INTRODUCTION

What does it take to recognize a family such as Gentianaceae? This is both an evolutionary biological question and one of perception and emphasis. Tracing back to the descriptor of Gentianaceae, Antoine Laurent de Jussieu (1789), gentians were distinguished as the Natural Order “Gentianeae”, one of 15 such orders in Jussieu's class VIII, “Dicotyledones monopetalae, corolla hypogyna”. According to Lindley (1853), Jussieu usually derived the names for his Natural Orders from genera deemed well representative in their general structure. We therefore have Gentianaceae from Linnaeus's Gentiana, defined by being dicotyledonous, sympetalous, and hypogynous. However, in the twenty-first century it is easy to see that many angiosperms, both those phylogenetically close and those phylogenetically distant from each other, could fit this bauplan. In one such example, Jussieu included Mitreola and Spigelia in Gentianaceae; in another, he included Potalia. These opinions were both pre-evolutionary (Darwin, 1859) and pre-phylogenetic (Hennig, 1966; Kluge & Farris, 1969), and were therefore based on different emphases of perceived morphological similarities and differences. In the first case, the hemi-apocarpous nature of the Mitreola and Mitrasacme gynoecium (Endress et al., 1983; Conn et al., 1996) matched the nascently apocarpous but postgenitally fused ovaries of many Gentianaceae (Padmanabhan et al., 1978). Spigelia does not display this trait, but it does have generalized sympetalous and hypogynous flowers.