What are the legal rights of a widow whose husband didn't have a will?
All community property and joint tenancy property goes to the surviving spouse. Separate property is divided between you and the deceased spouse's children.
Joint tenancy property goes to the surviving joint tenant, which may or may not be you. It is possible to change the nature of joint tenancy property so that at least part becomes community property. You can get more information by reading a Nolo Press book on Estates and Trusts.
Thanks for clarifying, George! I should have said "property held in joint tenancy by the spouses."