Coriaria pottsiana

Coriaria pottsiana, commonly called the Hikurangi tutu or Pott's tutu, is a rare low-growing sub-alpine perennial summer-green shrub, only known to exist on a small grassy scree slope behind the tramping hut on Mount Hikurangi in the Gisborne Region of New Zealand's North Island. The Mt Hikurangi tramping hut is found at -37.90611°N, 178.05861°W.

Description
The delicate shrub grows to a height of 50 cm, with a 1 m spread. It is rhizomatous, with slender four-sided 40 cm stems growing from its slender rhizomes. Branches and branchlets are very slender, with small crinkled oblong to broad oval-shaped dark red opposite leaves with wavy margins that sometimes end in a distinct rounded point, are 5 - 9 * in size, are truncate at their base, are distant, have purplish undersides, and have slender petioles hardly 0.5 mm ($1/50$ in) in length. Its racemes are 4 - 14 cm long, and are found at the tip of stems, or elsewhere on main branches. Its white flowers, found on slender pedicels up to 7 mm in length, are distant, with broadly oval sepals about 1.5 mm in size (sometimes toothed), similar petals, and 5 ribbed carpels.

Like all Coriaria species, the plant is poisonous, especially the seed inside the small black berries. However, the juice of some Coriaria berries is not poisonous, and was used by Māori, who called members of the genus "tutu".