Liana attachment to supports leads to profound changes in xylem anatomy and transcriptional profile of cambium and differentiating xylem.

Wood serves crucial functions in plants, yet our understanding of the mechanisms governing the composition, arrangement, and dimensions of its cells remains limited. The abrupt transition from nonlianescent to lianescent xylem in lianas represents an excellent model to address the underlying mechanisms, although consistent triggering factors for this process remain uncertain. In this study we examined how physical support attachment impacts the development of lianescent xylem in Bignonia magnifica (Bignoniaceae), employing a comprehensive approach integrating detailed anatomical analysis with gene expression profiling of cambium and differentiating xylem. Our findings demonstrate that attachment to physical supports triggers the formation of lianescent xylem, leading to increased vessel size, broader vessel distribution, reduced fibre content, and higher potential specific water conductivity than nonlianescent xylem. These shifts in wood anatomy coincide with the downregulation of genes associated with cell division and cell wall biosynthesis, and the upregulation of transcription factors, defense/cell death, and hormone-responsive genes in the lianescent xylem. Our findings provide insights into the regulation of xylem differentiation, driven by response to environmental stimuli. Additionally, they shed light on the mechanisms underlying the adaptation of lianas to climbing.

A new species of Schlegelia (Schlegeliaceae) from wet montane forest of Colombia and a key for the species of the genus.

In this paper we describe and illustrate Schlegelialongirachis a new species from montane forest remnants (1200--1900 m) in the Western slope of the Eastern Cordillera of Colombia ("Serranía de Las Quinchas" and Virolín county) in the Departments of Boyacá and Santander. A root-climbing liana, the new species is contrasted to S.fuscata, S.monachinoi and S.parviflora, the three most morphologically similar species of Schlegelia. This new species is differentiated from its putative close relatives by vegetative (texture, colour, pubescence and shape in leaves, bracts, bracteoles pedicel, calyx and corolla), inflorescences as well as floral characters (staminode absent). We provide an updated key to 24 known species of Schlegelia. For the identification key, S.fuscata and S.roseiflora are regarded here as different from S.parviflora. S.urbaniana is considered a synonym of S.axillaris, whereas S.fastigiata is separated from S.sulphurea as a recognizable species. Schlegelia has its center of distribution in Colombia, where 17 of the species are known to occur.

ResumenEn este artículo se describe e ilustra Schlegelialongirachis una nueva especie de los remanentes de bosques montanos húmedos (1200--1900 m) localizados en la vertiente occidental de la Cordillera Oriental de Colombia, en la Serranía de Las Quinchas y corregimiento de Virolín, en los departamentos de Boyacá y Santander (respectivamente). Esta nueva especie es una liana trepadora por raíces, la cual comparte varias similaridades con S.fuscata, S.monachinoi y S.parviflora. Sin embargo, difiere de estas especies en la textura, colores, pubescencia, forma de las hojas, brácteas, bractéolas, pedicelo, cáliz y corola, en el tipo de inflorescencia y por la ausencia del estaminodio. Se presenta una clave actualizada para diferenciar las especies del género Schlegelia. Para la clave, en un contexto geográfico y taxonómico, S.fuscata y S.roseiflora son tratadas como especies diferentes de S.parviflora. Por otra parte, S.urbaniana es considerada un sinónimo de S.axillaris y S.fastigiata es separada de S.sulphurea, y es reconocida como una especie válida. La presente contribución incrementa a 24 las especies de Schlegelia, 17 de éstas se conocen en Colombia, el país con la mayor diversidad del género.

Climbing mechanisms and the diversification of neotropical climbing plants across time and space.

Climbers germinate on the ground but need external support to sustain their stems, which are maintained attached to supports through modified organs, that is, climbing mechanisms. Specialized climbing mechanisms have been linked to higher diversification rates. Also, different mechanisms may have different support diameter restrictions, which might influence climbers' spatial distribution. We test these assumptions by linking climbing mechanisms to the spatiotemporal diversification of neotropical climbers. A dataset of climbing mechanisms is presented for 9071 species. WCVP was used to standardize species names, map geographical distributions, and estimate diversification rates of lineages with different mechanisms. Twiners appear concentrated in the Dry Diagonal of South America and climbers with adhesive roots in the Chocó region and Central America. However, climbing mechanisms do not significantly influence the distribution of neotropical climbers. Also, we found no strong support for correlations between specialized climbing mechanisms and higher diversification rates. Climbing mechanisms do not strongly impact the spatiotemporal diversification of neotropical climbers on a macroevolutionary scale. We argue that the climbing habit is a synnovation, meaning the spatiotemporal diversification it promotes is due to the sum effect of all the habit's traits rather than isolated traits, such as climbing mechanisms.

