El cariotipo de Paspalum cromyorrhizon diploide y tetraploide (Poaceae, Panicoideae, Paspaleae)

Paspalum cromyorrhizon Trin. ex Döll is a species adapted to low and humid fields, river and stream banks, throughout S Brazil, Uruguay and NE Argentine. Diploids (2n = 2x = 20) and tetraploids (2n = 4x = 40) from natural populations of P. cromyorrhizon from Corrientes (Argentina) were used to analyse the karyotype morphometry of both cytotypes. The chromosome count was performed using classical Feulgen staining. The karyotype of diploid P. cromyorrhizon has 20 metacentric chromosomes, while the tetraploid has a karyotype of 40 metacentric chromosomes. The total length of the chromosomal complement in diploids is 32.5 μm and in tetraploids 63.5 μm, the total monoploid chromosome length is 15.48 μm in diploids and 15.21 μm in tetraploids and both karyotypes are symmetrical. Karyotype analysis confirms the autopolyploid origin proposed for tetraploids.

First record of the family Mazaceae (Lamiales) in Colombia and the clarification of the synonyms of Mazus pumilus

Mazaceae, a family native to Asia and Oceania, is reported for the first time for the Colombian flora, with Mazus pumilus (Burm.f.) Steenis. This species is easily recognized by its herbaceous habit, leaves rosulate, elliptic to obovate cauline leaves, terminal, racemose inflorescences, bilabiate flowers with one 2-lobed upper lip and one 3-lobed lower lip, and fruit completely enclosed in the calyx. To date, this species has been recorded in three departments of Colombia, growing between the pavement. Additionally, we clarify the synonyms of this taxon.

Las especies de Splachnaceae (Bryophyta) de Tierra del Fuego, Argentina: las esporas y sus modos de dispersión

The Splachnaceae family is a bryological component of the temperate forests of Nothofagus in the Fuegian region of Argentina. It is represented by the Tayloria genera with three species, T. dubyi (endemic), T. magellanica, T. mirabilis, and Tetraplodon, with a single specie Tetraplodon fuegianus. They grow on organic substrates of animal origin and are the only family among mosses in the area in which entomochory is observed (i.e. dispersion of spores through insects). From herbarium material, the taxonomic features of gametophytes and sporophytes which allow species to be identified are described. Spores were studied with OM and SEM. Dispersal vectors for Tayloria mirabilis and morfo-ecological adaptations associated with entomochory were observed and analyzed. Mosses are differentiated from their leaves and the morphology and color of the sporophyte capsules. The spores, similar in the studied species, are dispersed in sticky masses, they are spheroidal, monoletes, 8-13 μm of diameter with a pitted-reticulate ornamentation. The dispersing agents mostly correspond to the order Diptera. The Splachnaceae family has developed adaptive strategies in relation to substrate (coprophilous gametophytes), in striking and showy sporophytes morphologies and in a particular dispersal mode of the spores by insects. All these morpho-ecological adaptations contribute to an effective action of the dispersing agents in the muscinal biocenosis.

A new species of Utricularia Sect. Orchidioides (Lentibulariaceae) from the Amotape-Huancabamba Zone of North Peru

A new species of Utricularia Section Orchidioides: Utricularia amotape-huancabambensis sp. nov. (Lentibulariaceae), endemic to Northern Peru is described and illustrated. It is known from two populations so far, both located in the Province Bongará, Dpto. Amazonas at ca. 2200 m altitude. The new species inhabits the páramo of the low white sandstone plateaus, an extension of the southern branches of the Condor mountain range in the southeastern part of the Amotape-Huancabamba phytogeographic zone. A diagnosis, description, etymology and an identification key covering the Andean and selected similar species of the section are presented. The distribution, habitat, ecology, associated flora, preliminary conservation status, an observed hybridization with sympatric U. unifolia and the affinities of the new species with other related taxa are discussed. The new species is known from two close-by populations in the same region and likely affected by anthropic pressure. Threatening changes in land use, resulting in habitat fragmentation or loss or changing water regimes in the course of climate change will have severe consequences for the sensitive páramo ecosystem and thus the populations of U. amotape-huancabambensis. Therefore, this new spectacular species of Utricularia is preliminarily considered Critically Endangered (CR).

