There is a new line of feats, one of them Grasping Strike, that you qualify for either by being able to cast druid or ranger spells or by having the nature magic feat.
Am I right that the hunter, who can cast druid and ranger spells would still need nature magic because when he casts them they are hunter spells not druid and/or ranger spells?
I think you are right. Because, as you say, even though it draws on Druid and Ranger spells, the Hunter actually creates it's own spell list. It calls out in the examples that, for instance, reduce animal is a 2nd level hunter spell.
FWIW I'd amend the feat to allow casting hunter spells to qualify.