Marshmallow, Althaea officinalis, which has pale, downy leaves and pale pink flowers (now rare); (in later use also) any of various other mallows with pale flowers.
Origin
Late Middle English.
Definition of white mallow in US English:
white mallow
noun
Marshmallow, Althaea officinalis, which has pale, downy leaves and pale pink flowers (now rare); (in later use also) any of various other mallows with pale flowers.