Morfoanatomía del tallo con crecimiento secundario de especies de Jatropha (Euphorbiaceae) nativas de la Región Chaqueña Argentina y su relación con el ambiente

Jatropha (Euphorbiaceae) is a morphologically diverse genus with pantropical distribution. It includes 180 species growing worldwide and has a broad range of uses: medicinal, ornamental and biodiesel production. In Argentina there are ten native species, distributed from the north to the center of the country, and one adventitious. However, the morphoanatomy of the native species of Jatropha is scarcely known, and so far, no anatomical studies of the stem with secondary growth have been performed in any of the native species. In this work, we analyzed the anatomy of the stem with secondary growth of three native species: J. excisa, J. hieronymi and J. macrocarpa, considering aspects related to the arid environment in which plants live, to provide information that it is useful for their conservation and possible sustainable use. Woody branches of each species were collected and fixed to perform temporary histological preparations of transverse and longitudinal sections of stems. We described their morphoanatomy under a light microscope. The following variables were analyzed: xylem area/total area of the stem, number of vessels per mm2, vessel diameter and length of conductive elements. Indices were obtained to assess the drought vulnerability, the plant mesomorphy degree and to determine vessel clustering. The stems analyzed have several anatomical characters that are typical of plants that inhabit xerophytic environments, and that favor their development despite the scarce rainfall and high temperatures, including: suber and phelodermis with thickened cell walls; inner cortex with various cell layers; presence of chollenchyma; presence of chlorenchyma; ergastic substances in the cortex, vascular tissues and medullary parenchyma (latex, crystals and starch granules); short, narrow, numerous and grouped xylem vessels. The evaluated indexes suggest that the three taxa have a safe and efficient conduction system for water movement, being J. macrocarpa the most drougth resistant. This study provides novel information about these three species of biological, industrial, and economic importance, which are potential sources for biodiesel production.

Variación de rasgos del xilema secundario de Bulnesia retama (Zygophyllaceae) a lo largo de un gradiente de aridez en el centro-oeste de Argentina

The study of secondary xylem of Bulnesia retama along an aridity gradient allowed finding variations among different xylem cell types that can be used to predict tolerance of this species to aridity. The aim of this work was to carry out an anatomical description of the secondary xylem through cross sections, to analyse the variation of traits considered to be important for survival in arid environments, such as the percentage of vessels, fibres and parenchyma, fibre wall thickness, and wood density. The samples were obtained from primary branches of plants from four locations along an aridity gradient (Médanos Grandes, Bermejo, Marayes and Chepes, San Juan and La Rioja provinces, Argentina). Cross sections were observed with optical microscope and resulting digital images were analysed with ImageJ software. The results indicate that vessels are small, numerous and diagonally distributed, axial parenchyma is apotracheal diffuse. A significant increase in total fibre area and a decrease in parenchyma area with increases in aridity were observed. Total vessel area did not show any changes, while fibre wall thickness increased slightly with aridity. These traits suggest that B. retama has a highly drought-tolerant wood showing phenotypic plasticity along the aridity gradient, also registering a high-density xeromorphic wood.

First record of Dittrichia graveolens (Asteraceae, Inuleae) in Chile

Dittrichia graveolens is reported for the first time for the flora of Chile and for the Southern Cone. A brief description as well as illustrative pictures of the species and the habitat are provided. Furthermore, we present a map of the site where the population was found and a short key to the species of Dittrichia present in Chile. Insights about its potential invasiveness are discussed.

