I spotted this nasty invasive in San Francisquito Creek on my bike to work.
western stinging nettle, Urtica dioica ssp. holosericea, White Mountains, elevation 2210 m (7245 ft). Note the tiny hypodermic needles, source of that burn familiar to many a bushwhacker.
Uploaded from my Flickr site: https://www.flickr.com/photos/127605180@N04/
Little caterpillar with dark band on its back found feeding on blackberry leaf
I finally think I can distinguish the two invasive Cotoneaster species common around the bay area. The one with the small leaf is C. pannosa and the big leaf is C. franchetii
http://envs.ucsc.edu/plants/Species%20pages/COTOPA.html