This inflorescence (umbel) is characteristic of Apiaceae (Umbelliferae) family. Sometimes, the umbel is un-branched and known as simple umbel, e.g., Brahmi (Centella asiatica). Generally the umbel is branched and is known as umbel of umbels (compound umbel), and the branches bear flowers, e.g., in coriander (Coriandrum sativum), fennel, carrot, etc. Some are in compound spikes (i.e., in wheat-Triticum aestivum), others are in racemes (e.g., in Festuca), while some are in panicles (e.g., in Avena). Spikeletes are arranged in a spike inflorescence which is composed of several to many spikelets which are combined in various manners on a main axis called the rachis. In this type of racemose inflorescence the main axis remains elongated and the lower flowers are older, i.e., opening earlier than the upper ones, as found in raceme, but here the flowers are sessile, i.e., without pedicel or stalk, e.g., amaranth (Amaranthus spp.), latjira (Achyranthes aspera), etc.Įach spikelet may bear one to several flowers (florets) attached to a central stalk known as rachilla. The stalk of the individual flower of the inflorescence is called the pedicel.
The main axis of the inflorescence together with the latest axes, if present, is termed as the peduncle. When the main axis of raceme is branched and the lateral branches bear the flowers, the inflorescence is known as compound raceme or panicle, e.g., neem (Azadirachta indica), gul-mohar (Delonix regia), etc. The lower or older flowers possess longer stalks than the upper or younger ones, e.g., radish (Raphanus sativus), mustard (Brassica campestris), etc. Heads can be determinate or indeterminate.Ī many-flowered inflorescence with an indeterminate central axis and many opposite, lateral dichasia a mixed inflorescence, with determinate and indeterminate shoots.Ī determinate inflorescence with 2 dichotomous lateral branches and pedicles of equal length.Ī determinate cyme in which the branches develop only on 1 side, due to the abortion of opposing paired bud, the inflorescence thus appearing simple.Ī tight, modified helicoid cyme in which the pedicels are very short.Ī zig-zag determinate cyme with branches developing alternately on opposite sides of the rachis, due to abortion of opposing paired bud.In such cases the main axis remains elongated and it bears laterally a number of stalked flowers. Umbels can be determinate or indeterminate.Ī branched umbel, with primary rays arising from a common point, and secondary umbels arising from the tip of the primary rays.Ī dense vertically compressed inflorescence with sessile flowers on a receptacle and subtended by an involucre of phyllaries, characteristic of the Asteraceae.
Northern Ontario Plant Database Inflorescence TypesĪn elongate, unbranched, indeterminate inflorescence with sessile flowers.Ī small spike, characteristic of grasses and sedges.Īn elongate, unbranched, indeterminate inflorescence with pedicelled flowers.Ī flat-topped raceme with elongate pedicels reaching the same level.Ī flat-topped or rounded inflorescence with the pedicels originating from a common point.