It is sometimes difficult to know whether the indoor plants that are so pleasing to your eye will be harmful to your cat. We have inherited many house plants from friends, sometimes not even knowing their names. Even plants purchased at garden centers can bear one of the many common names for that plant. Searches on the internet for harmful house plants are often fruitless, since they often only include a name and sometimes only one of the many names of a particular plant. We have found the following website greatly helpful in determining which of our house plants can stay and which need to go. It has pictures of many of the plants allowing us to identify even our plants that had no name and they are continuing to add more pictures. It also includes outdoor plants.
List of toxic plants: http://www.aspca.org/pet-care/poison-control/plants/