Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Fabales
Family: Fabaceae
Subfamily: Mimosoideae
Genus: Acacia
Species: A. paradoxa
Binomial name: Acacia paradoxa
Synonyms: Acacia armata, Acacia armatoides, Racosperma paradoxum, Acacia barteriana, Acacia bartheriana, Acacia furcifera, Acacia hybrida, Acacia microcantha, Acacia ornithophora, Acacia tristis, Acacia undulata
Common names: Kangaroo acacia, Kangaroo thorn, Prickly wattle, Hedge wattle, Paradox acacia, Prickly Acacia, Prickly Moses, Prickly Shrub Wattle, Acacia Hedge

Acacia paradoxa is is an evergreen, intricate, spiny shrub in the Fabaceae (pea) family from southern and eastern Australia. 
It is an environmental weed in New Zealand where it can be found growing in waste places, scrubland, and forest margins forming tall thickets. Since it is nitrogen fixing it alters the regrowth of low-fertility native plant communities such as ferns, some native trees and plants. Acacia paradoxais produces many seeds and these are spread by water and soil movement.

Acacia paradoxais is a large, nitrogen-fixing shrub grows up to 3 metres tall often with drooping outer branches. The alternate, sparsely hairy leaves are crinkly. The new leaves are covered in hairs. The leaves are actually flattened leaf stems (phyllodes) and they have two long, thin, stiff spines at their bases. These 4-15 mm long spines deter livestock from feeding on the plant.
During July–November bright globular golden flower heads develop. There are one(or rarely 2) per axil. The flowers are hermaphrodite (have both male and female organs). The brown seed pods are 2-7 cm long and 3-5 mm wide, straight to slightly curved and shortly hairy. The shiny seeds are green to dark brown, elliptical, 3-5 mm long x 2 mm wide.

1-Acacia pycnantha .jpg

1-Acacia paradoxa.JPG

The globular golden flower heads.
1-Acacia armata C.jpg

The two long, thin, stiff spines at the base of the phyllodes
1-Acacia paradoxa leaves in summer.jpg

Thanks to Wikipedia for text and information: