different herb species - do they cross?

I wonder were I can get good information about seed saving for herbs. Say I want to grow various angelicas - do they cross? Or various basil, or encinaceas etc...

I seek promiscuous pollination in everything that I grow. I believe that it produces stronger plants. I like the variety. I like that local-adaptation is easier with more starting varieties.

The definition of species, includes the idea that if two herbs can't produce fertile offspring via pollination then they are not the same species. There are about 60 species of angelica. There are about the same number of basil species, and inter-species hybrids are common among the basils. So some varieties of basil might cross with some other varieties, but doing the research for even determining what species you are growing is super cumbersome, so you might as well plant them anyway and see what happens.

Basils won't be crossing with angelica or echinacea.

Different species of medicinal plants have slightly different properties. But then - maybe the fact that we are in Australia and our soild and our climate makes more difference to weather I take American or European goldenrod....With other plants it might be different.