A comparison of leaf crystal macropatterns in the two sister genera Piper and Peperomia (Piperaceae)

Premise of the study: This is the first large-scale study comparing leaf crystal macropatterns of the species-rich sister genera Piper and Peperomia. It focuses on identifying types of calcium oxalate crystals and their macropatterns in leaves of both genera. The Piper results are placed in a phylogenetic context to show evolutionary patterns. This information will expand knowledge about crystals and provide specific examples to help study their form and function. One example is the first-time observation of Piper crystal sand tumbling in chlorenchyma vacuoles. Methods: Herbarium and fresh leaves were cleared of cytoplasmic content and examined with polarizing microscopy to identify types of crystals and their macropatterns. Selected hydrated herbarium and fresh leaf punches were processed for scanning electron microscopy and x-ray elemental analysis. Vibratome sections of living Piper and Peperomia leaves were observed for anatomical features and crystal movement. Key results: Both genera have different leaf anatomies. Piper displays four crystal types in chlorenchyma-crystal sand, raphides, styloids, and druses, whereas Peperomia displays three types-druses, raphides, and prisms. Because of different leaf anatomies and crystal types between the genera, macropatterns are completely different. Crystal macropattern evolution in both is characterized by increasing complexity, and both may use their crystals for light gathering and reflection for efficient photosynthesis under low-intensity light environments. Conclusions: Both genera have different leaf anatomies, types of crystals and crystal macropatterns. Based on Piper crystals associated with photosynthetic tissues and low-intensity light, further study of their function and association with surrounding chloroplasts is warranted, especially active crystal movement

Book review "Flora Mesoamericana Volumen 2, Parte 2, Piperaceae"

Reseña del libro "Flora Mesoamericana Volumen 2, Parte 2, Piperaceae"  Book review "Flora Mesoamericana Volumen 2, Parte 2, Piperaceae"

Acta Botanica Mexicana, hacia una revista electrónica de alta calidad

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First record of the critically endangered Hydrangea steyermarkii Standl. (Hydrangeaceae) in Mexico, and description of a new widespread Hydrangea species of Mesoamerica

Based on our detailed observations in the field, completed with herbarium material of representatives of Hydrangea section Cornidia in southeastern Mexico and Central America, we found that Hydrangea steyermarkii Standley, in contrast to what has been assumed up to now, is restricted to the Tacana Volcano on the border of Mexico and Guatemala. The majority of the specimens with reddish or whitish indument on their branches in South East Mexico and Central America, belonging to this nearly exclusively Neotropical Hydrangea clade, had been identified as such, but the characters of these collections do not coincide with the single type specimen of H. steyermarkii, neither with other individuals of this species growing in the type locality area. In fact, nearly all specimens of Mesoamerica that had been identified as this species belong to a new species with a relatively wide distribution, which we describe here. This new species is illustrated and compared with H. steyermarkii, of which we also provide an amended description and illustrations. Finally, on the basis of these two species we document previously suggested dioecism in this plant group, which not only has consequences for systematics and nomenclature in this clade, but also for conservation

Verhuellia is a segregate lineage in Piperaceae: more evidence from flower, fruit and pollen morphology, anatomy and development

Background and Aims The perianthless Piperales, i.e. Saururaceae and Piperaceae, have simple reduced flowers strikingly different from the other families of the order (e.g. Aristolochiaceae). Recent molecular phylogenies proved Verhuellia to be the first branch in Piperaceae, making it a promising object to study the detailed structure and development of the flowers. Based on recently collected material, the first detailed study since 1872 was conducted with respect to morphology, anatomy and development of the inflorescence, pollen ultrastructure and fruit anatomy. Methods Original Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Light Microscopy (LM) observations on Verhuellia lunaria were compared with Piperaceae, Saururaceae and fossils. Key results The inflorescence is an indeterminate spike with sessile flowers, each in the axil of a bract, developing in acropetal, helical succession. Flowers consist of two (occasionally three) stamens with basifixed tetrasporangiate anthers and latrorse dehiscence by a longitudinal slit. The gynoecium lacks a style but has three to four stigma branches and a single, basal orthotropous, and unitegmic ovule. The fruit is a drupe with large multicellular epidermal protuberances. The pollen is very small, inaperturate, and areolate with hemispherical microechinate exine elements. Conclusions Despite the superficial similarities with different genera of Piperaceae and Saururaceae, the segregate position of Verhuellia revealed by molecular phylogenetics is supported by morphological, developmental and anatomical data presented here. Unitegmic ovules and inaperturate pollen, which are synapomorphies for the genus Peperomia, are also present in Verhuellia

