Any 8-petaled flowers?

Of plants I’m familiar with, dogwoods are four-petaled, daylilies & irises have three-point symmetry (usually six petals), the rose family (including pome trees & stone fruit trees) & the oxalis have 5 petals (or a multiple of 5).

Are there any flowers known for having eight petals–say with four-point symmetry but more than four petals?

[Yes](www.maa.org/mathland/ mathtrek_06_05_06.html), for example Cosmeas and some [Rudbeckias](http://www.robsplants.com/ plants/RudbeTrilo.php) and Coreopsis