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Approximately 10 % of vascular plants can grow as epiphytes, but the impact of epiphytism is more remarkable because there is an unknown percentage of re-terrestrialized taxa that evolved from epiphytic ancestors. Two main hypotheses have been proposed to explain the evolution of epiphytes: one suggests that they evolved from humid, umbrophilous environments (i.e., forest understory; Schimper hypothesis), and the other that they came from an open-infertile environment (Tietze-Pittendrigh hypothesis). The core evidence supporting these hypotheses is the frequency of terrestrial plants that accidentally grow as epiphytes (i.e., accidental epiphytes), because these plants should be abundant in the habitats that promote the colonization of the canopy by the terrestrial plants (i.e., the early state of epiphyte evolution). In a landscape with both environments (humid and umbrophilous vs. open and infertile), we tested the affinity of the flora to the epiphytic habitat and the association of the accidental epiphytes with each environment. We found 71 plant species. Forty-one percent were terrestrial; among the rest, 39 %, 3 %, and 17 % were accidental, facultative (growing equally as terrestrial or arboreal), and true epiphytes (preferentially living as arboreal), respectively. Discounting plants that exclusively grow terrestrially in the sample, in this landscape, a large proportion of the species living in tree crowns are accidental epiphytes (28), and 16 species belong to Asteranae and Rosanae, superorders where epiphytism is infrequent. Nine accidental epiphytes were associated with the open environment and none with the forest, supporting only the Tietze-Pittendrigh hypothesis. Our results support the idea that species from open environments could be preadapted to grow as epiphytes, and landscapes combining forested areas with open environments (e.g., xerophytic scrub, savanna) could promote the colonization of the canopies from terrestrial plants.

Plant phylogeny, diversity, and production of germination inhibiting chemicals can be used as patterns for inferring key drivers of plant community construction and assembly. We conducted the study in a restoration area of Atlantic Rainforest from Southeast Brazil. In this context, we aimed to investigate community assembly rules by simultaneously evaluating the relationships of species with a phylogenetic, functional, and ecophysiological (allelopathy) approach and multifaceted β diversity (taxonomic, phylogenetic, and functional). We measured the plant canopy height and diameter at soil height for all individuals and determined successional group and dispersal syndrome for all species regenerating in open areas and below 18 adult individuals of each tree species Bixa atlantica Antar & Sano, Inga laurina (Sw.) Willd., Joannesia princeps Vell. and Senna multijuga subsp. multijuga var. verrucosa (Vogel) H.S.Irwin & Barneby. Phylogenetic and functional indexes of community structure were calculated with the net relatedness index and the nearest taxon index. Taxonomic, phylogenetic, and functional diversities (respectively, TD, PD, and FD) for the regenerating community in each area were calculated and pairwise comparisons were made for TD, FD, and PD components of β diversity. Tests of tree species allelopathy derived from leaf extract were performed with seeds of Lactuca sativa L. (Asteraceae). The effects of diversity and extracts on seed germination were analyzed using generalized linear models. The phylogenetic and functional structure of the regenerating communities under the four tree species did not differ from random for the four studied tree species. The PD was significantly higher for the communities that regenerated under Joannesia, while the FD was higher under both Joannesia and Senna, compared to communities from open sites, evidencing a facilitation mechanism for these two species. Only Senna and Inga differed from random in relation to β TD and β FD, suggesting possible environmental changes in these areas. Seeds irrigated with the extracts of Inga, Joannesia, and Senna inhibited germination in an intermediate way, whereas seeds irrigated with Bixa extract had only 1 % germination, indicating allelopathic effects. In this way, the planted species directly influence the organization of communities that regenerate below their canopies. It is therefore important to choose species that can contribute to improving diversity, and thus favor the success of restoration projects.

Vatica cauliflora P.S.Ashton (Dipterocarpaceae) is an endemic and critically endangered tree found only in Kapuas Hulu, West Kalimantan, Indonesia. Due to a lack of fruiting specimens, the species has not been placed within one of the three sections currently recognised in the genus Vatica. In early 2020, this plant was recollected after 67 years. Voucher specimens were made of fruiting material, which enable us to assign this species to the correct section. Based on the equal, woody, and non-incrassate calyx lobes, the species is here placed in the sect. Vatica as these traits are shared with other species in that section. An updated morphological description alongside information on the habitat, vernacular names, and germination of the species are provided.

