Ixerba brexioides is an evergreen tree species in New Zealand, which alone forms the plant genus, the Ixerba within the family Strasburgeriaceae. In New Zealand, the kind of " Tawhiri " or " Tawari " is called, the flowers " whakou ".
It is an evergreen tree with protruding crown, which is up to ten meters high. The strain reached a diameter of 0.2 to 0.4 meters. The bark is dark green to gray - brown. The branches, leaves and inflorescences are slightly hairy when young.
The leaves are pseudoquirlförmig. You are nebenblattlos. The petioles are two inches long and fleshy. The leaves are yellow-green to dark green at the bottom always brighter at the top. Young leaves are often reddish. They are somewhat fleshy, very leathery, 60 to 160 millimeters long and 10 to 40 mm wide, lanceolate to elliptical with a pointed apex. The leaf margin is distinctly and coarsely toothed. At the top of each tooth sits a small gland.
The inflorescences are terminal, consisting of five to ten flowers that form an umbrella- shaped ear. The flowers are white, relatively large ( 25 to 35 mm diameter) each with five sepals and petals, ten stamens with thick connectives. The pollen is 4 - 5 colporat - up. The ovary is striking is composed of five carpels and gradually changes into the pen. The stylus is strongly furrowed and twisted spirally at the top. At the base of the ovary sits a lobed nectary. The vascular bundles in the base of the flower are crowded together tightly. Bloom time is October and November.
In the tapered capsule fruit are a few shiny black seeds with an eye-catching orange - red aril. Fruit ripening is from November to January. The distribution of seeds is done possibly by pigeons.
The kind of missing non-hydrolyzable tannins. The chromosome number is n = 25
Ixerba brexioides is endemic to the North Island of New Zealand. It is the only endemic family of New Zealand. The area is restricted to the north of the North Island about Waitomo, Paeroa and Te Urewera Range north to the hills south of Kaitaia.
The tree grows in kauri forests and montane cloud forests. He prefers shady and sheltered places, often near streams and on constantly moist soil. The species is rather rare and only occurs in some places up in larger numbers. But it is not at risk.
The species can be taken only with difficulty in culture. It is believed that it requires a mycorrhiza to grow. If it is planted along with Griselinia littoralis, they should grow well.
Within the Crossosomatales Ixerba is the sister taxon of Strasburgeria. Both groups have the following characteristics in common: at least in the flower cells with thickened congested inner tangential walls; needle-like crystals; spiral leaves with glandular - toothed edges; large flowers with calyx spiraligem; flat filaments; Anthers about three millimeters long; Carpels sessile, Epitrop with long hollow pen, the remains of the fruit; Chromosome base number of 25
Cronquist 1981 Ixerba had placed in the Grossulariaceae, Airy Shaw in the Brexiaceae and Tachtadschjan 1997 in the Rosidae - Brexiales. The Angiosperm Phylogeny Group, the genus since 2009 together with Strasburgeria in the Strasburgeriaceae family.