Eremitis clarkiae and E. vinacea (Poaceae, Bambusoideae): two new species of herbaceous bamboos endemic to the Atlantic Forest of southern Bahia, Brazil increase the diversity of the genus in this hotspot

Background and aims – We here describe two new species of Eremitis from Bahia, Brazil, and compare them with morphologically similar species. We also provide illustrations, photos, a distribution map, and notes on habitat and conservation status of the new species.Material and methods – This study was based on fieldwork, analysis of herbarium specimens, and literature review. Specimens collected were analyzed and photographed during fieldwork and observed in cultivation in a greenhouse. The conservation assessment is based on field observations and spatial analyses, following the IUCN guidelines and criteria.Results – Eremitis clarkiae sp. nov. occurs in southern Bahia and has been collected only twice, in the municipality of Floresta Azul. The new species is similar to E. jardimii and E. robusta, both also endemic to Bahia, but can be distinguished by several vegetative and reproductive structures longer than those observed in these species, such as leafy culms, ligules, decumbent culm inflorescences, and pedicels of the staminate spikelets of the staminate whorls. Eremitis vinacea sp. nov. was collected in three localities in southern Bahia, but only the type population was found during recent field trips, in the municipality of Camacã. It is similar to E. afimbriata, a species endemic to Espírito Santo state, being differentiated by its leaf sheaths with persistent fimbriae (vs absent), leaf blades with green adaxial surface (vs bluish green with a blue iridescence), and a single inflorescence on decumbent culms (vs multiple). Both new species are endemic to the Bahian Coastal Forests subregion and should be considered Critically Endangered (CR), according to the IUCN guidelines and criteria.

Integrated Genomic Analyses From Low-Depth Sequencing Help Resolve Phylogenetic Incongruence in the Bamboos (Poaceae: Bambusoideae)

The bamboos (Bambusoideae, Poaceae) comprise a major grass lineage with a complex evolutionary history involving ancient hybridization and allopolyploidy. About 1700 described species are classified into three tribes, Olyreae (herbaceous bamboos), Bambuseae (tropical woody bamboos), and Arundinarieae (temperate woody bamboos). Nuclear analyses strongly support monophyly of the woody tribes, whereas plastome analyses strongly support paraphyly, with Bambuseae sister to Olyreae. Our objectives were to clarify the origin(s) of the woody bamboo tribes and resolve the nuclear vs. plastid conflict using genomic tools. For the first time, plastid and nuclear genomic information from the same bamboo species were combined in a single study. We sampled 51 species of bamboos representing the three tribes, estimated their genome sizes and generated low-depth sample sequence data, from which plastomes were assembled and nuclear repeats were analyzed. The distribution of repeat families was found to agree with nuclear gene phylogenies, but also provides novel insights into nuclear evolutionary history. We infer two early, independent hybridization events, one between an Olyreae ancestor and a woody ancestor giving rise to the two Bambuseae lineages, and another between two woody ancestors giving rise to the Arundinarieae. Retention of the Olyreae plastome associated with differential dominance of nuclear genomes and subsequent diploidization in some lineages explains the paraphyly observed in plastome phylogenetic estimations. We confirm ancient hybridization and allopolyploidy in the origins of the extant woody bamboo lineages and propose biased fractionation and diploidization as important factors in their evolution.

Reinterpretation of Vegetative and Reproductive Characters Validates Three New Species in the Endangered Herbaceous Bamboo Genus Eremitis (Poaceae, Bambusoideae, Olyreae) from the Atlantic Forest, Brazil

Abstract— Reinterpreting the morphology of two taxa proposed by Victoria C. Hollowell in the 1980s and not formally published, we describe here three new species of Eremitis, a Neotropical genus of herbaceous bamboos (Poaceae, Bambusoideae, Olyreae), which is endemic to the Brazilian Atlantic Forest. Two of them, Eremitis grandiflora and E. paucifolia, are endemic to Espírito Santo state. Eremitis victoriae occurs in southern Espírito Santo and has also been documented for southern Bahia. Eremitis grandiflora is similar to the smallest species of the genus, but can be differentiated by its decumbent culms with scale-like leaf blades and its longer gynecandrous whorls. Eremitis paucifolia is characterized by its leafy culms with a reduced number of leaves [5‐6(‐7)] compared to other species of the genus. Eremitis victoriae is distinguished from the congeneric species mainly by its abaxially glaucous leaf blades. Here, we provide an identification key to all described species of Eremitis that occur in Espírito Santo, as well as a map with their geographical distribution. All three new species are illustrated with both line drawings and photographic images, and an informal assessment of their conservation status is presented.

Lectotypification of two names belonging to Olyra (Olyreae, Bambusoideae, Poaceae)

Olyra Linnaeus (1759: 238) is the best known genus of the herbaceous bamboos, belonging to the tribe Olyreae Kunth ex Spenner (1825: 172), which is composed of the subtribes Buergersiochloinae L.G.Clark & Judz. in Judziewicz & Clark (2007: 311), Parianinae Hackel (1887: 88) and Olyrinae Krombach (1875: 496) (Oliveira et al. 2014, Clark & Oliveira 2018, Ferreira et al. 2019, Oliveira et al. 2020a, Oliveira et al. 2020b). Olyra is the largest genus within the subtribe Olyrinae, including 25 species in its current delimitation, but this estimate will soon be revised since phylogenetic studies evidenced its non-monophyletic nature (Oliveira et al. 2014, Clark & Oliveira 2018, Oliveira et al. 2020a, Oliveira et al. 2020b). All species occur throughout the Neotropics, except O. latifolia Linnaeus (1759: 1261), which is also found in Africa/Madagascar and Sri Lanka (Judziewicz & Clark 2007, Ruiz-Sanchez et al. 2019).

