Trying to isolate the actual specific range of native plants has been challenging. This amazing site is an excellent resource for determining where the plants are growing now. The photos and other information are extremely useful identification guides, as well. And the site is fun just for the photos alone!
Here are some example links to plants I am growing from seed that gives clarity on where they really are from:
Erigeron speciosus–I even have a photo on this page
Erythranthe guttata–formerly Mimulus guttata
All of the above appear to be native to Seattle, so I feel good about adding them to the garden here.
This milkweed is not native to Seattle, so I should consider these an alien ornamental in my garden.
The seeds that are germinating so far (estimated quantity in parentheses): Erythrante guttata ( 100); Achillea millefolium (50); Collomia grandiflora (30); Lupinus bicolor (4); Asclepias speciosa (50);
Erythranthe guttata–older seedlings 
Erythranthe very small seedlings 
Asclepias speciosa–older seedlings 
A. speciosa juts germinated 
More A. speciosa 
A. speciosa just breaking ground 
Blue rye grass germinating 
Achillea millefolium 
Lupinus bicolor 
Collomia grandiflora