All hibiscus and related genus germinated well especially Hibiscus sabdariffa that popped their roots two days after being nicked and soaked. Still waiting on Canna edulis and Prunus (these are older seeds so I'm not sure if they are viable). One of the most interesting germination habits I've ever seen are from these Tinantia erecta:
If I was formally trained, I'd probably have something more enlightening to say then cool. As it is, check out the multiple 'seed' roots.
OH performs seed surgery - scarification