Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
Order: Ranunculales
Family: Ranunculaceae
Genus: Ranunculus
Species: R. lyalii
Binomial name: Ranunculus lyallii
Common names: Mount Cook lily, Mountain buttercup, Mount Cook buttercup, Giant buttercup

Ranunculus lyallii is a native species of Ranunculus, endemic to New Zealand, where it occurs in the sub-alpine to alpine herbfields of the South Island and Stewart Island. It is found at altitudes of 700–1,500 m. It is not a lily, it is the world’s largest buttercup.

Ranunculus lyallii is a herbaceous perennial plant growing to 60–100 cm tall, with a stout rhizome. The leaves are glossy dark green, peltate and have been recorded as big as 40cm across. The leaves have stomates on both sides. They have the ability to close or open these stomates depending on the conditions to stop them drying out.
The flowers are 5–8 cm diameter, with 10–20 white petals and numerous yellow stamens; flowering is from late spring to early summer.

Ranunculus lyallii is under threat by grazing animals such as introduced deer, chamois and Himalayan tahr. It is also susceptible to damage from walkers and trampers when wandering off formed tracks.

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The round cup-shaped leaves. Rainwater collects in the hollows and is drunk by trampers.
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Thanks to Wikipedia for text and information https://creativecommons.org/licenses/by-sa/3.0/