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Essential Parts of Flower
Androecium: Third whorl of flower is the male reproductive part of the flower. It is composed of stamens(microsporophylls). Each Stamen consist of 3 parts, a. Filament b. Anther c. Connective
Anther: Upper swollen part with mi-crosporangia.
Filament: Stalk of stamen
Connective: Tissue connecting anther lobes with filament
Anther typically contains two com partments called thecae (singular theca). Each theca consists of two microsporangia. Two microsporangia fused to form a locule.
Sterile stamens are called Staminodes. Example: Cassia.
Distinct: stamens which do not fuse
to one another. Free: stamens which
do not fuse with other parts of flower. Apostemonous:
flowers with stamens that are free and distinct.
Refers to the stamens fusing among themselves or with other parts of flower. Two types
Connation and 2. Adnation
1. Connation: Refers to the fusion of stamens among themselves. It is of 3 types. a. Adelphy. b. Syngenecious. c. Synandrous.
a. Adelphy: Filaments connate into one or more bundles but anthers are free. It may be the following types.
1. Monadelphous: Filaments of stamens connate into a single bundle. Example: malvaceae (chinarose,cotton).
2. Diadelphous: Filaments of stamens connate into two bundles.
Example: Fabaceae, pea.
3. Polyadelphous: Filaments connate into many bundles. Example: Citrus, Bombax
Syngenesious: Anthers connate, filaments free. Example:
c. Synandrous: Filaments and anthers are completely fused. Example: Coccinea.
2. Adnation: Refers to the fusion of stamens with other floral parts. Epipetalous (petalostemonous): Stamens are adnate to petals .Example: brinjal,Datura.
a. Episepalous: stamens are adnate to sepals. Example: Grevillea (Silver oak) Stamen
b. Epitepalous Petal ( epiphyllous ) : stamens are adnate to tepals. Example: Asphodelus, Asparagus.
c. Gynostegium:Connation product of stamens and stigma is called gynostegium. Example: Calotropis and Orchidaceae.
d. Pollinium: Pollen grains are fused together as a single mass
1. Didynamous (di-two, dynamis-strength): Four stamens in which two with long filaments and two with short filaments. Example: Lamiaceae, Ocimum. If all four stamens are in two equal pairs then the condition is called didynamous.
2. Tetradynamous(tetra-four): Six sta-mens of which four with long filaments and two with short filaments. Example: Brassi-caceae, (Brassica).
3. Heterostemonous: stamens are of different lengths in the same flower. Example: Cassia, Ipomoea.
1. Inserted: Shorter than the corolla tube and included within. Example: Datura.
2.Exserted:Longer than the corolla tube and project out.Example: Mimosa, Acacia arabica
The number of whorls of stamens present in a flower is called stamen cycly. Two major types are 1.uniseriate,a single whorl of stamens and 2.biseriate,two whorls of stamens.
1. Monothecal: One lobe with two microsporangia. They are kidney shaped in a cross section. Example: Malvaceae
2. Dithecal: It is a typical type,having two lobes with four microsporangia.They are butterfly shaped in cross section. Example: solanaceae.
a) Haplostemonous: stamens are uniseriate and equal in number to the petals and opposite the sepals (antisepalous)
b) Obhaplostemonous: Stamens are uniseriate, number equal to petals and opposite the petals (antipetalous)
c) Diplostemonous: Stamens are biseriate, outer antisepalous, inner antipetalous. Example: Murraya.
d) Obdiplostemonous: Stamens are biseriate, outer antipetalous, inner antisepalous.Example:Caryophyllaceae.
e) Polystemonous: Numerous sta-mens are normally many more than the number of petals.
1. Basifixed:(Innate) Base of anther is attached to the tip of filament. Example: Brassica, Datura.
2. Dorsifixed: Apex of filament is attached to the dorsal side of the anther. Example: Citrus, Hibiscus.
3. Versatile: Filament is attached to the anther at midpoint. Example: Grasses.
4. Adnate: Filament is continued from the base to the apex of anther. Example: Verbena, Ranunculus, Nelumbo
It refers to opening of anther to disperse pollen grains.
i Longitudinal: Anther dehisces along a suture parallel to long axis of each anther lobe. Example: Datura, chinarose, cotton.
ii Transverse: Anther dehisces at right angles to the long axis of anther lobe. Example: Malvaceae.
iii Poricidal: Anther dehisces through pores at one end of the thecae. Example: Ericaceae, Solanum, potato, brinjal, Cassia.
iv. Valvular: Anther dehisces through a pore covered by a flap of tissue. Example: Lauraceae, Cinnamomum.
It shows the position of anther opening relative to the anther of the flower.
1. Introrse: Anther dehisces towards the center of the flower. Example: Dianthus.
2. Extrorse: Anther dehisces towards pe-riphery of the flower. Example: Argemone.
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