Type of inflorescence in which all pedicles (floral stalks) eradiate from a common point. E.g., geranium, gardenia. One can also say the umbel is a raceme whose axis did not elongate: the younger flowers are in the center and the older gradually distal. (Also see Raceme, Inflorescence).
Undulated
Leaf or petal with wavy margin. The term is not applied to serrated or toothed margins.
Unisexual
Monoecious or Dioecious plants in which the flower are male or female; flower that is not hermaphroditic, but is either male or female. (compare with Hermaphrodite).
Flower: Generally the most visible characteristic of a plant, the flower is an organ made of very specialized parts, related with sexual reproduction. Some plants produce flowers with only male organs (stamens) or female organs (pistils). These parts are generally surrounded by a ring of colored petals and green sepals. In the majority of plants, a flower has both male and female organs; however some species have male flowers and female flowers, like the begonia: the male flowers have a series of brightly colored petals with stamens full of pollen, whereas the female flowers have a large winged sac of seeds, behind the petals.
