It helped Captain Cook's sailors stay afloat in the 18th century but these days Cook's scurvy grass is fighting for its own life.
The sub-species of coastal cress was used by the English explorer to ward off the vitamin C deficiency, scurvy, but it's now considered a threatened species.
However the plant is being monitored and nurtured at a Christchurch Reserve, alongside another trial of a rare native butterfly.
Katy Gosset pays a visit and meets the volunteers who are helping to make a difference.
Charlesworth Reserve Photo: RNZ/Katy Gosset
Photo: Nga Taonga Sound and Vision
