Inflorescences & Its Types

Inflorescence

Submitted Submitted Too; MrMr, Sultan MuhammadSultan Muhammad

Submitted Submitted ByBy; Mohammad SaifMohammad Saif

• Department: Center For Agriculture Sciences And Forestry University Of Swat

What is an inflorescence?

• In angiosperms many small flowers are borne together in dense clusters called inflorescence. OR

• The arrangement of flowers on the floral axis (Shoot system) of a plant is called inflorescence.

• Cluster of flowers ensures pollination, fertilization and thus the reproductive success of the species.

• There are many types of inflorescence. Each type of inflorescence is determined by how the flowers are arranged.

Types of Inflorescence

1. Racemose Inflorescence: In racemose inflorescence, the main axis continue to grow indifinitely until the last flower is formed at its apex. The oldest flowers are towards the base of the inflorescence and the youngest ones towards the apex.

2. Cymose inflorescence: In cymose inflorescence, the main axis soon ends in flower. One, two or more lateral branches develop below the terminal flower, each ending in a flower like the main axis. In this case the terminal flower is oldest and the lateral flowers are younger.

Racemose Inflorescences

• Typical Raceme• Spike• Catkin• Corymb• Umbel• Panicle• Capitulum

Cymose Inflorescences

• Uniparous cyme/Monochasial cyme• Biparous cyme/Dichasial cyme• Multiparous cyme.

Typical Raceme

• In typical raceme the main axis is elongated.

• The main axis bears laterally a number of flowers.

• Each flower has a pedicel or stalk.

• eg. Cassia fistula.• Racemose.

Raceme

Typical Raceme

• Cassia fistula is widely grown as an ornamental plant.

• It blooms in late spring.• Flowering is profuse, with

trees being covered with yellow flowers, many times with almost no leaf being seen.

Cassia fistula

Spike

• The main axis is elongated like raceme.

• Individual flowers are sessile (without pedicels).

• eg. Bottle brush.• Racemose.

spike

Spike

• Bottle brush are mostly found in the more temperate regions of Australia.

• It typically favour moist conditions.

• When planted in gardens thrive on regular watering.

Bottle Brush

• It is a spike.• Unisexual flowers i-e

bears only staminate(having stamens) and pistillate(having pistels) flowers.

• Sessile flowers.• Hidden by bract.• eg. Mulberry, Willow.• Racemose.

Catkin

• Many trees bear catkins.

• Catkin Flowers are in; • willows, • birches etc.

Willow Flower

Catkin

Corymb

• The main axis is comparitively short.

• The stalk of the lower flowers are longer than those of the upper younger ones.

• Often flat-topped.• eg. Iberis(candy tuft)• Racemose.

corymb

pedicel

Corymb

• The leaves, stem, and root are said to possess medicinal properties.

• The seeds are most efficacious.

Candy tuft

Umbel

• The main axis is shortened.

• Individual flower pedicels all originate from the same spot on the peduncle(stem).

• eg. Hydrocotyl (brahmi booti)

• Racemose.

peduncle

pedicel

Compound Umbel

• In some cases a number of umbels are present on main axis.

• Such compound inflorescence is called compound umbel.

• eg. Carrot. Compund Umbel

Panicle

• A highly branched inflorescence consisting of many, repeating units.

• Panicles can be made of many spikes, racemes, corymbs, or umbels.

• eg. Grapes, Mango, Oat.• Racemose.

A panicle of racemes

Panicle

• Grapes are a type of fruit that grow in clusters of 15 to 300.

• It can be black, dark blue and green.

Common Grape

Capitulum

• Capitulum consists of dense terminal sessile flowers (flowers which have no pedicel).

• Flowers are crowded together on a very short axis.

• It looks like a single flower.• eg. Sunflower.• Racemose.

sessile flowers

Capitulum

• Sunflower, produces a large number of sessile flowers.

Sunflower

Uniparous Cyme

• The main axis ends in flower and produce only one daughter axis.

• The daughter axis again ends in flower and give rise to one daughter axis.

• eg. Begonia, Tradescenta.

• Cymose

Begonia

Biparous Cyme

• The main axis ends in flower and prduces two daughter axis.

• Each of the two daughter axis again end in a flower and produces two daughter axis.

• Continue the branching in same manner.

• eg. Silene, Ipomea.• Cymose

Biparous Cyme

Multiparous Cyme

• The main axis ends in a flower and produce multiple axis.

• Each of it may continue the branching in the similer manner.

• eg. Euphorbia• Cymose Euphorbia

The End