Botanical Journal of the Linnean Sociey

Teixeira, Bruno; Teixeira, Gisele; Darnet, Elaine; Schaller, Hubert; Rogez, Hervé; Darnet, Sylvain

doi: 10.1093/botlinnean/boae060pmid: N/A

Achieving improved plant breeding is one of the most significant challenges facing efforts to ensure human nutrition and energy security over the next 30 years. The principal focus of plant breeding is to increase the production of conventional crops, but the domestication and breeding of lesser-known plants may also represent a source of food and energy. The African oil palm is an example of a cultivated plant that has reached the first rank of oil sources over the last four decades. Among palms, açai palm trees are highlighted due to the violet berries being commercialized internationally as functional foods. Açai palms are candidates for domestication and breeding and have a large area of cultivation. We reviewed the literature and technical reports concerning the açai genetic pool to detail the açai palm tree species and their biology, diversity centre, genetic resources, and existing breeding programmes.

Duckett, Jeffrey G; Renzaglia, Karen S; Pressel, Silvia

doi: 10.1093/botlinnean/boae055pmid: N/A

The recent realization that bryophyte sporophytes are homoiohydric enabled the present analysis of morphological features specifically associated with poikilohydry. The only morphological feature absolutely diagnostic of poikilohydry is schizolytic intercellular spaces. In vascular plants these are gas-filled from the outset, but in bryophytes are liquid-filled initially. They remain in this condition in liverwort gametophytes but become gas-filled following stomatal opening in hornworts and mosses. These have fixed apertures and are completely unresponsive to environmental cues. Stomata in Devonian fossils may have had similarly fixed apertures. Unistratose lamellae, characteristic of moss and liverwort leaves and pteridophyte gametophytes, are optimal structures for reversible cell shrinkage and recovery accompanying de- and rehydration. In 1 M sucrose, gametophytic tissues and filmy fern leaves undergo shrinkage, whereas sporophyte cells plasmolyse. Under extreme desiccation, hydroids are the only bryophyte cells to undergo cavitation. Like bryophytes, desiccation-tolerant streptophyte algae undergo reversible cell shrinkages. Mucilage secretion is unimportant in bryophyte desiccation biology and developmental differences rule out homology between the mucilage clefts and stomata in hornworts and Blasiales. Elaborate placental walls in basal liverwort lineages and a stomatal toolkit in the capsule walls of Haplomitrium suggest that liverworts’ ancestors may have had more complex sporophytes than those in extant taxa.

Mathews, Katherine G; Wheeler, Brandon; Silveira, Luiz

doi: 10.1093/botlinnean/boae058pmid: N/A

The taxonomic limits across Diervilla, a genus endemic to Eastern North America, are puzzling, compounded by broad morphological variation within species which may overlap across species. Here we used an integrative taxonomic approach to determine the degree of genetic, morphological, and geographical overlap across Diervilla species. We combined phylogenetic and quantitative analysis of ddRAD sequences, multivariate morphometrics, and qualitative morphological comparisons, and gathered occurrence data from herbarium specimens and samples collected anew. Species delimitation methods consistently identified D. lonicera as distinct, but disagreed on the limits between D. rivularis and D. sessilifolia. However, all three species can be consistently separated genetically, as revealed by principal coordinates analysis of the ddRAD sequences, as well as morphologically, as revealed by linear discriminant analysis of morphometric data. The distinctiveness across the three species was further confirmed by separate permutational analyses of variance. Moreover, the three species are largely separated geographically: D. lonicera is predominantly northern in distribution and restricted to higher elevations at lower latitudes, while D. rivularis and D. sessilifolia are parapatric in the Southern Appalachians. Informed by our integrative analyses, we provide information on geographical distributions and a dichotomous key for Diervilla species.

Carmo, João A M; Reginato, Marcelo; Sobrado, Sandra V; Miguel, Laila M; Janssens, Steven B; Dessein, Steven; Salas, Roberto M; Simões, André O

doi: 10.1093/botlinnean/boae059pmid: N/A

The Spermacoce clade, found primarily in the Americas, poses taxonomic challenges, notably in the unclear boundaries of Borreria and Spermacoce. These genera intertwine with smaller, morphologically distinct ones, including Psyllocarpus, a Brazilian endemic redefined into two sections. Psyllocarpus sect. Psyllocarpus, being based on the original genus delineation, encompasses nine species in the Cerrado and campo rupestre of eastern Brazil, and P. sect. Amazonica includes three species in the Amazonian campinas, while Psyllocarpus intermedius remains unclassified. Our phylogenetic study, sampling extensively across the Spermacoce clade for nuclear ribosomal (ETS and ITS) and plastid (rps16 and trnL-trnF) DNA regions and using a variety of approaches to analyse our dataset, revealed that Psyllocarpus is not monophyletic. Notably, P. campinorum (representing P. sect. Amazonica) and P. intermedius are distinct lineages in the Spermacoce clade but fall outside Psyllocarpus. Conversely, P. sect. Psyllocarpus forms a well-supported clade, closely related to Staelia. Therefore, Psyllocarpus has to be circumscribed based on its original concept, excluding P. sect. Amazonica and P. intermedius. This defines the genus as a distinct, easily diagnosable taxon. We provide a synoptic list of names and nomenclatural types of Psyllocarpus to formalize our results, with an updated description of the genus.

