What is the meaning of Marsh_mallow?

A European species of plant in the mallow family, Althaea officinalis, historically used medicinally and the source of what became the modern marshmallow confection (which no longer contains the plant).

Hibiscus moscheutos (crimsoneyed rosemallow, swamp rosemallow. eastern rosemallow)

Malva sylvestris (common mallow)

Source: wiktionary.org