, led by Renato Mello-Silva, who suddenly passed away before he could finish it. The specific epithet of Vellozia albohexandra was chosen by Renato Mello-Silva and with V. mellosilvae, we formalized a tribute to his memory. Renato Mello-Silva (1961 was an outstanding Brazilian botanist who dedicated decades to the study of the phylogeny and taxonomy of Annonaceae and Velloziaceae and made substantial contributions to the knowledge of the Brazilian biodiversity, especially of the campo rupestre.

Vellozia mellosilvae
Distribution and habitat. Vellozia mellosilvae occurs in the campo rupestre of Itacambira municipality, southern Espinhaço Range, Minas Gerais state, Brazil (Fig. 3). This species is found in rocky outcrops among shrubs in sandy soil and rock crevices at elevations from 1,200 to 1,280 m. Phenology. Flowering in December and fruiting from January to February. Etymology. The epithet is named after Renato Mello-Silva (1961, the greatest authority in the systematics of Brazilian Velloziaceae and who also collected the holotype of Vellozia mellosilvae. Preliminary IUCN Conservation assessment. Vellozia mellosilvae is endemic to the municipality of Itacambira and has an area of occupancy of 12 km² and extent of occurrence of approximately 11 km². Although it occurs in large populations, V. mellosilvae is not protected by conservation units. Besides that, the campo rupestre is a sensitive ecosystem to threats such as mining and livestock farming (Ribeiro and Freitas 2010). Therefore, V. mellosilvae is considered Critically Endangered: CR B1abiii. Notes. Vellozia mellosilvae morphotype was already described under Vellozia luteola in Mello-Silva and Menezes (1988) based on vegetative characters and fruit morphology. However, the author observed conspicuous differences in the leaf anatomy between populations from the type-location of V. luteola and from Itacambira (i.e. presence/absence of bulliform cells and abaxial furrows). After analysing a recent collection of a flowering individual, we recognized the population of Itacambira as a distinct species. In addition to the characters highlighted by Mello-Silva (1988), V. mellosilvae can be differentiated from V. luteola by the violet perianth (vs yellow in V. luteola), sepal and petal dimensions (2.5-4.2 cm × 9-12.7 mm vs 1.5-2.5 cm × 4-7 mm in V. luteola) and presence and distribution of emergences on their abaxial surface, 18-20 stamens (vs 15 in V. luteola), anthers length (6-11 mm vs 4-7 mm in V. luteola), and stigma diameter (2.4-4 mm vs ca 6 mm in V. luteola) (Table 1).

DISCUSSION
Besides the broad studies on the systematics of Velloziaceae (e.g. Smith 1962;Smith and Ayensu 1976), knowledge on the diversity of the family has gradually increased thanks to the taxonomic efforts focused on small clades or informal groups (e.g. Mello-Silva and Sasaki 2016; Mello-Silva and Cabral 2022), populations (e.g. Mello-Silva 2010), or a given area (e.g. Montserrat and Mello-Silva 2013). In this way, several new taxa have been described in Velloziaceae nowadays (e.g. Cabral et al. 2021;Mello-Silva and Cabral 2022;present study), although its diversity may be still underestimated (see Introduction).
The Vellozia luteola group is one of the several informal groups in Velloziaceae recognized in the first complete cladistic analyses of the family (Mello-Silva 2005). Although the species belonging to this group share morphological and anatomical characters (see Introduction), a phylogenetic inference including macromolecular evidence and a complete species sampling has not been performed so far. All these species, except by V. inselbergae, occur in the campo rupestre, southern Espinhaço Range, Cerrado domain. Vellozia inselbergae is the only species of the V. luteola group occurring in the inselbergs of the Atlantic Forest domain (Cabral et al. 2021).
Both campo rupestre and Atlantic Forest inselbergs have been under numerous threats, such as mining, livestock farming, tourism, road construction, and urbanisation (Porembski et al. 2016;Fernandes et al. 2020), and there is a risk that these environments will suffer great loss in their biodiversity and ecosystem services before we can fully understand them. For this reason, describing the diversity and investigating the systematics of an important element of these environments, such as Velloziaceae (Conceição et al. 2007a(Conceição et al. , 2007b, is an important step towards their conservation.