It is adorable! And a riddle that wouldn't let me sleep until I solved it. I tried and tried.... and I think I found it! (or at least my results looks similar ^^)
I think goldfishpollywog was right. Its just not number 430 but number 426. I think the center is made with this cluster stitch and the boarder with the same stitch, just not in a cluster. Its basically a halfdouble crochet that is pulled really high.
Here is my result:
The center is made of 4 clusters of 5 stitches each, with 4 ch in between. The "petals" are 10 (really loose and high) hdc in the 4 ch of the row 1. (one petal has only 5 stitches, I hoped that you could see the stitches better that way)
Now I suck at crocheting loosely so its not as neat as it might be and I guess in your example the stitches are pulled even higher then mine (they are about 4 ch high) but they are really fluffy and not twirled like dc or tc would be.