Paullinieae (Sapindaceae) of the restingas of Rio de Janeiro, Brazil: taxonomy and distribution / Paullinieae (Sapindaceae) das restingas do estado do Rio de Janeiro, Brasil: taxonomia e distribuição

Abstract Paullinieae is a predominantly neotropical tribe comprising six genera (Cardiospermum, Lophostigma, Paullinia, Serjania, Thinouia and Urvillea), of which Lophostigma is the only one not found in Brazil. This study was conducted in the sandy coastal plains (restingas) of Rio de Janeiro state, which from the mouth of the Itabapoana river in the north, bordering Espírito Santo state, to Ponta da Trindade (including Ilha Grande) in the south, bordering São Paulo state. This ecosystem has great biodiversity, but has been constantly threatened by deforestation, human occupation and degradation resulting from tourism. In this area we found 30 species in five genera: Cardiospermum (1 sp.), Paullinia (9 spp.), Serjania (15), Thinouia (2) and Urvillea (3). The taxonomic treatment includes a key to identify the taxa, and for each species a morphological description, illustrations, a map of its geographical distribution, ecological information, phenological data, and conservation status. Most species occurred in ridge forests, followed by dune thicket and non-flooded scrub formations. Among of the 30 species, four (Paullinia coriacea, P. ternata, Serjania fluminensis and S. littoralis) were recorded only in the sandy coastal plains, and four are endemic to Rio de Janeiro state (Serjania eucardia, S. fluminensis, S. littoralis and S. tenuis). In addition, four species are already included in the Red List of Brazilian Flora and another three are indicated in this study as threatened. This research is important not only to improve knowledge of Paullinieae species found in Rio de Janeiro's sandy coastal plains, but also to provide information to be used for conservation measures in the State, as well as in other coastal plains of Brazil.

Resumo Paullinieae é uma tribo predominantemente neotropical e compreende seis gêneros (Cardiospermum, Lophostigma, Paullinia, Serjania, Thinouia e Urvillea), dos quais Lophostigma é o único gênero não encontrado no Brasil. Este estudo foi conduzido nas restingas do estado do Rio de Janeiro, que começam na foz do rio Itabapoana, na fronteira com o estado do Espírito Santo e se estende até a Ponta da Trindade (incluindo a Ilha Grande), próximo à fronteira com o estado de São Paulo. Este ecossistema possui grande biodiversidade, mas tem sido constantemente ameaçado pelo desmatamento, ocupação humana e ações de degradação decorrentes do turismo. Nesta área foram encontradas 30 espécies pertencentes a cinco gêneros: Cardiospermum (1 spp), Paullinia (9 spp), Serjania (15), Thinouia (2) e Urvillea (3). O tratamento taxonômico incluiu descrição e chave para identificação das espécies, informações sobre as formações vegetacionais das restingas onde cada táxon ocorre, além de ilustrações e mapas de distribuição geográfica das espécies. A maioria das espécies ocorre em floresta de cordão arenoso, seguidas das espécies de vegetação arbustiva fechada de cordão arenoso e arbustiva aberta não inundável. Entre as 30 espécies, quatro delas (P. coriacea, P. ternata, S. fluminensis e S. littoralis) são encontradas apenas nas formações de restinga e quatro espécies são endêmicas do Rio de Janeiro (S. eucardia, S. fluminensis, S. littoralis e S. tenuis). Além disso, quatro espécies já estão incluídas na Lista Vermelha da Flora do Brasil e outras três estão indicadas neste estudo. Este trabalho é importante não apenas para melhorar o conhecimento das espécies de Paullinieae encontradas nas restingas do Rio de Janeiro, mas também para fornecer informações a serem utilizadas em medidas de conservação no Estado e nas demais regiões de restinga do Brasil.

Ontogeny, anatomical structure and function of lobed stems in the evolution of the climbing growth form in Malvaceae (Byttneria Loefl.).

