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The latest phylogenetic and taxonomic studies emphasizing Phyllanthus (Phyllanthaceae) have significantly altered the relationships between its taxa. In this work, we inferred a phylogeny for the Brazilian phyllocladiferous species of Phyllanthus, traditionally included within Phyllanthus sects. Choretropsis and Xylophylla from eastern Brazil and Caribbean, respectively. Our analysis demonstrated that Brazilian phyllocladiferous species has no relation to P. sect. Xylophylla from the Caribbean, but sect. Choretropsis, as it currently stands, does not form a monophyletic group. Thus, phylloclades arose in Phyllanthus at least in five distinct clades. Most species of sect. Choretropsis are recovered among representatives of other groups (sects. Antipodanthus and Phyllanthus subsect. Claussenianii), but no macromorphological feature could be traced for the clades we recovered. One exception is a clade containing P. dracenoides, P. gladiatus and P. pedicellatus, species with dracenoid habit and exclusive to the humid dense forests along Atlantic Forest domain, for which we describe a new section. [ABSTRACT FROM AUTHOR]

Homegarden (HG) agroforestry combines biological carbon (C) sequestration with biodiversity conservation outcomes. Although C stocks and species richness of HGs vary along elevational gradients and as a function of holding sizes, there is no consensus on the nature and magnitude of such variations. Field studies were conducted in the Western Ghats region of central Kerala, India (180 homesteads in 20 selected panchayats), to evaluate the effects of elevation (near sea level to 1938 m) and garden size (162–10,117 m2) on aboveground C stocks and floristic diversity. The C stocks (per unit area) of HGs (arborescent species) were highly variable (0.63–93.65 Mg ha–1), as garden management was highly individualistic and it exhibited a weak negative relationship with elevation. Likewise, there was a weak negative relationship between C stocks and garden size. Tree stocking levels (stems/garden) and species richness (species/garden) positively impacted total C stocks per garden. Floristic diversity was high in the study area (753 species) and included many rare and endangered species (43 IUCN Red-Listed species) making homegardens circa situm reservoirs of biodiversity. Elevation and holding size exerted a weak negative linear relationship on Simpson's floristic diversity index, which ranged from 0.26 to 0.93 for the arboreal species. Homegardens, regardless of elevation or size, contribute to C sequestration and agrobiodiversity conservation and help achieve the UN Sustainable Development Goals (SDGs), particularly Climate Action (SDG-13) and conserving agrobiodiversity (SDG-15, Life on Land). [ABSTRACT FROM AUTHOR]

Super-generalism is a pollinator trait where species obtain floral resources from a very wide range of plant species. Theoretical and empirical studies suggest that on islands with low pollinator diversity, such pollinators should evolve to exploit a very wide range of floral morphologies. Super-generalism has implications not only for securing pollination network stability, but also for the invasibility of potential weeds that require specialist pollinators in their original ranges. Here we expand earlier studies on bees in Fiji to include a wider range of bee-plant interactions for bees that have been recently introduced into Fiji as well as the endemic Fijian halictine bee, Homalictus fijiensis. Our data show that the endemic Fijian bee has a much wider range of floral hosts than introduced bees, and this extends to pollen larceny of solanoid plant species that are usually buzz pollinated. Importantly, solanoid plants were not visited by introduced bee species, including the honeybee Apis mellifera, which is usually regarded as a super-generalist. Our findings are important because they add critical support to the hypothesis that super-generalism evolves in insular ecosystems with low pollinator diversity and that this may make such ecosystems vulnerable to invasion by exotic weeds. However, insular super-generalists may also have potential to stabilize plant-pollinator networks and may also be effective pollinators for exotic crop species, and this needs to be further explored in agricultural settings. [ABSTRACT FROM AUTHOR]

