Kingdom: Plantae
(Unranked): Angiosperms
(Unranked): Rosids
Order: Rosales
Family: Rosaceae
Subfamily: Rosoideae
Tribe: Sanguisorbeae
Subtribe: Sanguisorbinae
Genus: Acaena
Species: A. caesiiglauca
Scientific name: Acaena caesiiglauca
Common names: Glaucous Piripiri, Glaucous Bidibid

Acaena caesiiglauca is a native evergreen perennial ground cover found in mountainous areas and subalpine tussock grasslands, east of the Southern Alps, South Island, New Zealand. 
It forms large patches meters across. The blue-grey leaves comprise 7–9 leaflets and are 3.5–5 cm long. It does not have underground runners.
In summer whitish flowers on stalks develop then globes of spiny bracts form into brownish-red burrs, like pom-poms above the leaves. It is these burrs that trampers often find adhering to their socks and are carried away, an attribute that makes this plant loathed by sheep farmers.
Sold by a ground cover.

Photographed at Otari Native Botanic Garden and Wilton's Bush Reserve. Wellington.  Acaena caesiiglauca Glaucous Bidibid.JPG

Acaena caesiglauca Glaucous Piripiri-007.JPG
Acaena caesiiglauca Glaucous Bidibid -002.JPG 

A whitish flower developing. March New Plymouth.
Acaena caesiglauca Glaucous Piripiri-005.JPG 

Whitish flowers on a stalk (March, New Plymouth)
Acaena caesiglauca Glaucous Piripiri-006.JPG 

Thanks to Wikipedia for text and information: