Nitrogen-fixing symbiosis in root nodules is known in only 10 families, which are distributed among a clade of four orders and delimited as the nitrogen-fixing clade. As the seventh in a series that examines pollen morphological distribution and evolution in the angiosperms, this paper focuses on pollen morphological character states of the nitrogen-fixing clade. To illustrate the palynological diversity of the clade, we first examined pollen grains from 26 species with light electron, scanning electron, and transmission electron microscopy. Second, we used a reduced data matrix from Li et al. (2015) to reconstruct a maximum likelihood tree and then optimized 18 pollen character states onto the tree using Fitch parsimony, maximum likelihood, and hierarchical Bayesian inference. Finally, 12 plesiomorphic states for the nitrogen-fixing clade were inferred unambiguously under all methods, and more than 40 clades (or lineages) at or above familial level were characterized by unambiguous pollen character state changes in at least one of the optimizations. We found a number of evolutionary trends for changes in pollen character states. These include increasing grain size, increasing aperture number accompanied by concomitant changes in aperture position (from equatorial to global) and aperture shape (from colpate to colporate), and increasing complexity of tectum ornamentation. There was a strong correlation between some pollen characters (prolate shape class, lobe outline in polar view, colpate ectoaperture, lalongate and lolongate endoaperture, absent supratectal element, reticulate tectum) and insect pollination, while other pollen characters—simple aperture structure, porate ectoaperture, circular endoaperture, present and gemmate or echinate supratectal element, and imperforate tectum—were strongly correlated with wind pollination. In addition, rugulate tectum was significantly correlated with shrub habit while larger pollen size was significantly correlated with vine habit; the helophytic habitat was significantly correlated with having two apertures. Our study provides rich evidence for the phylogenetic significance of pollen morphological diversity in the nitrogen-fixing clade.

Chusquea Kunth (Poaceae, Bambusoideae, Bambuseae) es considerado el género de bambúes leñosos más rico en especies a nivel mundial. En el extremo sur de Sudamérica, se encuentran numerosas especies de Chusquea que constituyen el componente dominante del sotobosque y son endémicas de la región. La posición taxonómica de algunas de estas especies ha suscitado mucha controversia. En este trabajo, se presenta la revisión taxonómica de las especies nativas del género Chusquea en Chile, que incluye la sinonimia, descripciones, iconografía, distribución geográfica, hábitat, fenología, nombres vulgares y una clave para la identificación de las 13 entidades reconocidas (12 especies y una forma) sobre la base de caracteres morfológicos vegetativos y reproductivos. Chusquea andina Phil. y C. gigantea Demoly se incluyen por primera vez en un tratamiento taxonómico, estableciendo sus diferencias con entidades afines y, de esta forma, dilucidando el complejo de especies C. culeou E. Desv. Asimismo, C. fernandeziana Phil. se ilustra en forma completa por primera vez.

Ephedranthus S. Moore is a Neotropical genus of Annonaceae distributed from Colombia and the Guianas to Bolivia and southeastern Brazil, comprised of seven species: E. amazonicus R. E. Fr., E. boliviensis Chatrou & Pirie, E. colombianus Maas & Setten, E. dimerus J. C. Lopes, Chatrou & Mello-Silva, E. guianensis R. E. Fr., E. parviflorus S. Moore, and E. pisocarpus R. E. Fr. The genus is recognized by the combination of leaves with impressed adaxial veins, short pedicels, two to five bracts, androdioecy (i.e., some plants with only staminate flowers, other plants with only bisexual flowers), and 1-seeded monocarps. This revision updates the knowledge about the genus, providing a morphological phylogenetic analysis of Ephedranthus species, with a key, descriptions, distribution maps, and illustrations of the diagnostic characters of the species. The phylogenetic analysis shows Ephedranthus defined by having staminate flowers and basal placentation, and the seven species related as ((E. colombianus, E. boliviensis) ((E. guianensis, E. amazonicus) (E. dimerus (E. parviflorus, E. pisocarpus)))); based on this, the current subdivision of Ephedranthus is not monophyletic, and the sections are here synonymized.

The taxonomic treatment of the 18 species composing the Tillandsia utriculata L. complex s.l. is presented. A description and a diagnosis of the group are provided, as well as two artificial keys to species, each emphasizing characters from living plants or from exsiccatae, respectively. Complete taxonomic information is given, including taxonomic citation, synonymy, etymology or eponimy, description, specimens examined, phenology, nomenclatural notes, relationships and diagnostic characters, variation, ecology and distribution, together with plates of living plants and vegetative and reproductive structures, as well as maps of distribution.

Methods of macroevolutionary systematics as recently modified are explained and applied to the genus Anoectangium Schwägr. (Pottiaceae) in hyperoceanic areas of coastal northwestern North America. It was revealed that this area harbored species like those reported for the Himalayan region of northern India. Keys are provided for North American and Himalayan species of the genus. A macroevolutionary analysis, detailed in the Methods section, distinguishes and gives relationships between the species. There is strong Bayesian support for progenitor-descendant pairs and lineages. Anoectangium thomsonii Mitt. is considered a synonym of A. aestivum (Hedw.) Mitt. Anoectangium crassinervium Mitt. is transferred to Molendoa Lindb., under a nomen novum with A. handelii Schiffn. as a synonym. Anoectangium incrassatum Broth., related to the Asian A. clarum Mitt., is reported as a well-characterized species from the West Indies. Anoectangium stracheyanum Mitt. is re-lectotypified. Distinctions between A. aestivum and A. euchloron (Schwägr.) Spruce in the New World are clarified. Causal explanations in systematics are equated with entropy maximization in Shannon information analysis in the context of serial descent. A Pleistocene species pump hypothesis is advanced to explain the stenomorphic populations of species of the genus in eastern North America.