Abstract—Costus flammulusis a new herbaceous species endemic to montane cloud forests of the volcanic cordilleras in northern Costa Rica.Costus flammulushas been mistaken forC. wilsonii, but phylogenetic evidence demonstrates that it is closely related to the widespread lowland speciesC. pulverulentus. Here, we use an integrated framework of species concepts to evaluate whetherC. flammulusandC. pulverulentusare distinct species. First, we re-evaluate prior phylogenetic analyses to assess whetherC. flammulusbifurcated from or budded off from withinC. pulverulentusand whetherC. flammulusis monophyletic. We then compare phenotypic traits to determine which diagnostic vegetative and inflorescence traits can be used to identify species in herbarium specimens and examine whether floral traits may confer floral isolation. We compare pollinator assemblages to examine whether pollinator specificity may contribute to reproductive isolation. Finally, we model species distributions and climatic niche overlap to assess ecogeographic isolation. We found thatC. flammulusis a monophyletic species phenotypically, ecologically, and geographically distinct fromC. pulverulentusand may have speciated as a peripheral isolate at the high elevation range edge ofC. pulverulentus. Several lines of evidence, such asC. pulverulentusparaphyly, range size asymmetry, andC. flammulus’nested distribution and vegetative traits, suggest thatC. flammulusbudded off from aC. pulverulentus‐like progenitor species, evolving to tolerate a colder and more seasonal montane environment.

Abstract—The fern genusDidymochlaenais characterized by having scaly rhizomes and petioles, tufted and bipinnate leaves, dimidiate pinnules, and fewer than 11 sori per pinnule. For a long time only one species was widely recognized in the genus. Most recently, six and seven species from Madagascar and Asia-Pacific regions, respectively, have been recognized based on morphological and/or molecular evidence. In this monographic study we recognize 22 species worldwide, six of which are described as new:D. alpina,D. amazonica,D. cameroonensis,D. comorensis,D. cubensis, andD. mesoamericana. A key to all species is provided, and detailed descriptions, illustrations, and information on their distribution and habitats are given.

Abstract—We here describe a new species of flowering plant to science,Ruellia whitneyana(Acanthaceae), so far known only from Bolivia. This species occupies wet forest understories associated with steep slopes and riparian environments, where plants grow directly atop slate rocks or among rocky soils. We postulate that this new species is of hybrid origin betweenRuellia brevifoliaandRuellia puribased on recurrent sympatry and simultaneous co-flowering, intermediate vegetative and floral morphological features, and evidence from genomic and palynological data.

Abstract— Tomato domestication history has been revealed to be a highly complex story. A major contributor to this complexity is an evolutionary intermediate group (Solanum lycopersicum var. cerasiforme; SLC) between the cultivated tomato (Solanum lycopersicum var. lycopersicum; SLL) and its wild relative (Solanum pimpinellifolium; SP). SLC includes accessions with a broad spectrum of genomic and phenotypic characteristics. Some of the SLC accessions were previously hypothesized to be spreading northward from South America into Mesoamerica and that migration probably entailed reversal to wild-like phenotypes such as smaller fruits. Prior to this study, the northernmost confirmed extension of the SLC was limited to northern Mexico. In this study, we employed genomic methods to investigate the origin of a wild-like tomato found in a garden in Scottsdale, Arizona, USA. The so-called “Arizona tomato” featured a vigorous growth habit and carried small fruits weighing 2‐3 g. Our phylogenomic analyses revealed the identity of the Arizona tomato as a member of the Mexican SLC population (SLC MEX). To our knowledge, this is the first report of an SLC accession, confirmed using genomics, growing spontaneously in Arizona. This finding could have implications for conservation biology as well as agriculture.

Abstract— Monardella (Lamiaceae) is a taxonomically complex western North American genus ranging from the Pacific coast to the western slopes of the Rocky Mountains and from southern British Columbia in Canada to the Cape region of Baja California Sur in Mexico. We applied a combination of gross vegetative morphology, trichome morphology and abundance/distribution, and molecular data to clarify taxonomic discontinuities, specifically regarding the monophyly of plants formerly treated within Monardella odoratissima. The data suggest a clear distinction between the non-monophyletic M. odoratissima species complex and the M. ovata species complex, thus resolving taxonomic ambiguities within and between them. We formally recognize plants from southern Oregon, northern California, and western Nevada previously misapplied to M. odoratissima as belonging to the M. ovata species complex. We introduce the following taxonomic and nomenclatural revisions: describe M. ovata Greene subsp. lenmaniae as a novel subspecies; present M. ovata subsp. pallida at a new position and rank; recognize M. modocensis, M. ovata, and M. rubella as accepted taxa; designate lectotypes for M. modocensis and M. rubella; and designate M. californica and M. tortifolia as new synonyms under M. ovata.

