Mallow
Malva sylvestris (Common Mallow, Blue Mallow), Malva moschata (Musk Mallow),
Family:
Malvaceae
Where to find this herb:
Roadsides, disturbed areas. Also as a garden escape. There are many pretty garden-varieties.
Part(s) used:
root, leaves, flowers
Special constituents:
malvin, plant slime
Correspondance:
13 (Cunningham), 14 (Culpeper), 16 (Crowley)
Uses:
Love magic. Medicinally: demulcent, pectoral
Kaasjeskruid 
Katost The name Malva comes from greek "malakhe" meaning "to soften", and probably refers to the medicinal use of the plant. All the different Mallow species has been used medicinally, but some are more efficient than others. In earlier times Mallow was an universal antidote against all kinds of problems, from blisters and insect bites to consumption. Now it is only used for its demulcent and pectoral properties against asthma and bronchitis.
As to its magic properties, Cunningham describes it as a protective plant, and one that can bring back a lost love. Grieve writes that the plant has been used to decorate graves. Mallow is not much used in modern witchcraft, which is a shame, because it clearly has potential. As to correspondances, I would say Venus; where Crowley got the Taurus-correspondance from I have no idea! He claims it's traditional, but I find it nowhere else. The flowers, the musk-like smell, and the demulcent properties clearly point to Venus.
The Mallows are closely related to the Marshmallow (Althaea officinalis)