A flower is a highly modified shoot (or floral axis) bearing one or more carpels or one or more stamens or both and usually one or two series of perianth parts.
Part of Flower
The branch on which flower is born
If pedicel is present
If pedicel is absent
If short pedicel is present
A Special leaf which bears flower on a bundle of flower in its axial
If bract is present
If bract is absent
Flower with both calyx and corolla
Sepals, petals both are absent
When either stamen or carpel is absent.
When stamen or carpel both are present.
A flower can be divided into similar halves in more than one plane
If a flower can be divided into equal halves in only one plane
Insertion of Flower:
Thalamus may be convex or flattened or cup-shaped and insertion of floral leaves on it varies
Thalamus is convex on conical and ovary is at the top, while sepal, petal, stamen are lower than ovary (ie ovary is superior.)
The thalamus is a flat disc-like or cup-shaped, the Gynoecium is located at the center and other floral leaves ie calyx, corolla, androecium arise from the margin of disc or cup. The gynoecium is half superior.
In some flowers, the thalamus is cup-shaped; it grows upward and completely surrounds the ovary and become fused with it. The sepal, petals, and stamen are inserted on the top of the ovary. The gynoecium is inferior.
Colour of Flower:
It can be white, pink, red, blue, etc.
- The sepals, the outermost whorl, together are called the calyx.
- In the flower bud, the sepals tightly enclose and protect the petals, stamens, and pistil from rain or insects. The sepals unfurl as the flower opens and often resemble small green leaves at the flower’s base. In some flowers, the sepals are colorful and work with the petals to attract pollinators.
If sepals are free from one another
Sepal fall off as soon as flower ripe as in poppy
Sepal fall off when the flower wither as in Buttercup
If sepal remains in place even after the fruit is formed as in pea, rose, cotton, etc.
If sepals are colored like petals
If sepals are below ovary
If sepals are above ovary
- Petals, the next whorl, surround the stamens and collectively are termed the corolla.
- Many petals have bright colors, which attract animals that carry out pollination, collectively termed pollinators
Calyx form a tube and the corolla consist of fine petal having very long claws the limbs of petals spread out above the tube at right angles to the claws as in dianthus, etc.
Petals five in number. They have a very short claw or none at all, and spread irregularly outwards, as in rose, etc.
Corolla consists of four clawed petals, arranged in form of a cross as in crucifer.
Corolla consists of five petals, three free, two fused, upper is called standard as in pea, etc.
Petals united and a like
Petals united to form a tube as in sunflower.
Petals unite to form bell shape structure.
Petal unites to form funnel shape structure.
Petal unites to form wheel shape structure.
Petal unites to form two lips.
Petal unites to form a long tubular structure called the spur.
In some flowers, small outgrowth and ligules are developed in a circle on corolla or perianth. These may be free or united, are known as the corona.
It is the third whorl of flowers consisting of stamens.
The number of stamens:
1,2,3,4,5 or more than 5
Tetra-– , Penta–, etc
Free or Fused:
If Free (Polyandrous)
- Stamen 4, 2 long, 2 short in a single whorl
- Stamen 6, 4 long, 2 short and in two whorls.
- It may be adelphous or syngenesious
Stamen unit at filament into single group
Stamen unites at filament into two groups.
Stamen unites to form many groups.
Stamen unites by their anther, the filament if free.
Stamen unites by anther and filament.
Epipetalous or antipetalous:
Stamens fused to petals
Stamen fused to perianth.
Stamen fused with the gynoecium
Filament long, short, or flattened
Fixation of anther
No joint b/w filament and base of anther
If filament is attached to back of anther and anther is immovable.
Filament is attached to back of anther and anther is immovable.
Longitudinal transverse, porous, etc.
(Carpel, 4th Whorl)
Number of Carpels
Consist of one carpel
United: (Syncarpous) or free (apocarpous)
Syn = United, kerpos = ovary
Ap = free, kerpos = ovary
If over the sepals, petals
If below the sepals, petals.
Number of Loci:
(Single = locule) = chamber of the ovary)
PLACENTATION: Attachment manner of seed to an ovary
Ovary single chambered, ovule attached to the ventral suture as in pea, gram, etc.
(Towards periphery) an ovary is compound and unilocular.
Polycarpellary, syncarpous; carpel fuse to form column eg lemon.
Ovary unilocular, placenta directly develops on the thalamus and single ovule is attached eg Anagalis
Number of the ovule in each locule
Free or united
(an Apical portion of style)
Stigma rounded and knob-like
Stigma is branched to form two lobes culled bifid. Bifid stigma indicate two carpels
Branched like a feather, as in grasses.
Long, narrow, pointed as in Berberry.
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NJMH is working as Deputy Conservator of Forests in Balochistan Forest & Wildlife Department (BFWD). He is the CEO of Tech Urdu (techurdu.net) Forestrypedia (forestrypedia.com), Majestic Pakistan (majesticpakistan.pk), All Pak Notifications (allpaknotifications.com), Essayspedia, etc & their YouTube Channels). He is an Environmentalist, Blogger, YouTuber, Developer & Vlogger.