BACKGROUND AND AIMS: Byttneria is one of the few climbing genera in Malvaceae. Some Byttneria are known for their lobed stems. We explore the development of these stems, how they have evolved within the group and their relevance in the evolution of the climbing growth form in Malvaceae. METHODS: We combine developmental anatomical work with phylogenetic comparative methods. We use Byttneria divaricata and B. filipes as models in the anatomical work, a review of herbarium vouchers, and the most recent phylogeny of Byttneria and allies to elucidate how these stems evolved within the clade under maximum-likelihood and Bayesian approaches. We use Pagel94 tests to analyse the correlated evolution of lobed stems and prickles. KEY RESULTS: Each lobe coincides with one of the five vascular bundles. By augmented activity of the fascicular cambium in the lobes coupled with reduced activity of the interfascicular cambium in the interlobes, secondary growth increases the lobulation already present during primary growth. Within Byttneria and allies, lobed young stems appeared at least three times, once in Ayenia and twice in the paraphyletic Byttneria. Lobed adult stems were conserved in Byttneria s.s., where lobed adult stems in combination with prickles were shown to have evolved as a climbing mechanism within the group; prickles were lost once within Byttneria s.s., in a shrubby subclade. Byttneria Clade 2 comprises climbers with twining cylindrical adult stems and no prickles, which constitutes a different climbing mechanism in the group. CONCLUSIONS: We provide evidence of one of the few cambial variants known whose secondary body reflects the primary body vasculature and show that lobed adult stems and prickles in Byttneria could be used in the new delimitation of genera in the group. Lobed stems independently appeared in climbing Grewia, suggesting a convergence favouring the climbing growth form.

Spatio-temporal evolution of climbing habit in the Dahlia-Hidalgoa group (Coreopsidae, Asteraceae).

In this paper we focus on Hidalgoa, a small genus distributed in cloud forest from Mexico to Colombia with the uncommon climbing habit of enlarging its petioles. This genus belongs to tribe Coreopsideae (Asteraceae), a group mostly from the Neotropics with a few taxa in Oceania and Polynesia. The phylogenetic position of Hidalgoa has not yet been determined though it will most probably be closely related to Dahlia. The aim of this paper is to understand the ecological and evolutionary consequences of the shift to a climbing growth form using a spatio-temporal approach to phylogenetic analyses, and by testing evolutionary models for ecological niche. Our results identified that Hidalgoa formed a sub- clade in a grade with Dahlia, with divergence occurring in the Pliocene. The ancestral life form for this clade was cryptophytic (e.g. geophytes). Analyses using the climate variables most important to the elements of the Dahlia-Hidalgoa clade indicate that they share the same preferences. Moreover, visualization by traitgrams of the significant climate variables shows no departure among clades. These results suggest that no evolutionary or ecological consequences have yet manifested, and that Hidalgoa can be considered a climbing Dahlia.

Climbing plants of Porto Ferreira State Park, southeastern Brazil / Trepadeiras do Parque Estadual de Porto Ferreira, Brasil

Abstract A floristic survey of climbing plants was carried out in an ecotone area of seasonal semideciduous forest (SSF) and forested savanna (CER), in Porto Ferreira State Park (PFSP), Southeastern Brazil. We sampled the reproductive specimens every month during two periods, March 2010 to September 2011 and April and July 2015. The surveys were performed by the walking method, and the sampled individuals were classified by habit, climbing mechanism and dispersal mode. Overall, 109 species, belonging to 67 genera and 29 families, were recorded; 49 species occurred in both, 29 and 31 were exclusive to SSF and CER, respectively. Bignoniaceae and Malpighiaceae were the richest families, with 17 species, followed by Sapindaceae (12 species), Asteraceae and Apocynaceae (8 species each) and Fabaceae (6). The majority of climbers were lianas, twining and anemochoric species, corresponding to 70%, 47% and 66% of all samples, respectively. In this work, we added one new family and 14 species to the Cerrado's list of climbing plants from São Paulo state, and 10 species to the Brazilian seasonal semideciduous forest's list. Therefore, we contributed to the understanding of diversity of climbing plants in vegetation types poorly studied for this plant group, mainly in the Cerradão, wherein we found new records for several species.