Discordant phylogenomic placement of Hydnoraceae and Lactoridaceae within Piperales using data from all three genomes

Original ResearchPhylogenetic relationships within the magnoliid order Piperales have been studied extensively, yet the relationships of the monotypic family Lactoridaceae and the holoparasitic Hydnoraceae to the remainder of the order remain a matter of debate. Since the first confident molecular phylogenetic placement of Hydnoraceae among Piperales, different studies have recovered various contradictory topologies. Most phylogenetic hypotheses were inferred using only a few loci and have had incomplete taxon sampling at the genus level. Based on these results and an online survey of taxonomic opinion, the Angiosperm Phylogeny Group lumped both Hydnoraceae and Lactoridaceae in Aristolochiaceae; however, the latter family continues to have unclear relationships to the aforementioned taxa. Here we present extensive phylogenomic tree reconstructions based on up to 137 loci from all three subcellular genomes for all genera of Piperales. We infer relationships based on a variety of phylogenetic methods, explore instances of phylogenomic discordance between the subcellular genomes, and test alternative topologies. Consistent with these phylogenomic results and a consideration of the principles of phylogenetic classification, we propose to exclude Hydnoraceae and Lactoridaceae from the broad circumscription of Aristolochiaceae, and instead favor recognition of four monophyletic and morphologically well circumscribed families in the perianth-bearing Piperales: Aristolochiaceae, Asaraceae, Hydnoraceae, and Lactoridaceae, with a total of six families in the orderinfo:eu-repo/semantics/publishedVersio

Disentangling species delineation and guiding conservation of endangered magnolias in Veracruz, Mexico

The Mexican state of Veracruz has suffered very high deforestation rates in the last few decades, and despite the establishment of protected areas and conservation projects, primary forest is now mainly persisting in mostly small, scattered, fragmented remnants. New species of Magnolia section Talauma in this state have been described with little to no reference to the already existing ones, potentially resulting in over-splitting, obscuring their taxonomic delineation and conservation status, and consequently conservation programs. To study the conservation units and their genetic diversity, we here employ 15 microsatellite markers on a highly representative sampling of 254 individuals of what are presumed to be five Magnolia species. The results support at least three species and maximum five main conservation units. We propose downgrading the latter to four, given morphological, ecological, demographical, and geographical considerations. Two out of the three sympatrically occurring species in the rainforest in the Los Tuxtlas volcanic area have weak genetic evidence to be considered separate species. Similarly, the individuals in the Sierra de Zongolica in central Veracruz, who bear a very high morphological and genetic similarity to Magnolia mexicana, have weak genetic evidence to be recognised as a separate species. Nonetheless, the individuals could be identified as Magnolia decastroi based on morphology, and further research including the full range of this species is recommended

Molecular phylogenetics and new (infra)generic classification to alleviate polyphyly in tribe Hydrangeeae (Cornales : Hydrangeaceae)

Tribe Hydrangeeae of Hydrangeaceae currently contains nine morphologically diverse genera, many of which are well-known garden ornamentals. Previous studies have shown eight of these genera to be phylogenetically nested within Hydrangea, rendering the latter polyphyletic. To clarify the phylogeny of tribe Hydrangeeae, the present study sequenced four chloroplast regions and ITS for an extensive set of taxa, including the type for all nine genera involved. The resulting phylogenetic hypotheses corroborate the polyphyly of Hydrangea. Since polyphyletic taxa are deemed unacceptable by both sides in the ongoing debate concerning the adherence to strict monophyly in biological classifications, a new (infra)generic classification for tribe Hydrangeeae is proposed. In order to create a stable, evolutionary informative classification a broader circumscription of the genus Hydrangea is proposed, to include all eight satellite genera of the tribe. Such treatment is considered highly preferable to an alternative where Hydrangea is to be split into several morphologically potentially unidentifiable genera. To facilitate the acceptance of the new classification proposed here, and in order to create a classification with high information content, the familiar generic names were maintained as section names where possible