Marques, Natália F; Cunha Neto, Israel L; Brito, Lilian A; Somner, Genise V

doi: 10.1093/botlinnean/boae057pmid: N/A

Serjania is the only genus of the Paullinieae tribe that exhibits all patterns of vascular variants and includes S. piscatoria which shows a complex vascular structure that has intrigued botanists for centuries. Here, we analysed the stem development of S. piscatoria in an evolutionary context. We studied four individuals using standardized anatomical techniques and employed DNA sequencing to determine the species’ phylogenetic position. Additionally, we explored the evolution of stem developmental diversity using stochastic character mapping of the categories and patterns of vascular variants. We find that disparate ontogenetic processes determine the stem development in S. piscatoria, which results in vascular variants derived from procambial variants, cambial variants, and ectopic cambia. This diversity underscores the developmental lability of vascular meristems, making the species' vascular system structurally diverse and polymorphic. The complex vascular system observed in S. piscatoria evolved within a lineage composed of species with compound stems. These findings provide evidence for the intricate and labile evolutionary history of stem vasculature in Serjania, and the value of studying vascular variants to unravel the patterns and processes shaping plant diversity.

Sede, Silvana M; Testoni, Daniel; Sclovich, Sergio E; Morello, Santiago; Santín, Franco; Romaschenko, Konstantin; Starr, Julian R; Giussani, Liliana M

doi: 10.1093/botlinnean/boae056pmid: N/A

Generic delimitation within the tribe Stipeae has been a dynamic process since the late 1980s. In this study, we focus on a morphologically cohesive group of Jarava species with plumose-like awns that previous phylogenetic studies suggested were sister to the genus Pappostipa and only distantly related to Jarava sensu stricto. To test this hypothesis, we broadened species sampling, analysed lemma epidermal patterns, and performed molecular phylogenetic analyses using the nuclear ITS region and three plastid (rpl32-trnL, rps16-trnK, rps16 intron) markers. Phylogenetic results confirmed the close relationship of Jarava species with plumose awns (i.e., the Ptilostipa clade) to species of Pappostipa, forming a well-supported clade (C subclade). This result is supported by lemma epidermal patterns in the Ptilostipa clade that are similar to the ‘Maize-like’ pattern of the Achnatherum subtype found in Pappostipa. Consequently, we expand Pappostipa to include three species of Jarava (i.e., Pappostipa neaei, comb. nov., P. pogonathera, comb. nov., and P. psylantha, comb. nov.) and we place them in a new section, Pappostipa sect. Ptilostipa, sect. nov. Moreover, we provide new diagnostic features for Pappostipa, including drawings and photographs illustrating floret morphology, lemma epidermal surfaces, species’ habit, and notes on distribution.

Matel, Theodore P; Gandolfo, Maria A; Mitchell, John D

doi: 10.1093/botlinnean/boae071pmid: N/A

The Anacardiaceae are a characteristic angiosperm family of the Neotropics where they comprise ~32 genera and 200 species (~80 genera and 800 species globally). Among Neotropical Anacardiaceae genera, Schinus has the greatest species richness with 42 species distributed from tropical latitudes of Brazil and Peru south to the temperate steppe, matorral, and Valdivian temperate forest communities of Patagonia. Previous studies have found some anatomical and morphological leaf traits (e.g. simple vs. compound leaf organization) useful in characterizing lineages within Schinus, but also document traits that are homoplastic within the genus (e.g. stomatal distribution) and convergent among Schinus and its close relatives Lithrea and Mauria (e.g. mesophyll arrangement). Here, we present a survey of leaf cuticular traits in 53 species of Schinus and its closest relatives Lithrea, Mauria, and Euroschinus based on characters observed with scanning electron and optical light microscopy. We use ordinated Bray–Curtis distances based on 18 characters and 2D nonmetric multidimensional scaling to show that cuticular morphology resolves the three most diverse genera, Euroschinus, Mauria, and Schinus, but does not resolve intrageneric sections of Schinus. We propose that a distinctive acuminate gland type occurring only within Euroschinus may constitute a potential synapomorphy for this genus. Within Schinus, we find inconsistency in stomatal distribution among specimens of a single species, among species of a single section, and between sections of the genus, and suggest that current evidence is insufficient to implicate either phenotypic plasticity or homoplasy as the causative mechanism of this variation.

doi: 10.1093/botlinnean/boae073pmid: N/A