First record of the genus Cryptotaenia (Apiaceae, Oenantheae) in Colombia

Cryptotaenia japonica Hassk., a native species of Eastern Asia, is reported for the first time for the flora of Colombia. This taxon is easily recognized by its ternate leaves, rhombic leaflets, leaf margins irregularly serrate, cymose inflorescences, irregular rays and pedicels, white petals, cylindric stylopodium, erect stiles, and oblong fruits with five ribs. To date, this species has been recorded only in one locality in Cundinamarca department. A neotypification of C. japonica is proposed and keys for the genera of the tribe Oenantheae present in Colombia, and the species of Cryptotaenia s. str., are presented. Additionally, we report for the first time the family Empididae (Diptera) as floral visitor of this species.

Morfología comparada de diez taxones del género Celtis (Cannabaceae) del Cono Sur Sudamericano

The genus Celtis L. (Cannabaceae) comprises around 73 species distributed in temperate and tropical regions of both hemispheres. Most South American species belong to the subgenus Mertensia Planch., and they are characterized by showing high morphological plasticity. A recent taxonomic revision of this group was carried out with an excessively reductionist criterion regarding the number of accepted species and that does not clearly reflect the morphological differences among them. In order to contribute to the correct delimitation of the specific entities, a morpho-descriptive approach is presented for ten taxa of the genus Celtis (C. brasiliensis, C. chichape, C. clausseniana, C. fluminensis, C. pallida var. pallida, C pallida var. discolor, C. serratissima, C. spinosa, C. spinosissima and C. tala) growing in South American Southern Cone. The morphology was analyzed through the use of a stereomicroscope and/or the tpsDig program for digital images of specimens. As a result, a key is provided for the determination of the aforementioned species and a detailed morphological description of the vegetative (habit, bark, branches, spines, brachyblasts, indumentum and leaves) and reproductive structures (inflorescences, flowers, fruits and endocarp -pyrene-). In addition, a specimen collection guide is proposed with a list of the main morphological characters that should be observed in the field, to facilitate future identifications.

Malpighiaceae de Colombia: Patrones de distribución, riqueza, endemismo y diversidad filogenética

Malpighiaceae constitutes a family of 77 genera and ca. 1300 species, distributed in tropical and subtropical regions of both hemispheres. They are mainly diversified in the American continent and distributed in a wide range of habitats and altitudinal gradients. For this reason, this family can be a model plant group to ecological and biogeographical analyses, as well as evolutive studies. In this context, an analysis of distribution, richness, endemism and phylogenetic diversity of Malpighiaceae in natural regions and their altitudinal gradients was undertaken. Malpighiaceae are represented in Colombia by 34 genera and 246 species (19.1% of endemism). Thus, Colombia and Brazil (44 genera, 584 species, 61% of endemism) are the two richest countries on species of this family. The highest species richness and endemism in Colombia is found in the lowlands (0-500 m a.s.l.: 212 species, 28 endemics); only ten species are distributed on highlands (2500-3200 m a.s.l.). Of the Malpighiaceae species in Colombia, Heteropterys leona and Stigmaphyllon bannisterioides have a disjunct amphi-Atlantic distribution, and six other species show intra-American disjunctions. Both richness and endemism decrease with altitude (y = -0.061x + 173.57; R2 = 0.82; y = -0.009x + 27.76; R2 = 0.95, respectively). Amazonia (116 species, 4 endemics) and the Andes (89 species, 23 endemics) exhibit the highest richness among the family. In Colombia, 15 of the 19 clades among the family are represented, where the most diversified are the Stigmaphyllon clade (5 genera, 48 species, 10 endemics), the Byrsonima clade (3/39/5) and the Hiraea clade (3/31/9). The relationship of phylogenetic diversity with altitude is similar to the pattern of specific richness by altitudinal interval. Amazonia, Orinoquia, and Magdalena Valley show highest phylogenetic diversity. These results, combined with those of other highly diversified biological groups in the country, could be important to define and delimitate new priority areas for conservation in Colombia.