Docks are all in the genus Rumex and have varying properties and effectiveness as medicinal plants. They’re related to Sorrel (Rumex acetosa) and share the same sharp bite of flavour due to its levels of Oxalic acid. Docks aren’t especially high in any particular nutrients.
Docks all share a love of damp or wet places and the general way to tell them apart is by their fruit shapes which vary remarkably from species to species. There is some general variation in leaf shapes, but it’s not a great indicator.
The most common variety of Dock around Gawler is Clustered Dock (Rumex conglomeratus).
Docks are full of tannins, making them excellent for treating minor wounds, they are also the traditional remedy for Nettle stings, being quite acidic (the sting of a Nettle is alkaline). Docks contain chemicals called anthraquinones which are quite powerful laxatives, so take care not to eat too much!