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A DETAILED ACCOUNT ON MORPHOLOGY OF INFLORESCENCE

Definition: Inflorescence or anthotaxy is the branch or branch system bearing flowers or is the
arrangement of flowers on the floral axis
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The floral
axis of an inflorescence bearing flowers is called rachis and the stalk of the individual flower is known as
pedicel
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e
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Types: Inflorescence are mainly of 3 types, viz
(1) Indefinite/ Racemose inflorescence
(2) Definite/ Cymose inflorescence
(3) Mixed inflorescence
(1) Indefinite/ Racemose inflorescence: This type is also known as botryose
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e
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e
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This type of inflorescence again consists of:
(A) Primary axis or rachis elongated
(i)
Simple forms:
(a) Raceme: Primary axis or rachis long, bearing pedicellate flowers opening
from base to apex i
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in acropetal succession
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It is found in both
monocot as well as dicot plants
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e
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Example:
Prunus cerasus ( Rosaceae) and Cassia sp
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(c) Spike: Like raceme but flowers are sessile
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It occurs in
numerous families
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Example:
found in the families of Juglandaceae, Betulaceae etc
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Ctkin is found in some members of
Euphorbiaceae like Acalypha hispida, Aporosa sp
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It is found in members of Araceae ( species of
Colocasia, Amorphophalus etc
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(f) Locusta/ Spikelet: This is a condensed spike subtending one or few
flowers; the rachilla i
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the floral axis may be very small or long produced
beyond the glumes- the so called bracts of this inflorescence
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e
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Found in Graminae (Poaceae) and Cyperaceae
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Example:
Humulus lupulus
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Here the
primary floral axis or rachis bears secondary branches upon which flowers are
developed
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Example: Mangifera
indica ( Anacardiaceae), Litchi etc
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Here flowers are
borne in corymbose manner on the branches of the main axis or rachis
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(c) Compound Spike: When sessile flowers arise on branches on the main
axis in a spikate manner
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(d) Compound Spadix: This type is noted in Arecaceae i
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Palmea where the
axis of a spadix branches and the entire structure is covered by a stiff
boat shaped spathe
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(B) Primary axis or rachis short
(i) Simple forms:
(a) Umbel: It has a short floral axis upon which pedicellate flowers are
arranged in radiating manner, the order of development is centripetal
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(ii) Compound forms:
(a) Compound Umbel: Also known as a characteristic of family Apiaceae
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Example: species of Foeniculum,
Coriandrum etc
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Example: Mimosa, Acacia etc
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(C) Primary axis fleshy and dilated:
Capitulum/Head/ Anthodium: Here the rachis is called receptacle, it is fleshy and
dilated; the flowers are sessile and small, sometimes the marginal flowers are quite
diffetent from the central ones
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The centrally situated flowers are bisexual and known as disc
florets
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(2) Definite/ Cymose inflorescence: Here the growth of the primary axis is checked and is thereby
terminated by a flower
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(a) Solitary terminal/ axillary flower: Apical or axillary bud develops into
a single flower
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(b) Monochasium/ Uniparous cyme: The primary axis ends in a flower
and one lateral branch is produced ending in a flower and the process
is repeated
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Example: Heliotropium
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Example: Hamerocallis flava (Liliaceae)
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Example: Jasminum
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Example: Sambuscus nigra, Calotropis etc
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In this case the receptacle terminates into a
single flower (female)
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In the axils of opposite leaves at first a
dichasium is produced, then each branch passes into a
cincinnus
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Examples: Species of
Leonurus, Coleus etc
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Example: Ficus cunea
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Where the receptacle is
more or less flat with little upwardly curved margins; minute
flowers are embedded within the receptacle
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Example: Anthocephalus indica
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Example: Sunflower (Helianthus), Dahlia etc
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Examples: Ligustrum vulgare(Oleaceae)
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Example: Musa paradisiaca
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(d) Cymose corymb/ Corymbose cyme: Arranged in a corymbose manner
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(e) Thyrsus: Several clusters are arranged acropetally forming the shape of a double cone on
a raceme type of primary axis
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