Magnolia is the common name for a variety of plants, some of which are poisonous and some of which are not. For example, the Southern magnolia, a tree found throughout the southern United States, has poisonous seeds, but the star magnolia, another common plant, is completely non-toxic.
The Southern magnolia also goes by the scientific name Magnolia grandiflora, and is often called simply magnolia. Some other poisonous species are Magnolia acuminata, Magnolia biondii, and Magnolia denudata, all of which share the common name of magnolia with Magnolia grandiflora. All of these toxic species are trees. Star magnolia, which is non-toxic, is a bush rather than a tree, but caution should still be used around bush-like magnolias. Stunted toxic trees can be mistaken for bushes, especially as many magnolia species grow similar-looking leaves and flowers.