Resumo O levantamento florístico das trepadeiras foi realizado em um ecótono de Floresta Estacional Semidecidual (FES) e Cerradão (CER), no Parque Estadual de Porto Ferreira, Sudeste do Brasil. Realizamos coletas mensais dos espécimes reprodutivos ao longo de dois períodos, março 2010 a setembro 2011, abril e julho 2015. Os levantamentos foram realizados por meio do método de caminhada e os indivíduos amostrados foram classificados quanto ao hábito, mecanismo de ascensão e síndrome de dispersão. No geral, foram registradas 109 espécies, pertencentes a 67 gêneros e 29 famílias. Dentre essas, 49 espécies ocorrem nos dois tipos de vegetação, sendo que 29 e 31 espécies são exclusivas de FES e CER, respectivamente. Bignoniaceae e Malpighiaceae foram as famílias mais ricas com 17 espécies, seguidas por Sapindaceae (12 espécies), Asteraceae e Apocynaceae (8 espécies cada) e Fabaceae (6). A maioria das espécies de trepadeiras são lianas, volúveis e anemocóricas, correspondendo a 70%, 47% e 66% de toda a amostra, respectivamente. Neste trabalho, acrescentamos uma nova família e 14 espécies para a lista de trepadeiras do Cerrado paulista e 10 espécies para a lista brasileira de trepadeiras em Floresta Estacional Semidecidual. Portanto, contribuímos para o conhecimento da diversidade de trepadeiras em tipos vegetacionais pouco estudados para este grupo de planta, destacando o Cerradão, no qual encontramos novos registros para um grande número de espécies.

A liana from the lower Miocene of Panama and the fossil record of Connaraceae.

PREMISE OF THE STUDY: Permineralized wood is common in the Miocene beds exposed during the expansion of the Panama Canal. We describe a stem with the distinctive anatomy of a liana and evaluate the evolutionary, biogeographic, and ecological significance of this discovery. METHODS: The object of the study was obtained from a collection of fossil woods and fruits from a locality in the lower Miocene Cucaracha Formation, where the formation is exposed by the Culebra Cut of the Panama Canal. Thin sections were prepared using the cellulose acetate peel technique and examined using transmitted light microscopy. We described the anatomy and compared it with that of extant and fossil species. We also reviewed and evaluated published reports of fossils attributed to Connaraceae. KEY RESULTS: The anatomy of this fossil wood matches the genus Rourea (Connaraceae). The stem is only 1 cm in diameter, but vessels >200 µm in diameter also occur, indicating the perennial climbing habit. We evaluated 12 other pre-Quaternary occurrences attributed to Connaraceae. Four are accepted, three are rejected, and we consider five unknown or uncertain. CONCLUSIONS: The discovery of this Rourea stem confirms the presence of Connaraceae in the Neotropics by the early Miocene, provides the oldest evidence of the climbing habit in the family, and contributes to our understanding of the flora of Panama 19 mya. Although the fossil record of Connaraceae is sparse, reliable occurrences span three continents and indicate that the family originated as early as the Late Cretaceous-Paleocene and was widespread by the early Miocene.

The behavioural ecology of climbing plants.

Climbing plants require an external support to grow vertically and enhance light acquisition. Vines that find a suitable support have greater performance and fitness than those that remain prostrate. Therefore, the location of a suitable support is a key process in the life history of climbing plants. Numerous studies on climbing plant behaviour have elucidated mechanistic details of support searching and attachment. Far fewer studies have addressed the ecological significance of support-finding behaviour and the factors that affect it. Without this knowledge, little progress can be made in the understanding of the evolution of support-finding behaviour in climbers. Here I review studies addressing ecological causes and consequences of support finding and use by climbing plants. I also propose the use of behavioural ecology theoretical frameworks to study climbing plant behaviour. I show how host tree attributes may determine the probability of successful colonization for the different types of climbers, and examine the evidence of environmental and genetic control of circumnutation behaviour and phenotypic responses to support availability. Cases of oriented vine growth towards supports are highlighted. I discuss functional responses of vines to the interplay between herbivory and support availability under different abiotic environments, illustrating with one study case how results comply with a theoretical framework of behavioural ecology originally conceived for animals. I conclude stressing that climbing plants are suitable study subjects for the application of behavioural-ecological theory. Further research under this framework should aim at characterizing the different stages of the support-finding process in terms of their fit with the different climbing modes and environmental settings. In particular, cost-benefit analysis of climbing plant behaviour should be helpful to infer the selective pressures that have operated to shape current climber ecological communities.