Wild-type pollen cones in Podocarpaceae are simple and “flower”-like, consisting of numerous non-axillary, hyposporangiate microsporangiophores. Teratological pollen cones of Nageia fleuryi are investigated here. One of the most striking and frequent forms is a compound “inflorescence”-like structure, consisting of numerous lateral pollen cones, here analogised with flowers. Each lateral pollen cone is inserted in the axil of a subtending leaf (pherophyll) and consists of several hyposporangiate microsporangiophores. Thus, the branching pattern in the teratological pollen cones corresponds strictly to the general branching pattern of seed plants. In the context of abnormal microsporangiophores that were previously documented for other coniferous groups, and the evolutionary transition series previously suggested for male reproductive structures in Taxaceae s.l., it seems highly likely that the simple, “flower”-like pollen cones of today´s podocarps are derived from a compound “inflorescence”-like ancestral condition by a simple reduction of lateral pollen cones (flowers) to just a single hyposporangiate microsporangiophore and the loss of all pherophylls within the pollen cone.

Spathe movements and spathe senescence mechanics observed during the pistillate and staminate anthesis phases are described in the genera Aridarum, Burttianthus, Hera, Heteroaridarum, Pursegloveia, Naiadia, Tawaia, and Toga. Floral scents and the originating reproductive structures are described and determined, in particular motility of the staminodes and distribution of stomata on the stamen and appendix.

The characteristics of topsoil phytolith assemblages can reflect the local vegetation and climatic conditions. We collected 53 topsoil samples along an isotherm corresponding to a mean annual temperature (MAT) of 4 °C in Northeast China, 20 samples were from the Daxing'an Mountains (DXAM), 18 samples from the Songnen Plain (SNP), and 15 samples from the Changbai Mountains (CBM). The phytoliths were classified into 13 morphological categories. We observed significant differences between the phytoliths assemblages from the DXAM, SNP, and CBM, and they could be statistically discriminated with a total accuracy of 81.1 %. ELONGATE percentages were more sensitive to MAT than to mean annual precipitation (MAP). There was a significant positive correlation between the percentages of ELONGATE, PTERIDOPHYTE-TYPE, PAPILLATE and MAP; and a significant negative correlation between the percentages of BILOBATE and MAP. We constructed a phytolith index (D/W) based on the common phytolith types, which reflects changes in environmental humidity: D/W = BILOBATE / (BILOBATE + ELONGATE); the higher the value of D/W the drier the environment, and vice versa. In Northeast China, D/W varied from 0.0 to 0.6, with the average of 0.3. D/W < 0.3 corresponded to a relatively humid climate, and D/W > 0.3 corresponded to a relatively dry climate.

The temperature and moisture requirements for reproduction (i.e. seed production and germination) underpin the biogeographical relationships between climate, distribution and population dynamics of plants, particularly narrow range endemic species. We aimed to investigate reproductive outputs and the responses of seeds to temperature and moisture availability across three Banksia arborea populations that are distributed over a narrow range (< 200 km²) of semi-arid habitat on banded ironstone formations of Western Australia. We conducted reproductive trait assessments by quantifying follicles per cone, proportion of viable seed and associated seed mass followed by hydrothermal germination assessments for each population to characterise temperature and water stress tolerance. We found the southern-most population, that receives marginally higher rainfall, had heavier seeds (10 ± 0.02 mg), a cooler optimum temperature (16.1 °C) and wider germination capacity under water stress at 10 °C and 15 °C (Ψ_b50 = -0.66 to -0.87 MPa) compared to the two northern populations (Ψ_b50 = -0.60 to -0.65 MPa). By contrast, both northern populations had slightly warmer optimum temperatures for germination (16.9–17.5 °C) and a higher capacity to germinate under water stress at warmer temperatures of 22.5 °C (Ψ_b50 = -0.43 to -0.56 MPa, compared to -0.29 MPa). Our work highlights that, even within the specific requirements of a narrow range endemic, different populations adapt to marginally different temperature and water stress tolerances. Warming of the southern populations could impact on future recruitment, and conservation action to promote resilient ecosystems are suggested.