Abstract— Two new species, Phyllanthus lilliputianus and Phyllanthus sobralii are described for the Atlantic Forest of Southeastern Brazil, for the states of Espírito Santo and Minas Gerais, respectively. The presence of deeply emarginate anthers and four-colporate pollen grains with reticulate and microreticulate exine indicate that both species belong to Phyllanthus sect. Phyllanthus subsect. Claussenianii. Phyllanthus lilliputianus is an erect and small herb, with mucilaginous-hyaline branchlets, stipules, and petiole, an elliptical leaf blade that is membranaceous and sparsely mucilaginous-hyaline, staminate flowers with 5 sepals rhombic to widely obovate, and pistillate flowers with 5 slightly unguiculate sepals. P. sobralii is characterized by an herbaceous habit, with cylindrical branchlets that are glabrous, fractiflex and pinnatiform, leaf blades broadly elliptical to oval-elliptical, turquoise with prominent ribs on both surfaces, staminate and pistillate flowers with 5 sepals, with an accentuated central strip. Detailed description, colored plates, line drawing, notes on distribution, and conservation assessment are provided below.

Abstract— Recent molecular phylogenetic studies have identified four major clades within the fern genus Tectaria but none of them is supported by any morphological characters. Here we present an expanded phylogeny of Tectaria based on five plastid markers (atpB, ndhF + ndhF-trnN, rbcL, rps16-matK + matK, and trnL-F), with a particular focus on the species from Asia to the Solomon Islands. Our aims are to infer the systematic position of newly included species, providing insights to interspecific relationships of some species groups, and to determine the identity of some specimens with distinct morphology. As a result, three major clades and a total of 14 lineages are identified in Asia to the Solomon Islands. The 19 newly sampled species were well resolved in the phylogenetic tree, of which T. lobbii (representative of rare rheophytes in Tectaria) was confirmed as belonging in the T. angulata‐T. vanikoroensis lineage. Four new species from the Solomon Islands, T. acrophoroides, T. glenniana, T. pallescens, and T. vanikoroensis, are recognized and described. Phylogenetic and morphological evidence suggests frequent hybridizations between T. crenata and T. decurrens from Malesia to the Solomon Islands, and between T. devexa and T. simonsii in mainland Asia and adjacent islands, which render the obscure species boundaries within the two groups.

Abstract—We herein present nomenclatural and taxonomic novelties inCaleasect.Meyeriafrom Brazil.Calea pruskianais a new species related toC. trianthaand can be distinguished by the acute or cuneate, rarely attenuate leaf apex (vs. obtuse), slightly branched capitulescence (vs. profusely branched), and ray florets 18‐21.7 mm long (vs. 9.2‐15.3 mm).Calea hispidaf.subintegerrimais lectotypified, recombined, and elevated to species level asCalea subintegerrima, which also resemblesC. triantha, however differs from it by the usually glabrous abaxial leaf surface (vs. usually hispid), glandular-punctate peduncle (vs. glands absent), and cypselae with hirsute ribs (vs. pilose ribs). These species are described and illustrated, their geographic distributions are mapped, and their taxonomic affinities are discussed. Furthermore, a new terminology is proposed to describe more accurately the pappus scale size variation according to the relative length of the scales and the occurrence of combinations of pappus scales of different lengths in the same capitulum.

Abstract— Justicieae is one of the largest tribes of Acanthaceae, composed of 2000 species distributed in 100 genera, with highest diversity in the neotropical region. Palynological studies containing several representatives of the tribe are rare, specially species from Northeastern Brazil. The present study aims to differentiate species and evaluate palynological characters in the light of a phylogenetic hypothesis of Justicieae. Eighteen species belonging to six genera were analyzed. Pollen grains were acetolyzed, measured and photographed under light microscopy (LM) and scanning electron microscopy (SEM). Pollen grains are medium to very large in size, isopolar, planaperturate, subprolate, prolate to prolate spheroidal, and two-colporate to three-colporate, or with six pseudocolpi. The exine ornamentation is microreticulate to reticulate with areolae between the apertures in most species. Some species present a cavea in the mesocolpium. The pollen morphology of Justicia chamaedryoides, J. congrua, J. glaziovii, J. thunbergioides, J. sphaerosperma, Pseuderanthemum congestum, and P. modestum are hereby described for the first time. A new combination is also proposed, Thyrsacanthus angustissimus.