The questionable relationship of Montinia (Montiniaceae): Evidence from a floral ontogenetic and anatomical study

The systematic position of Montiniaceae remains uncertain: a relationship w ith Cornales has been suggested on phytochemical and embryological evidence , while molecular data point to a relationship with Solanales. We investiga ted the floral development and anatomy of the South African Mantinia caryop hyllacea to add a new set of characters for clarifying the systematic posit ion of the family Montiniaceae, Pistillate inflorescences show a higher deg ree of reduction than staminate, with flowers set terminally on short later al branches. Flowers have an irregular initiation sequence, with frequent a bortions of organs. In Montinia, petals grow rapidly, and no zonal growth t akes place. The gynoecium develops as a pit surrounded by a girdle. Placent ation is basically parietal and becomes axillary by the postgenital fusion of placental lobes; unitegmic ovules are arranged in two parallel rows with adjacent ovules partly overlapping each other. Unisexuality is respectivel y attained at the stage of anther development and carpel initiation. The fl oral anatomy of pistillate and staminate flowers is illustrated and discuss ed. Observations on Montinia are compared with data of taxa from Saxifragac eae sensu stricto, Cornales, and Solanales. The absence of sympetaly in Mon tinia is discussed, Morphological and anatomical evidence points to a high similarity with Escalloniaceae. Although a position in the asterids is most probable, there is little support For the relationship with Solanales indi cated by molecular data.