You want what is known as a dichotomous key. Each step offers you two choices and you refine from there. I didn't find any online dichotomous key's for NorCal vascular plants online though, but it was a cursory look. The gold-standard plant identification book for California is called the Jepson Manual. It's available online at: http://ucjeps.berkeley.edu/interchange/I_treat_indexes.html but unfortunatly, it isn't presented as a dichotomous key. I'm not sure it would really do you any good though as indoor plants are usually from a nursery and aren't really likely to be native to the area. So you'd probably be better served by a generic plant identification guide. The best looking one I've found so far is Neoflora: http://www.neoflora.com/search.html Hope that helps. Judah Canfield, Joel wrote: > I'm looking for an online tool a la 'what the font' that'll ask me a > series of salient questions to identify the mysterious plants around our > office (people bring 'em in randomly, move 'em from place to place, then > leave and nobody knows what most of 'em are.) > > I used to be in landscaping, so I can identify most SoCal outdoor > plants, but these are NorCal indoor plants, and I'm persistently > stumped.