Fotorealistic flower in photoshop

Create a new document 1200x1200 in Adobe Photoshop. I will create 1200/1200 300 dpi RGB document, but you may to use a different size.

Go to Filter> Render> Clouds, then apply Filter>Render>Different Clouds and Filter>Blur>Motion Blur.

Create a new layer (Ctrl+Shift+N), then using Rectangular Marquee tool make selection and fill it with yellow:

Send layer backward, then change Blending Mode of texture layer to linear Light.

Make selection of yellow rectangular, then invert selection and press Del.

Copy yellow rectangular and change the Blending Mode to overlay.

Merge layers (except background) and apply Warp.

Copy and rotate flower petal.

Merge layers, then copy once again, rotate.

In new layer create elliptical selection, fill it and add volume with layer style

Good luck!