Andrea Susana Vega

Constituting the first synopsis on woody bamboos in southern South America, this contribution provides a comprehensive overview of its 12 native genera. The synopsis includes botanical descriptions for each genus, a complete checklist of the taxa, as well as information on their habitat, uses and applications, and flowering period. Furthermore, it provides keys that allow for the identification of the genera: one based on vegetative characters, and the other on both vegetative and reproductive characters.

Digitaria sanguinalis (L.) Scop. (large crabgrass) is a globally distributed annual C ₄ grass and one of the most challenging weeds in agriculture, causing significant yield losses in crops such as maize, soyabean, rice, cotton and vegetables. This species thrives under favourable and unfavourable conditions such as disturbed soils, fluctuating temperatures and shallow burial, making it resilient within various cropping systems. Integrated weed management strategies combining biological, chemical, cultural and mechanical methods have shown variable success in managing Digitaria sanguinalis . However, this species shows herbicide resistance through both target‐site mutations and metabolic mechanisms, complicating its control. Despite its allelopathic effects, it offers value as livestock forage and holds potential for bioenergy through pyrolysis and combustion. This review examines the biology, ecology, distribution and current management techniques of D. sanguinalis , offering insights to help growers and researchers develop successful crop management strategies.

Bamboo cultivation in Argentina could represent a major economic activity if its various applications were revealed. This study characterized the anatomy and micromorphology of leaf blades by optical and scanning electron microscopes. Foliage leaves presented predominant parenchyma and scarce sclerenchyma. Foliage chemical and biological composition were analyzed in 3 populations of P. aurea sampled in two contrasting seasons of the year. The six samples evaluated showed 13% protein, adequate for ruminant feed. Neutral detergent fiber (aNDFom) was approximately 60% DM, a probable limiting factor for consumption. Significant differences in ADFom (acid detergent fiber) and ADLom (acid detergent lignin) favored spring results, with lower values than winter results. The presence of silica in different cell types could limit digestion. Fermentation kinetics indicated that dry matter digestibility is close to 50%, and higher in spring given lower amounts of indigestible components. In addition, all samples analyzed had a low content of immediately soluble material and a high content of potentially fermentable insoluble material. Anatomy and chemical-nutritional characterization allow P. aurea foliage to be considered in ruminant feeding. Highlights: Nutritional and morpho-anatomical studies are complementary in the evaluation of forages for ruminants. Anatomy and chemical-nutritional characterization allow aurea foliage to be considered in ruminant feeding. Silica in epidermis, trichomes, cell walls or lumen of grasses acts as structural inhibitor of microbial digestion leading to lower acceptability and DMD. The high silica content accounts for 82% of the total ash, suggesting the presence of indigestible substances. Phyllostachys aurea foliage leaves showed 13% protein, adequate for ruminant feed and neutral detergent fiber was approximately 60%DM.

El presente trabajo reporta siete nuevos registros de Agrostis en América Central y del Sur: A. boyacensis en Bolivia, Peru y Venezuela, A. lenis en Colombia, Ecuador y Venezuela, y A. mertensii en Costa Rica. Se designa el lectotipo de Agrostis williamsii. El trabajo incluye la sinonimia, iconografía, distribución geográfica y hábitat, fenología, estado de conservación de acuerdo con las categorías de amenaza de la IUCN, usos y la lista de especímenes adicionales examinados.

Rúgolo de Agrasar recognized two varieties of Deyeuxia velutina (D. velutina var. velutina and D. velutina var. nardifolia) based on leaf sheath indumentum, lemma length, and leaf blade direction. However, taxonomic delimitation has been difficult due to occasional overlapping characters. To assess the infraspecific delimitation of D. velutina, we present a comprehensive study combining morphometric analyses and a potential distribution model. To explore morphological variation and select diagnostic characters, we measured 124 morphological characters in 52 specimens of both varieties and performed a principal coordinate analysis and univariate analyses (Analysis of variance and Kruskal-Wallis non-parametric test). Both taxa resolved as separate morphological groups. Additionally, a Discriminant Analysis was performed to classify the individuals in the predetermined morphological groups. For modeling the species distribution, 26 specimens of D. velutina var. nardifolia and 68 of D. velutina var. velutina were georeferenced and 20 environmental variables were analyzed through a Maximum Entropy model. Deyeuxia velutina extends in the high Andean region from Peru to southern Argentina and Chile. Both varieties differed in their geographical limits, a result supported by regression analyses of latitude and longitude on the principal coordinates of the PCoA. Deyeuxia velutina var. nardifolia is restricted to the northern area of distribution while D. velutina var. velutina showed a higher habitat suitability in the southern region. Moreover, D. velutina var. nardifolia is here reported for the first time in San Juan province (Argentina), constituting the austral limit of its geographical distribution. Additional reliable morphological characters were considered in an updated key to the varieties.

Agrostis laegaardii A. M. Molina & Rúgolo (Poaceae), a new species restricted to the high páramos from Colombia and Ecuador, is described and illustrated. It is morphologically most similar to A. breviculmis Hitchc. but differs in spikelet length, pedicel apex, glume texture, relative distance between upper glume and floret, lemma and palea length, and the presence of an awn on the lemma. Micromorphology of the spikelet is discussed, and a Trichodium net is reported on the epidermis of the lemma. A distribution map and a key to the Colombian and Ecuadorean species of Agrostis L. with contracted inflorescences are provided.