Ixerba

Ixerba
Tawari, Bay of Plenty
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Crossosomatales
Family:	Strasburgeriaceae
Genus:	Ixerba
Species:	I. brexioides
Binomial name
Ixerba brexioides A.Cunn.

Ixerba brexioides, the sole species in the genus Ixerba, is a bushy tree with thick, narrow, serrated, dark green leaves and panicles of white flowers with a green hart. The fruit is a green capsule that splits open to reveal the black seeds partly covered with a fleshy scarlet aril against the white inside of the fruit. Ixerba is an endemic of the northern half of the North Island of New Zealand. Common names used in New Zealand are tāwari for the tree and whakou when in flower. It is assigned to the family Strasburgeriaceae.

Tāwari is a small tree of up to 10 m high with a spreading crown. The trunk is usually between 2-4 dm in diameter, and covered by a dark to grayish brown bark. Young branches have few flat-lying pale unicellular T-hairs, while the peduncles, pedicels, sepals and petals are thickly covered in such hairs, giving them a felty look. The leaves are alternately positioned along the stem and often almost create a whorl at the end of a growth period, with the bud at the end covered in stout triangular scales. These scales have entire margins fringed with simple single celled hairs. The first leaves to appear when growth recommences are an intermediate series between schales and full leaves. Stipules at the base of the leaf stem are absent. The leaf stalk is stout, fleshy and about 2 cm long. The somewhat fleshy and distinctly leathery simple leaf blades are yellowish to dark green on top and pale green beneath and measure 6-16 × 1–4 cm, are lanceolate to elliptic in shape, while the widest point may be at or beyond midlength, with a pointy tip, and the edges are coarsely serrated. A small gland is present at the tip of each tooth. Young leaves are often reddish and have rolled-in margins. Leaves on young shoots may be relatively narrower. Old leaves discolor to orange or red.

Flower buds are formed in March and April and these open from October to the end of December varying according to location and altitude. The inflorescence sits at the end of the branches in an umbel-like panicle that consists of five to ten flowers. Each flower is hermaphrodite, starsymmetric, 2½—3½ cm in diameter and produces copious amounts of nectar, but apparently does not emit a scent. The five sepals are broadly oval, covered in downy hairs and 5–6 mm long. The five petals are overlapping in the bud, white, felty, spoon-shaped with a narrow base (or claw). The claw is 1½-2 cm long and is inserted on a 5-lobed disc. The five stamens extend well beyond the corolla and alternate with the five lobes of the disc at the centre of the flower. The filaments are very long and white. The anthers are connected to the filaments midlength and open in lengthwise slits towards the middle of the flower. Pollen grains have five slits. The nectar is produced by the ledges of the disc, just above the petal inplant. The five styles that rise from the disc are sometimes free from each other at their based and are twisting and fused higher up.

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Wikipedia