Abstract 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 fleshy 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 fixed in formalin-acetic acid-alcohol and examined with light microscopy. The endocarp has no woody consistency, it is what classifies 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.

Abstract 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).

A revision of the Argentinian species of Randia is presented. According to this study, three species are recognized: R. ferox, R. micracantha and R. calycina, the latter being a new record for the country. It is here proposed exclude Randia armata from the country, a species that is widely and erroneously cited for the area. Taxonomic aspects, vegetative anatomy and pollen morphology of the three species are analyzed. All taxa are described and differentiated through a dichotomous key. Images of diagnostic characters, a distribution map, and ecological observations are included. Lectotypes for the taxon names Basanacantha, R. calycina and R. ferox are proposed. It is proposed to Randia micracantha var. glabra is treated as a new synonym for Randia micracantha. It was determined that certain anatomic and pollen characters are useful for differentiating the species occurring in Argentina.

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.