The genus Brittonodoxa (Sematophyllaceae) in Brazil

Abstract This study presents an update on the occurrence of the genus Brittonodoxa in Brazil with diagnosis, taxonomic comments, illustrations, and geographical distribution data. We recognized three species from Brazil and the geographical distribution of two of them is being expanded: B. cataractae is being reported here for the first time the states of ES, RJ, and RS, and B. lithophila in the Amazon Forest and Pampa biome, occurring in the states of AM, ES, MA, MS, MT, PA, PR, RJ, RS, and TO.


Introduction
Brittonodoxa W.R. Buck, P.E.A.S. Câmara & Carv.-Silva is a genus of the family Sematophyllaceae, described by Carvalho-Silva et al. (2017).According to these authors, the name of the genus as given in homage to Elizabeth G. K. Britton, one of the first female bryologists in the world.The genus comprises species previously placed in Sematophyllum Mitt.or Rhaphidostegium (Schimp.)De Not.Molecular phylogenetic analyses resolved the taxonomic conflict and showed Brittonodoxa to be a monophyletic genus within the Sematophyllaceae crown clade (Carvalho-Silva et al. 2017).
According to Carvalho-Silva et al. (2017), most species of the Sematophyllaceae crown clade, including all species of the clades (e.g., Donnellia Austin, Jirivanaea U.B.Deshmukh & Rathor, and Pterogoniopsis Müll.Hal), can be recognized by the presence of alar cells of the Brotherelloid type and are restricted to the New World, except for the clades Brittonodoxa and "Rhaphydorrhynchium". Brittonodoxa is a tropical genus composed of six species distributed in Mexico, Central and South America, and West Indies, with some species in Africa (Carvalho-Silva et al. 2017).
Although, Brittonodoxa has low to moderate bootstrap support value, its species can be distinct using morphological characteristics (Carvalho-Silva et al. 2017).They are easily recognized by their ovate to ovate-lanceolate and concave leaves and, acute to short-acuminate, rhomboid to hexagonal cells (Evangelista-dos-Santos & Valente 2022a) and can be differentiated from the other genera of Sematophyllaceae (e.g., Donnellia and Meiothecium Mitt.) based on the morphological characteristics of the peristome.The morphology of the exostome and endostome is considered a good feature to distinguish the genera of this family.
Recent studies on species of Sematophyllaceae in Brazil have revealed novelties in the genus Brittonodoxa.Hence, in this study, we present
Descriptions, recognized synonyms, illustrations, comments, distribution in Brazil, substrate types, selected material, and maps are provided for each species.New occurrences are indicated by an asterisk (*).Distribution maps were prepared using ArcGis v.10.2, based on the geographic coordinates of the collections.All shapefiles and geographical information were obtained from the IBGE (Instituto Brasileiro de Geografia e Estatística 2022) database.

Results and Discussion
Brittonodoxa is represented in Brazil by three species: Brittonodoxa cataractae (W.R. Buck) W.R. Buck Brittonodoxa cataractae is being expanded in the Atlantic Forest biome (Fig. 1), and B. lithophila is reported for the first time from the Amazon Forest and Pampa biome (Fig. 1).Brittonodoxa subpinnata is widely distributed, in mesic to humid forests (Buck 1998) and in urban environments (Evangelista-dos-Santos et al. 2021), in Brazil, has a wide distribution (Fig. 1).

Taxonomic treatment
Key to Brittonodoxa species of Brazil  Brittonodoxa cataractae can be recognized by the shape of the leaves, the poorly developed alar cells and 1-2 rows of supra-alar cells, the bordered exostome, perforate endostome segments and single cilia.The records of the occurrence this species, which was known to occur only around the type locality, are being expanded with the present study.Studies like the present on can contribute to a better understanding of the distribution of this species.According to Buck (1983), B. cataractae is very similar to Sematophyllum cubense Buck, but, it can be distinguished the more ovate leaves with entire margins, the smaller alar cells, and endostome cilia.
Brittonodoxa cataractae is endemic of Brazil, distributed in the Atlantic Forest and Pampa biome.Here, we confirm the occurrence in the states of   Espírito Santo*, Rio de Janeiro*, Rio Grande do Sul*, and Santa Catarina.The species can be found in Ombrophilous forest, growing on decaying roots, trees, soil, or rocks at 250-1,339 m alt.

2.
Brittonodoxa lithophila (Hornsch.)W.R. Buck Brittonodoxa lithophila can be recognized by the orbicular to ovate shape of the leaves with mucronate or obtuse apices.Buck (1998) described the leaves of this species as broadly ovate and obtuse-mucronate with compact alar cells.Some leaves may have an acute apex, but the other essential characteristics do not change (Evangelista-dos-Santos et al. 2021).This species occurs preferentially close to rivers or on submerged rocks.Buck (1998) included Sematophyllum cochleatum (Broth.)Broth.as a heterotypic synonym of B. lithophila, but after analyzing the Isotypes deposited in New York Botanical Garden (NY01179097 and NY01179098) we do not consider them as a synonym.Sematophyllum cochleatum presents numerous, quadratic to short quadratic alar cells, in 4-5 rows.This species is more related to Rhaphidostegium amnigenum Broth., also considered a synonym of B. lithophila by Buck (1998), however recent phylogenetic analysis has transferred R. amnigenum to the genus Trichosteleum Mitt. (Carvalho-Silva et al. 2017).
Brittonodoxa lithophila is endemic of Brazil, distributed in the Amazon, Atlantic Forest, Cerrado and Pampa.Here, we confirm the occurrence in the states of Amazonas*, Bahia, Distrito Federal, Espírito Santo*, Maranhão*, Minas Gerais, Mato Grosso do Sul*, Mato Grosso*, Pará*, Paraná*, Rio de Janeiro*, Rio Grande do Sul, Santa Catarina, São Paulo and Tocantins*.The species can be found in rainforests, montane forests, and igarapés (side channels of rivers), growing on decaying roots, trees, soil, or rocks at 213-1,385 m alt.Brittonodoxa subpinnata presents a wide range of morphological variation, especially in the leaf shape, which has led to misidentifications.Because of this, a high number of heterotypic synonyms, approximately 209, were listed in Tropicos (2022, <https://tropicos.org/name/>), which need a revision.In the present work, we have included only a few of the names corresponding to those whose types we analyzed, on order to avoid excessive elaboration.