Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Asterales
Family: Asteraceae
Subfamily: Cichorioideae
Tribe: Cichorieae
Subtribe: Hyoseridinae
Genus: Sonchus
Species: S. grandifolius
Binominal name: Sonchus grandifolius
Synonyms: Embergeria grandifolia
Common name: Chatham Island sow thistle, Giant sow thistle, Embergeria, Puha aotea

Sonchus grandifolius is thistlelike herb endemic to the Chatham Islands. It has been threatened with extinction due to the grazing of animals but with pest control, it is rapidly recovering.
Sonchus grandifolius has fleshy, pale green leaves that have tooth lobes and they can be up to 1 m long. If parts of the plant are broken or cut it will exude a thick milky sap.
Pale creamy-yellow flowers with splashes of violet develop December to February on erect flower heads. 
The plant's rootstock is creeping, deep rooting, stout rhizomes. These can be found 1 m down in sandy soils. The plant dies down over winter. 

For more photos and information visit: http://www.nzpcn.org.nz/flora_details.aspx?ID=62

1- giant sow thistle Sonchus grandifolius.JPG


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