Se presenta una revisión de las especies argentinas de Randia. A partir de este estudio se reconocen tres especies: R. ferox, R. micracantha y R. calycina, siendo ésta última una nueva cita para el país. Se propone excluir del país a R. armata, especie amplia y erróneamente citada para el área. Se analizaron aspectos taxonómicos, la anatomía vegetativa y morfología polínica de las tres especies. Todos los taxones son descritos y diferenciados a través de una clave dicotómica. Se incluyen además imágenes de los caracteres diagnósticos de las especies, mapa de distribución y observaciones ecológicas. Se proponen lectotipos para los nombres de los taxones Basanacantha, R. calycina y R. ferox. Randia micracantha var. glabra es tratada como un nuevo sinónimo de Randia micracantha. Se determinó que algunos caracteres anatómicos y polínicos son útiles para la diferenciación de las especies argentinas.

Randia brevituba is a new species of the Paranean region of Argentina and Paraguay. It differs from the closest species, R. ferox, which is sympatric, in having short corolla tubes of 4.7-5.4 mm in the pistillate flowers and 2.8-7.9 mm in the staminate flowers, calyx lobes varying in shape and size in the same pistillate flower, and globose fruits 14-17 mm long (versus corolla tubes of 25.0-27.0 and 22.6-34.0 mm long, respectively, calyx lobes equal in shape and size, and fruit 3-5 cm and ovoid, ellipsoid or subglobose in R. ferox). We also discuss the taxonomic concept and geographic distribution of Randia armata, and conclude that it is markedly different from R. brevituba and the other species in the Southern Cone studied here, and moreover, that it does not occur in the Southern Cone. We provide a taxonomic key to distinguish the new species from other species of Randia in the Southern Cone of America.

Editor: Maria von BalthazarPremise of research. The primary goal of this study is to describe the colleters on vegetative and reproductive organs in the Spermacoceae tribe and to characterize their morphoanatomy, their distribution, and some functional and evolutionary aspects.Methodology. The anatomy, development, and vascularization of colleters from 28 species were studied using standard light and scanning electron microscopy based on fresh and fixed material. Our results are interpreted within the framework of recent molecular phylogenies.Pivotal results. Standard-type colleters were found on stipules, calyx, and bracteoles, and they were also found on underground buds in five species of Galianthe. Six species have green colleters, and two have vascularized colleters. We discuss previously unknown functional aspects based on the Staelia glandulosa colleters and propose a new term: long-lived colleters.Conclusions. This article describes the anatomy of colleters in the Spermacoceae tribe of the family Rubiaceae in detail. The presence of underground colleters in Galianthe grandifolia is confirmed and extended to other species of the genus. Vascularization is recorded for the first time in colleters of Mitracarpus and Staelia. This study provides data about the type, distribution, and anatomy of colleters in Spermacoceae, contributing important information for ongoing phylogenetic studies in the tribe. The proposal of a new functional type of colleter based on anatomical, morphological, and ecological aspects, named long-lived colleter, reflects the need to perform further comprehensive studies based on multidisciplinary approaches.

Abstract―Randia heteromera is a new species described based on studies of taxonomy and vegetative anatomy (leaf, stipule, and colleters). This species is illustrated and diagnosed in comparison to the other four similar species of Randia in the Southern Cone of America. The species grows in areas of humid forests, locally known as the humid Chaco in the southern part of its distribution (Argentina and Paraguay), and in seasonal forests in the northern part, in northeast Paraguay and the south of Mato Grosso do Sul in Brazil. We present a key to distinguish R. heteromera from the other species of the Southern Cone of America. The species was also compared with similar taxa, Randia nitida or R. hebecarpa, occasionally used to identify material from the Southern Cone of America. A distribution map is provided. The anatomical data studied had a taxonomic value at the species level. In addition, based on the leaf anatomy studies carried out in the present study and in previous studies, three new types of vascular tissue organization in the leaf are described for Rubiaceae.

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we conducted anatomical analysis of anthers with the aim to establish the differences in the development pattern of microsporophytes and microgametophytes between perfect and imperfect flowers in the tribe Gardenieae (Rubiaceae). The species studied were: Tocoyena formosa (monoecious with perfect flowers), Cordiera concolor, Genipa americana, Randia calycina, and Randia heteromera (dioecious with imperfect flowers). Flowers in successive stages of development were collected and fixed. The material was processed and examined using light microscopy and scanning electron microscopy. The present study revealed the stage when pollen is arrested in the functionally pistillate flowers of the dioecious taxa. Based on these observations an evolutionary sequence of changes towards the reduction of non-functional anthers in Rubiaceae is proposed. In addition, we describe and discuss characters that might be of importance in future phylogenetic studies in Rubiaceae (e.g., pollen morphology and its dispersal unit, the presence of orbicules, and a new type of placentoid).

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A comprehensive study on the fruit anatomy and development of Cordiera concolor was carried out to establish the origin of the gelatinous tissue surrounding the seeds at maturity. Cordiera currently belongs to tribe Cordiereae, forming part of the species-rich lineage called Gardenieae complex. Most genera of Gardenieae complex has many-seeded fl eshy fruits, with seeds usually imbedded in a pulp, which historically was considered of a placental nature. For the histological analyses, fruits at different stages of development were fi xed in formalin-acetic acid-alcohol and examined with light microscopy. The endocarp has no woody consistency, it is what classifi es a fruit as berry. The pericarp is differentiated into three histological zones: 1) the exocarp, formed of the epidermis and the sub-epidermal tannin cells, 2) the mesocarp, consisting of parenchyma with tannins and druses, and 3) the endocarp, derived from the internal epidermis of the ovary. The placental tissue has little development during the formation of the pericarp. We concluded that the gelatinous tissue surrounding the seeds in the ripe fruit is formed of the mesocarp and endocarp. The present results disagree with the widely accepted conception of the placental origin of the gelatinous pulp surrounding the seeds in Gardenieae Complex species.