Field Hedge Parsley. A European invader. According to the Ca. Invasive Plant Council this species has a moderately serious effect on native ecosystems.
Until I saw the seeds, I assumed it was a small poison hemlock, but the seeds are wrong for that. The seeds are sticky.
Blooms March-July on most trails in the front and back country. It can grow up to 1m high. There is a congener, T. nodosa which is shorter and bushier and is also supposed to be in our area. I’m not sure I can distinguish the two yet.
Seen blooming and with seeds on 1 June on Jesusita trail halfway up from the water treatment plant. It’s about a meter high, with few white flowers and few leaves, some of the leaves are turning purple.
Note that the petals outermost on an umbril have bigger petals than the inner petals
Formerly we were supposed to have subspecies purpurea here, but CalFlora no longer lists any subspecies for this species. The leaves still are purple though.