MASTERJEE CLASSES Inflorescence is the arrangement and distribution of flowers on the shoot system of a plant. The axis of the inflorescence is called CONCEPT peduncle, whereas the stalk of individual flower is called pedicel. A INFLORESCENCE flattened peduncle is known as receptacle. Inflorescence is of five types-solitary,racemose,cymose,mixedandspecial. MAP Compound racemose Compound racemose inflorescence is an indefinite or indeterminate inflorescence in Solitary which the peduncle isbranched repeatedly once or twice in a racemose fashion. It is of following terminal types– Single flower occurs on Solitary (a)Compound raceme or panicle, e.g ., goldmohur, the terminal part of a Flowers occur singly or are Cassiafistula,Yucca. branch,e.g .,poppy. separated from other flowers (b)Compound spike or spike of spikelets, e.g. , wheat. of the same plant by (c)Compoundspadix,e.g .,coconut,date,banana. vegetativeregions. (d)Compoundcorymb,e.g.,Pyrus ,cauliflower. (e)Compound umbel, e.g. , Daucus carota , fennel,Coriandrumsativum . Solitary (f) Compound capitulum, e.g., axillary Echinops. Single flower occurs in the axil of a leaf, e.g., Petunia,Chinarose. Solitary axillary Racemose It is an indeterminate inflorescence which shows indefinite growth. The Catkin arrangement of flowers is either Dichasial acropetal (vertical orientation of cyme Polychasial cyme axis) or centripetal Cymose (horizontal orientation ofaxis). A determinate inflore- Spike scence in which the tip of main Raceme axis terminates in a flower and further Umbel Helicoid growth continues by one or more lateral cyme Cymose branches. The arrange-ment of flowers is head eitherbasipetal (vertical orientation Simple Raceme of axis) or centrifugal racemose (horizontal orientation of Peduncle is elongated having Simple racemose inflore- axis). pedicellate flowers in an acropetal Cymose scence is an indefinite fashion, e.g., Lupinus, Raphanus, inflorescence in which Linaria. head the peduncle is Sessile or subsessile flowers unbranched. are borne centrifugally Spike around a receptacle, e.g., Scapigerous An elongated peduncle bears sessile Albizzia, Anthocephalus Umbel flowers in an acropetal fashion, e.g., cadamba,Acacia. Head All the pedicellate flowers arise from a single Achyranthes, Callistemon, Adhatoda The leafless flowering axis point in a centripetal fashion. The peduncle is vasica. known asscape bears clusters verymuchreduced,e.g.,Hydrocotyle,Prunus . of flowers that form a head which is covered byspaths , Spikelet Biparous or e.g.,Alliumcepa. Corymb Spikelets are small and few flowered Dichasial cyme The main axis is comparatively short, and the spikes which are surrounded at the eduncle A terminal flower is subtended t peduncle lower flowers have much longer pedicels than base by two scales or glumes,e.g. , by two lateral branches which theupperonessothatalltheflowersarebrought rice,bamboo,oat,etc. ith long p ith shor also end in flowers.The process is moreorlesstothesamelevel,e.g.,Iberisamara . W W repeated. Inflorescence axis is Catkin multipodial,e.g.,Spergula, Multiparous Corymboseraceme Pendulous spike which bears naked Stellaria media, or Polychasial cyme The young flowers appear to be arranged like a pistillate or staminate flowers, (but Clerodendrum. More than two lateral branches corymb but in mature state the longer pedicels not both) e.g.,mulberry, poplar, Salix , continue the growth of of the lower flowers do not bring them to the Quercus. inflorescence when the parent levelofupperones,e.g. ,mustard. axis ends in a flower, e.g., Uniparous or Hamelia, Calotropis, Capitulum Spadix ened Spike with fleshy peduncle and Asclepias. tt The flattened receptacle bears numerous sessile Monochasial cyme and small florets(ray florets and disc florets) in a having both male and female flowers. peduncle A single lateral branch arises from the ith fla It is surrounded by a large green or W centripetal manner,e.g., Zinnia, Sunflower, Cosmos . peduncle of old flower which terminates coloured bract calledspathe, e.g ., in a flower. The lateral branch also palm,Colocasia,Musa . terminatesinaflower.Itisoftwotypes: (a)Helicoid cyme – All the flowers are borne Cyathium on the same side forming a sort of helix, e.g., The inflorescence looks like a Drosera,Begonia,Myosotis. flower. The bracts or the involucre (b)Scorpioid cyme - Flowers are become fused to form a cup shaped Hypanthodium alternately borne on both the sides, structure. The inflorescence contains It has a flask-shaped fleshy e.g., Tecoma, Ranunculus, pedicellate, achlamydeous, unisexual receptacle which possesses a Heliotropium. flowers of both the types, male and narrow apical opening guarded by female. The cup encloses a single hairy structure. The receptacle bears female flower surrounded by a male flowers towards the pore and large numberofmaleflowers. female flowers towards the E.g., Euphorbia Hypanthodium base. E.g., Ficus religiosa, Mixed pulcherrima. Ficuscarica. Two or more types of inflorescences get mixed up to form a mixed inflorescences. It is of followingtypes: (a)Panicleofspikelets,e.g .,oat,rice. Cyathium Verticillaster (b)Corymb of capitula, e.g ., Ageratum Verticillaster conyzoides. Two dichasial cyme inflore- (c) Umbel of capitula, scences develop from axil of racemeofcapitula. opposite leaves. They together (d)Thyrsus, e.g. , Special form a false whorl around the grapevine. node,e.g.,Ocimum,Leucus ..