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).
Division: Vegetative propagation technique that consists in cutting the whole of the roots, the rootstalk (or rootstock), tuber or other belowground structures into two or more parts. As a rule, any plant with more than one stem can be propagated by division (vertical cut of the rootstalk).