At 1 cm diameter, it's largely a tribute to how shallow DOF gets for small subjects.
The EXIF data says that these were shot at f/8 on a Panasonic DMC-FZ7.
Using the standard formulas for DOF of an f/8 image on a 5.75 x 4.31 mm sensor, total DOF is only about 0.4 mm. That's about enough to encompass the tips of the yellow parts and whatever parts of the petals happen to lie in the same plane.
Stopping down really isn't going to help either. f/8 on that size sensor is equivalent to about f/50 on 35-mm film and f/30 on most DSLR's. It's already small enough that diffraction is starting to kick in. Starting from this point, making the aperture smaller would make the fuzzy bits sharper, but the sharp bits fuzzier. Changing sensor size won't help either, since DOF and diffraction scale together.
This DOF problem is fundamental physics of ordinary lenses.
There are some technical tricks to attack it. One of them is focus stacking, with multiple frames and an ordinary lens. Another, given a lens that will tilt, is to tilt the plane of focus to line up better with the subject (
Scheimpflug principle). Then there are some really exotic techniques like "
wavefront focusing", which uses strange optics to scramble the image followed by digital processing to make it look normal again, but with increased DOF.
In daily practice, the most practical attack may be artistic: choosing a subject and composition where the sharp bits are so interesting that either nobody is bothered by the fuzzy bits or best of all where the fuzzy bits complement the sharp bits and make them look even better. No easy trick, in either case!
The flower is something in the Aster group, but I can't get more specific than that.
--Rik
