If you do go looking, you will find similar Euphorbias under these names
E. polygona
E. anoplia
E. horrida
But the story behind the banner is a little more complicated than that. The ones in the pictures are hybrids, which you aren't likely to find in stores.
These plants are dioecious (separate male and female individuals, like humans) so they can't self-pollinate... those three Euphorbias were growing side by side around the time I collected the original seed.
It's much more interesting to grow these plants from seed than from cuttings, because you know the offspring will be different from the mother plant, guaranteed.
Here she is doing her girly thing after our first fall shower.
)
