How to make abstract flowers with Photoshop?

Could someone tell me how to create an abstract flower design like the one on avivadirectory.com (bottom right) ?

 

Not the best design, but could give you some ideas.

http://www.insidegraphics.com/textile_designing/photoshop_textile_arts.asp

 

They're actually called foliage. Here's a basic tutorial that I wrote that'll teach you how to make those nice vines

http://www.photoshop-tutorials.info/foliage-tutorial.html

 

Very nice tutorial, thank you.

Using this technique you can also make stuff like on aviva?

 

Yes That's just a basic tutorial. You can use it to make more swirls of course. Using the "similate pressure" ads the effect that you see.. how the lines go from thick to thin.