Increasing trade in plants and plant products across continents heightens the risk of exotic insect pests expanding geographically into new habitats. This threatens not only the production and economic value of widely traded crops but the survival of species grown or sought by low-income communities. The first European outbreak of Scirtothrips dorsalis was detected in the Palm House collections at Kew in 2007 and triggered a monitoring program. This monitoring along with a robust review of the literature brought together information on new and known hosts for S. dorsalis. Further to this, we used molecular characterization techniques to identify which proposed cryptic species of S. dorsalis was present in this outbreak. The study revealed that 39% of the species of plants among the collections supported the proposed S. dorsalis South Asia 1 cryptic species, with over 50% of those species supporting immature life stages of the thrips confirming that they are suitable breeding hosts. Of particular importance are the newly identified hosts that are crops, and two further hosts reported as endangered/critically endangered. This study demonstrates the role that botanic garden collections can play in generating host relationship data that can feed into the development of robust predictive risk assessments for invasive insects. This can provide plant health authorities with the scientific basis for prioritizing management plans to protect important, vulnerable crop and non-crop plant species. [ABSTRACT FROM AUTHOR]

Alien species are often first introduced to urban areas, so it is unsurprising that towns and cities are often hotspots for invasions. However, while large cities are usually the first sites of introduction, small towns are more numerous and have a greater chance of launching invasions into natural areas as they have proportionally larger interfaces with their surroundings. In this paper we develop a set of scenarios as hypotheses to explore the role of small towns in facilitating within-country dispersal of alien plants. In particular, we developed ten scenarios for how introductions to small towns, agricultural and natural areas can lead to landscape-scale invasions. We tested a part of these scenarios using a case study of a highly invaded region in South Africa (the Berg River catchment in the Western Cape). We specifically investigated the main plant invasion routes between 12 small towns and their surrounding agricultural and natural areas. This was accomplished by conducting urban-specific alien plant surveys in towns, then comparing these results to regional databases of naturalized and/or invasive plants. Many of the alien plants found in urban areas were listed as invasive or naturalized in the catchment (over 30% of the total alien species pool). Despite marked environmental gradients across the study area, we found no relationships between the alien plant species richness in towns and climatic variables or with levels of anthropogenic disturbances. All towns hosted large numbers of invasive plant species and nearly half of the alien species found in towns were naturalized or invasive in surrounding areas. The likelihood of alien plants being naturalized or invasive outside urban areas increased in proportion to their local abundance in towns and if they were tall and woody. Ornamental horticulture was the main reason for introduction of these alien species (69%). Small towns can and do harbour significant populations of plant taxa that are able to spread to surrounding natural areas to launch invasions. Comparing lists of species from urban alien plant surveys with those from naturalisation records for the region is a useful protocol for identifying species which may be moving along the introduction-naturalization-invasion continuum. [ABSTRACT FROM AUTHOR]

Mutualisms are interactions from which both partners benefit but may collapse if mutualists' costs and benefits are not aligned. Host sanctions are one mechanism whereby hosts selectively allocate resources to the more cooperative partners and thereby reduce the fitness of overexploiters; however, many mutualisms lack apparent means of host sanctions. In mutualisms between plants and pollinating seed parasites, such as those between leafflowers and leafflower moths, pollinators consume subsets of the seeds as larval food in return for their pollination service. Plants may select against overexploiters by selectively aborting flowers with a heavy egg load, but in many leafflower species, seeds are fully eaten in some fruits, suggesting that such a mechanism is not present in all species. Instead, the fruits of Breynia vitis- idaea have stalk-like structures (gynophore) through which early-instar moth larvae must bore to reach seeds. Examination of moth mortality in fruits with different gynophore lengths suggested that fruits with longer gynophore had higher moth mortality and, therefore, less seed damage. Most moth mortality occurred at the egg stage or as early larval instar before moths reached the seeds, consistent with the view that gynophore functions to prevent moth access to seeds. Gynophore length was unaffected by plant size, extent of moth oviposition, or geography; thus, it is most likely genetically controlled. Because gynophores do not elongate in related species whose pollinators oviposit directly into the ovary, the gynophore in B. vitis- idaea may have evolved as a defense to limit the cost of the mutualism. [ABSTRACT FROM AUTHOR]

