NEET Biology Notes Morphology of Flowering Plants Inflorescence
The arrangement of flowers on the floral axis is termed as inflorescence. The axis of inflorescence is called peduncle. These are of basically four main types:
Classification of inflorescence
- Racemose Inflorescence
In racemose type inflorescence, the main axis continues to grow and the flowers are borne laterally in an acropetal succession (the older flowers are found towards the base and younger ones at the apex) or centripetal (older towards periphery and younger towards centre)
e.g. radish and Delphinium.
- Cymose Inflorescence
Cymose or determinate or definite inflorescence includes uniparous or monochasial cyme and biparous or dichasial cyme. In uniparous or monochasial cyme, the main axis ends into a flower and produces only one lateral branch at a time ending into flower. It can be either scorpiod monochasial,
e.g. Ranunculus, Tecoma or helicoid monochasial,
e.g. Drosera, Begonia. In biparous or dichasial cyme two flowers arise from the same point and again central flower is most mature with two lateral shoots.
e.g. Ixora and Mussaenda.
- Mixed infloresence
It has combination of cymose and racemose characters.
e.g. cymose, umber, thyrsus.
- Special Type of Inflorescence
It mainly involves highly modified and densdely crowded inflorescences. The special type of inflorescence can be divided into following types:
- Cyathium Inflorescence
It is the characteristic feature of Euphorbia, in which single female flower present in centre is surrounded by a number of male flowers inside a cup-shaped involucre which consists of whorl of bracts.
- Hypanthodium Inflorescence
It is the characteristic feature of family-Moraceae, e.g. fig, peepal, etc., in which cup-shaped cavity with an apical opening or ostiole is formed by a fleshy receptacle, guarded by inwardly projecting hair and bear flowers on the inner wall of the cavity. The female flowers are present at the base and male flowers at the opening.
- Verticillaster Inflorescence
It is the characteristic feature of tulsi (Ocimum) belongs to family-Lamiaceae or Labiatae. Here, flowers are arranged in two opposite cymose groups on each node.