Most Psittacanthus (Loranthaceae) mistletoes depend on frugivorous birds for seed dispersal, and the behaviour of seed dispersers strongly influences their spatial distribution. However, the timing of seed germination stages remains poorly studied. In this study, ripe fruits from nine Psittacanthus species, inhabiting contrasting habitats and host tree species, were collected for seed germination experiments, in which ripe fruits had their exocarp manually removed, and squashed seeds were placed and glued with their viscin on wooden rectangle sticks and daily monitored for 150 d under common environmental conditions. The germination process from seed attachment involved stages such as drying of the viscin, seed coat breaking, cotyledon expansion, and production of sticky latex-like exudates. Notably, the breakdown of the seed coat and cotyledon number varied among species. Breakdown of the seed coat did not occur in some species at least until the day the experiment ended (P. sonorae and P. auriculatus) and cotyledon number ranged from two to eight, with highest cotyledon count to date recorded for P. schiedeanus. Germination indices differed among species, with P. schiedeanus exhibiting higher values for germination rate and synchrony. A strong phylogenetic signal was found in fruit length, fruit width and cotyledon number. After accounting for phylogeny, cotyledon number was negatively associated with mean germination time and germination uncertainty, and positively associated with mean germination rate and germination speed coefficient. The other germination indices were not significantly associated with fruit or seed morphological traits or altitude. Interspecific variation in cotyledon number, seed coat characteristics, and in the timing and duration of seed germination stages highlights distinct processes, likely influenced by environmental differences. These findings highlight species-specific germination processes, the impact of cotyledon number on germination speed, and the potential evolutionary significance of specific morphological traits among Psittacanthus species.

The limited geographic distribution of endemic species renders them more susceptible to extinction risks stemming from a myriad of factors. One such factor could be meiotic constraints, which may directly or indirectly impact the reproductive success of the endemic plant species. Thus, comprehensive research on meiotic behaviour is essential for implementing species conservation measures. This study represents the first report on the male meiotic behaviour of Artemisia amygdalina Decne., a critically endangered endemic medicinal plant species of the Kashmir Himalaya. We procured the plant material from three different locations in the Kashmir Himalaya, and the chromosome number of the species from all sites was found to be 2n=18 (x = 9, n = 9), indicating its diploid nature. Various types of chromosomal abnormalities were found in these populations, including stickiness, univalents, out-of-plate bivalents, laggards, bridges, disturbed telophase, micronuclei, abnormal pollen grains formation and seed set formation. The overall percentage of chromosomal abnormalities varied among the populations, from 8.58 % to 25.16 %. Pollen sterility also varied among different populations, with maximum pollen sterility of 23.21 % and a minimum of 5.96 % across populations. The present findings will not only help in updating the chromosome atlas with the addition of a new report on chromosome number but also contribute to the understanding of the reproductive success of A. amygdalina. Further ecological and reproductive studies can facilitate the creation of effective management and conservation strategies for this species.

The encroachment of woody species has been affecting wetlands in the Cerrado biome, Brazil. This process has resulted in changes in plant diversity, soil physicochemical properties, and water availability. This study assessed changes in the taxonomic and functional diversity of plants and soil in Veredas wetlands in process of reduction in water availability and woody plant encroachment. Over a 14-year interval, we quantified taxonomic and plant functional diversity, soil physicochemical properties, groundwater depth, and its relationship with historical soil moisture using remote sensing in veredas. We investigated the effect of increased groundwater depth, woody vegetation cover, and changes in soil properties on species cover and richness. We observed a five to seven-fold increase in woody vegetation cover, accompanied by an increased in the richness of woody species from 21.4 % to 28.9 %. Nevertheless, this was counterbalanced by a 15.8 % to 35.2 % reduction in overall species richness and taxonomic diversity. At the same time, functional diversity decreased, leading to a community with more acquisitive traits. Groundwater depth increased from 20 to 60 cm. Soil properties changed, especially organic matter content, which increased two to 14 times. Changes in species richness and cover were related to increased organic matter and groundwater depth. The surveyed veredas exhibited considerable changes in plant species richness, soil, and hydrological properties, as well as woody vegetation cover, over 14 years. The veredas formed distinct functional composition groups between sampling times. However, only one vereda exhibited a reduction in functional richness, and neither showed temporal functional divergence. Woody encroachments are leading these veredas to an alternative state with a reduced herbaceous diversity, structurally denser, and with more resource-acquisitive plant traits in the community. The Woody encroachment reducing soil water availability, may impact ecosystem services, particularly water provision and biodiversity loss in the Cerrado region.