The phenomenon, though rare, may be ancient.
Tag - floral biology
Erin Zimmerman
Within a mixed species, annuals self-pollinate more than perennials
A smaller stigma-anther separation in annuals seems to indicate a genetic basis for mating system differences.
Phylogeography and reproduction modes in Limonium spp.
The genus Limonium (Plumbaginaceae) has long been recognized to have sexual and apomictic (asexual seed formation) modes of reproduction.
botanyone