The accepted name for all beet cultivars, like chard,
sugar beet and
beetroot, is
Beta vulgaris subsp.
vulgaris
https://en.wikipedia.org/wiki/Chard
Yes, the chard IS a beet green, it does not make the same sort of root as a table beet or sugar beet does.
Patihum, have made those type pickles with longer stems left whole on the skinnier ones like Bright Lights. Split the fordhooks into 2 or 3 length wise pieces.