My in-laws just bought a house in Escondido, Ca, and there is a mass of this growing in a raised planter bed. Any ideas? I'm not familiar with the plants in their area, and they have no clue what it could be. It's growing in full sun. I didn't take a photo of an open pod, but it's mostly a foamy/pithy white inside with a few round seeds.
[quote="Metrosideros"]Maybe Mustard or other Brassica.
Can you show the whole plant?[/quote]
I think you're right about Brassica--I started searching images, and it appears to possibly be Radish Pods. The plant isn't in very good shape due to some winter frost. There really isn't much more to see other than what I photographed--I should have pulled back more, but I didn't and this is the only photo I have.