Nectarios y Vascularización Floral en especies de Piriqueta y Turnera (Turneraceae).
Boletín de la Sociedad Argentina de Botánica
Ed. Sociedad Argentina de Botánica.
Año: 2001 vol. 36 p. 47 - 68
Summary: Nectaries and floral vasculature in Piriqueta and Turnera (Turneraceae). Floral vascularization was analysed in 10 Piriqueta species and in 27 Turnera species, belonging to the nine series of the genus. Piriqueta flowers present a crown in the gorge that lacks vascularization. A ligule, located at the petal blade base, was found in T. capitata and T. panamensis; its structure is anatomically similar to the crown, and also lacks vascularization. All species have five masses of glandular tissue, deeply immersed in the receptacle, between the sepal and staminal traces. Differences among species are detected when the staminal filaments set apart of the other pieces of the floral tube. Three nectaries were found: on the tube, staminal and nectar pocket; the last one is the most differentiated. Two types of nodal anatomy are described: 1) where the peduncle and the petiole are free, being the flowers strictly axilar, and 2) with the peduncle and petiole partially or totally adnated. The epifilous flowers represent a derived condition, being axilar in their origin, because petiole and peduncle traces are independent. According to the analysed characters an evolutionary sequence is suggested, where Piriqueta would be in the lower position; in the genus Turnera, the series Sacilifoliae, Capitatae and Annulares would be the less specialised, Papilliferae, Microphyllae, Stenodictyae and Leiocarpae would be in an intermediate position, while Anomalae and Turnera would have the most derived characters of the genus.