T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Malva neglecta (Dwarf mallow)

Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Malvales
Family: Malvaceae
Genus: Malva
Species: M. neglecta
Binomial name: Malva neglecta
Synonyms: Malva rotundifolia
Common name:  Roundleaf mallow, Buttonweed, Cheeseplant, Cheeseweed, Dwarf mallow, Spare tyre.

Malva neglecta is an invasive, spreading annual, rarely biennial weed found in abandoned fields, vacant lots, areas along roads, railroads, edges of yards and disturbed waste ground where garden refuse is dumped. 
Malva neglecta usually has a prostrate growth habit forming sprawling patches > 1 m wide. Sometimes it grows nearly erect. It has a deep fleshy taproot. 
The flowers (> 2 cm across) are single or in clusters of 2 to 4 where leaf stalk meets the stem. They have 5 petals (>15 mm long) that are white or tinged with pink or purple, often with pale violet lines along their length. The calyx has 5 sepals with oval tips and is about half the length of the petals.
The round to kidney-shaped leaves alternates along the stem with long leafstalks, 3 to 5 times as long as leaves. They are deeply indented at the base and toothed around edges (5 to 9 shallow lobes). They have short hairs on top, bottom and on leafstalk.
The fruit capsules are composed of round, flattened lengthwise one-seeded cheese-shaped segments. Cheeseweed being one of its common names. These segments are rounded on the back, short-hairy but otherwise nearly smooth. These easily become detached from the plant after ripening.
Malva neglecta herb has been used in traditional medicine internally as a tea or externally as baths for treatment of disorders of the skin, gastrointestinal tract and respiratory tract.  

A spreading stem.

Flower with fruit capsules bottom right.

The underside of a leaf.

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/