The mystery seeds from last week were from the coral bean, Erythrina flabelliformis.This particular species grows in the desert Southwest.
There are several coral bean species that grow throughout the world, but they have one thing in common: the bright red seeds are poisonous.
I don't have any photographs of the plant, but Firefly Forest has a nice summary. The flowers are also brilliant red.
Seed of the Week will resume next Tuesday.