I want to grow Dyanthus

If you mean Dianthus, the following link shows a picture of what seed head looks like
you can collect the seeds from here

thats the only way I know to grow these

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http://en.wikipedia.org/wiki/Dianthus

If the dianthus are annual ones (there are a few) then seed is the only way to grow them. The seed will store well in a paper envelope in a cool dry place or the salad section of a fridge. Sow in Spring in ordinary compost and cover the seed with grit rather than compost. they germinate within a few days.
If they are perennial dianthus, then as well as seed (which may give plants that differ from the original) you can take cuttings. Choose a non flowering shoot and pull off a piece about 2 inches long Rather like pulling a length of grass to chew!. Remove the bottom pair of leaves carefully and insert in compost in a pot and cover with a plastic bag. They take about a month to root.

ooh there you go
learn something new everyday

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Do as Owdboggy says - they are really easy from cuttings!!