Pariana caxiuanensis (Parianinae, Poaceae): a new species of an enigmatic genus of herbaceous bamboos from the Brazilian Amazon

Pariana caxiuanensis (Poaceae) is described and illustrated as a new species from the Brazilian Amazon. The new species is characterized by having the leaves clustered at the apex of the leafy culm, fimbriae few to absent, dimorphic flowering culms, large ligules (2.5–4 mm long), and pubescent to hirsute synflorescences. We present a morphological description, illustrations of the new species, the conservation status assessment, and a key to differentiate P. caxiuanensis from its morphologically related congeners.

Notes on leaf micromorphology of the rare herbaceous bamboo Buergersiochloa bambusoides Pilg. (Olyreae, Poaceae) from New Guinea and its taxonomic implications

We present notes on the leaf micromorphology of Buergersiochloa bambusoides, a rare species from New Guinea and included in Buergersiochloinae, one of three subtribes of the herbaceous bamboos (tribe Olyreae). We used scanning electron microscopy and light microscopy to analyze the microcharacters of both adaxial and abaxial leaf surfaces. Within the Olyreae, saddle-shaped silica bodies in both the costal and intercostal zones are considered unique to Buergersiochloinae. Simple, circular and very small papillae are observed on the adaxial surface, and for the first time, branched papillae on the abaxial surface are observed in B. bambusoides. On the abaxial surface, there are papillae on long cells associated with the stomatal complexes. Bicellular microhairs are the only trichomes present and they are found almost exclusively on the abaxial surface. The saddle-shaped silica bodies are the most taxonomically important among the microcharacters observed on the leaf surface of B. bambusoides.

Eremitis berbertii and E. fluminensis (Poaceae, Bambusoideae): New Species from the Brazilian Atlantic Forest and Updates on Leaf Microcharacters in the Genus

Eremitis Döll is a herbaceous bamboo genus (Poaceae, Bambusoideae, Olyreae) belonging to subtribe Parianinae that currently includes seven species. During fieldwork conducted throughout the geographic distribution of the genus, two new species with blue iridescent leaves, E. berbertii F. M. Ferreira & R. P. Oliveira and E. fluminensis F. M. Ferreira & R. P. Oliveira, from the Brazilian Atlantic forest, were collected and are here described and illustrated. Eremitis berbertii is endemic to the Private Reserve of Natural Heritage (Reserva Particular do Patrimônio Natural [RPPN]) Serra do Teimoso, in Bahia State, and E. fluminensis is restricted to the south of Rio de Janeiro State. In this study, micromorphological features of the leaf epidermis of the new species were compared with other species of the genus that display blue iridescence in their leaf blades. Variegated leaves are recorded for the first time in herbaceous bamboos. Comments on habitat, distribution, and conservation status of the new taxa are provided, as well as a revised identification key to all species of the genus described so far.

Leaf micromorphology in Poaceae subtribe Olyrinae (Bambusoideae) and its systematic implications

We analysed the leaf epidermal surfaces of 52 species of herbaceous bamboos belonging to all 20 genera of subtribe Olyrinae (Olyreae). We used scanning electron microscopy (SEM) and light microscopy (LM) to describe their foliar microcharacters and test the taxonomic utility of these characters in the subtribe. Shape and distribution of silica bodies, presence, type and distribution of papillae on the long cells and subsidiary cells and the presence and distribution of prickles and macrohairs were found to be taxonomically informative, whereas microhairs were not useful in this group. The type of papillae on the abaxial surface had a robust taxonomic value mainly at the generic level, whereas the distribution of these microstructures helped to differentiate some species of Arberella, Cryptochloa, Diandrolyra, Olyra, Piresia and Sucrea. We also confirmed that in some species, papillae associated with the stomata are on the long cells and project over the stomatal complexes, whereas in other species they occur on the subsidiary cells.

Delving deeper into the phylogenetics of the herbaceous bamboos (Poaceae, Bambusoideae, Olyreae): evaluation of generic boundaries within the Parodiolyra/Raddiella clade uncovers a new genus

The present study aims to expand the knowledge of phylogenetic relationships in Olyrinae, a subtribe of herbaceous bamboos (Poaceae: Bambusoideae: Olyreae). Our focus is on Parodiolyra and Raddiella, two historically related genera that, with their sister Diandrolyra, form one of the four main lineages in the subtribe. Previous phylogenetic analyses suggested that Parodiolyra is not monophyletic, but its taxonomic boundaries and its relationship with Raddiella remain uncertain due to low sampling. We increased the taxon sampling and sequenced five regions of the nuclear and plastid genomes for this lineage and other representatives of Olyreae. We used maximum parsimony, maximum likelihood, Bayesian inference and coalescence analysis. Our results corroborate the paraphyly of Parodiolyra, with P. micrantha sister to a clade including the remaining Parodiolyra and Raddiella. All remaining Parodiolyra form a well-supported clade, but Raddiella had conflicting resolutions, being either monophyletic or not. Thus, based on phylogenetic and morphological evidence, we here recircumscribe Parodiolyra, transferring P. micrantha and P. colombiensis to the new genus Taquara (described here). Regarding Raddiella, sampling is still not comprehensive and does not allow a decision on to its taxonomic status to be made at this time. Inclusion of other phreatophytic species may be crucial to resolve the problem of conflicting topologies.