This plant is coming up in my perennial garden. It has smooth stems that emerge from low growing leaves that are round, smooth-edged. There appears to be small white flowers about to bloom at the tips of the stems.
If it looks like the plant in these photos, it's probably Wood Bittercress - Cardamine Flexuosa. I have it in my garden, the flowers are quite small.
Count the stamens when flowers open as it could be Cardamine hirsuta, you might need a good macro to do that. Note that in C. fluxuosa 2 outer stamens can be small and not easily seen.
if this is what I have in my yard, you have to wear glasses when you pull it because it has tiny seeds that pop out and go everywhere when you pull it, or if you have small children or pets that walk in it.
Name: Leslieray Hurlburt Sacramento California (Zone 9b)
The seeds are super sticky when wet. Walked through bunches hidden in tall mixed grass/weed field and it was damp from dew and I could here the pods spraying seed onto everything including my damp cuffs. Sticky sticky sticky!
Hamilton Square Garden, Historic City Cemetery, Sacramento California.