T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Rubus squarrosus (Leafless lawyer)

Kingdom: Plantae
(Unranked): Angiosperms
(Unranked): Eudicots
Order: Rosales
Family: Rosaceae
Subfamily: Rosoideae
Tribe: Rubeae
Genus: Rubus
Species: R. squarrosus
Binominal name: Rubus squarrosus
Common names: Leafless lawyer, yellow-prickled lawyer

Rubus squarrosus is a native vine which can reach a height of 3m and with a similar spread. It is an intriguing leafless vine with conspicuous bright yellow thorns along its stems creating a skeletal look.
Rubus squarrosus is perhaps the most remarkable of the genus Rubus, as, in open situations and on shrubs, the leaflet blades remain undeveloped and the leaves consist of rather elongated petioles and the almost threadlike midribs of the leaflets, all beset with yellow prickles. Such leaves are very effective in clinging to any support. When the stems reach into tree crowns there is a trend towards normal leaves with well-formed narrow leaflets. 
It is endemic to North and South Islands, from Ahipara south but is rare north of the Manawatu.

A thorny tangled mass.

Undeveloped leaflet blades with yellow prickles on the stems which stand out prominently because of the paucity of leaves. 

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/