Along with hosting Tweeters at the UW, there is another great resource that the Burke Museum offers - the WTU Herbarium Image Collection.
I've been using the thing for years, having stumbled upon it somehow in my internet searches, but I thought I'd let Tweeters know about it, just for the record. In case you didn't know.
The site is a very well organized collection of photos and information (taxonomic details, range info, etc.) about Washington State native plants. While not exactly a field guide, if you know your plants in general, it is a great resource to confirm ID and get more info on your vegetable of interest, including Lichens. You can search with common names, or them fancy scientific names by genus or family. Easy to use. Oh sure, I can use a key, but I like lookin' at photos too.
For those of you who just can't live without them, they also got a new app for your portable gizmo, the "Washington Wildflower App" with 870 flowering plants on it. I find such things irritating and hard to see in daylight glare, but you might love it. You can confirm that, yes, that Purple Finch was eating Pacific Crabapples (Malus fusca). Or whatever.
Just Sayin'Jeff Gibson