The floral development of Phyllanthus chekiangensis has been studied by scanning electron microscopy. The perianth organs are initiated in two whorls, dimerous in male flowers and trimerous in female flowers, with a longer plastochron between whorls than between the organs within a whorl. Male flowers have two stamens. The prominent connective protrusions begin development simultaneously with the floral disk. The disk is two-lobed in male flowers but continuous in female flowers. In female flowers, the developing gynoecium remains open relatively long, so the developing ovules are visible from the outside for some time. The direction of the hemitropous ovules in the carpels is antitropous (epitropous). Two small obturators are formed per carpel, one above each ovule. The prominent nucellar beak extends far beyond the 'micropyle'. A micropyle in the classical sense formed by integuments closing over the nucellus apex is not present at any stage of development. Thus, it is not correct to say that the nucellar beak 'grows through the micropyle'. The exposed nucellar beak continues the curvature of the antitropous (epitropous) ovule and becomes contiguous with the obturator. The unusual length of the nucellar beak may be a potential synapomorphy of the enlarged Phyllanthus clade as inferred from molecular phylogenetics. [ABSTRACT FROM AUTHOR]

The complete sequence of the chloroplast genome of cassava ( Manihot esculenta, Euphorbiaceae) has been determined. The genome is 161,453 bp in length and includes a pair of inverted repeats (IR) of 26,954 bp. The genome includes 128 genes; 96 are single copy and 16 are duplicated in the IR. There are four rRNA genes and 30 distinct tRNAs, seven of which are duplicated in the IR. The infA gene is absent; expansion of IRb has duplicated 62 amino acids at the 3′ end of rps19 and a number of coding regions have large insertions or deletions, including insertions within the 23S rRNA gene. There are 17 intron-containing genes in cassava, 15 of which have a single intron while two ( clpP, ycf3) have two introns. The usually conserved atpF group II intron is absent and this is the first report of its loss from land plant chloroplast genomes. The phylogenetic distribution of the atpF intron loss was determined by a PCR survey of 251 taxa representing 34 families of Malpighiales and 16 taxa from closely related rosids. The atpF intron is not only missing in cassava but also from closely related Euphorbiaceae and other Malpighiales, suggesting that there have been at least seven independent losses. In cassava and all other sequenced Malphigiales, atpF gene sequences showed a strong association between C-to-T substitutions at nucleotide position 92 and the loss of the intron, suggesting that recombination between an edited mRNA and the atpF gene may be a possible mechanism for the intron loss. [ABSTRACT FROM AUTHOR]

The most widespread invasive alien plant species in South Africa’s Kruger National Park (KNP) were either introduced unintentionally along rivers and roads, or intentionally for use as ornamentals. We examine the spatial distribution of ornamental alien plants in KNP, look at the link between human population size, history, and species richness, and show how the distribution of particular species reflects the likely history of ornamental plantings. Results are used to assess whether past management actions have been appropriately directed. Two hundred and fifty-eight alien species have been recorded in the 36 tourist camps and staff villages. The number of staff housed in villages explains much of the diversity of cultivated alien plant species. Older camps also tend to have more ornamental alien plant species. However, the lack of a strong link between camp age and number of cultivated species suggests that ornamental plants have been widely spread around the KNP by humans. We also show that increased camp activity (either size or age) has led to more ornamental species, while, with the notable exception of Skukuza, camp activity has had a much smaller effect on the number of noncultivated species. Noncultivated species tend to be naturally dispersed, as opposed to directly spread by humans between camps. Past management prioritized certain species on the basis of their potential to invade KNP and on the prevailing national legislation. These species were removed manually and follow-up control was carried out. Once the priority species were deemed to be under control, less invasive species were targeted. All alien species were removed from vacated houses, regardless of the potential invasiveness of the species. [ABSTRACT FROM AUTHOR]