V. odorata has scented flowers and a crown, with runners later in the year.
V. sororia has a rhizome and unscented flowers; it is deciduous.
V. riviniana forms branches, mainly later in the year, and unscented flowers.
There are other characters, but see if that's enough in your case.

The local weed is Viola riviniana. It is sometimes sold as V. adunca, a really quite different native species. It is also sold in its purpleleaf, bluish flowered form 'Purpurea', often as V. labradorica.

sororia has hairy stems. look closely at the stems and if you see tiny hairs then you could be looking at sororia. my sororia has white flowers with blue veins....