Ranunculus lyallii, Mount Cook lily, Mountain buttercup, Mount Cook buttercup, or Giant buttercup

It is a native species of Ranunculus, endemic to New Zealand, and it grows in sub-alpine to alpine herbfields in the South Island mountains from Marlborough to Stewart Island from 700m to 1500m asl. It is well adapted to grow in infertile soils and it favours stream banks and damp locations in scrub and grasslands. Due to its ornamental flowers, the Mount Cook buttercup has also been cultivated. Plenty of water, good drainage and shade in hot areas are required and it is intolerant of high nutrient levels in soil. It 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.

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