Diathus/carnation or sweet william??

Please can someone explain the differences to me?

As I understand they are all of the Diathus family. Carnations are annual(?) and sweet williams are biannual and dianthus are perennial.

I paid a visit to a garden centre at the weekend and bought what I thougt was a dianthus (It has a tiny flower that looks like a double carnation). On the flower pot it says its a sweet william dianthus. I thought that sweet william flowers are very different to 'carnations' with many flowers on a stalk. So now I'm totally confused. CCan anyone explain?

 

I think Dianthus is just a generic name covering all flowers in the group; primula, for instance, covers many different forms of the plant.
"Pinks" also come under the dianthus heading and I wonder if that's what you bought at the garden centre. It seems early to have it in flower but all sorts of things are forced nowadays.
Some types of carnation are hardy perennials and you can get seed of a variety of sweet william which flowers in the first year of sowing so is not biennial like most varieties. It's all a bit confusing but I'm sure you'll soon sort out the differences just by growing the plants!

 

On second thoughts Ethansmum, you might have purchased a double variety of sweet william at the garden centre which is starting to flower early and has just one bloom beginning to open. Is it surrounded by what looks like a lot of closed buds?

 

Okay, I think I get it, Thanks Jack.

The leaves look almost like the 'Pinks' and the flower is just a miniature 'Pink', I guess what threw me was that it was called a sweet william ??

 

The "Wikipedia" article on dianthus says that there are about 300 species of this plant and a "Google" search indicates over a million entries. If you've got a little time to spare you might just be able to trace what it is you bought from the garden centre!

 

I've tried google images but gave up after the first 10 pages.

I think I'm going to have to admit defeat on this one, next time I'm there I'll ask. Thanks for the help