The main types are ...Spike, Raceme, Panicle, Umbel, and Corymb.
SPIKE: An elongated type of inflorescense in which each flower is SESSILE, ie attached to the stem directly without a pedicle [flower stem].
RACEME: An elongated type of inflorescense with induvidual flower attached to the central stalk by a flower stem [pedicle].
PANICLE: A type of inflorescence in which the main flower stalk is branched a number of times into more flower stalks, i.e., it is a branched raceme. Each flower is attached to its stalk by a flower stem, a "pedicel".
UMBEL: A type of inflorescence in which each pedicel, i.e., each flower stalk, grows upward and outward from one point in the same manner the spokes of an umbrella spread upward and outward from the umbrella main stem. The resultant flower cluster has a rounded top.
CORYMB: A type of spreading inflorescence in which each flower stem or "pedicel, originates from a different point on the main flower stem producing a flat-topped flower cluster. whereas Umbels have pedicels which originate from the same point, as umbrella spokes do.