Snap Cress Weed

Just south of the vegetable garden there is a patch of these weedy crucifers that we don’t believe were here last year. This morning when we stepped through the patch the seed pods were going snap-snap-snap and tiny seeds were flying everywhere. I keyed the plant out in the Jepson Manual today and think it is hairy bittercress, Cardamine hirsuta. This would be interesting because the Jepson treatment of this introduced annual says it’s known to occur in the Klamath Region but not in points south. Hence this occurrence could be a range extension. The reference I’d really like to check is the new Weeds of California and Other Western States. There are many copies of this in the campus bookstore but it is shrinkwrapped in two volumes and I wasn’t peeking.