About Romneya coulteri Harv.
Romneya coulteri, commonly known as Coulter's Matilija poppy or California tree poppy, is a perennial flowering plant in the poppy family Papaveraceae. It is native to southern California in the United States and Baja California in Mexico, where it grows in dry canyons within chaparral and coastal sage scrub plant communities, and sometimes grows in areas that have been recently burned. It is a popular ornamental plant cultivated for its large, showy flowers. Its specific epithet coulteri was chosen to commemorate Thomas Coulter, an Irish botanist and explorer. This herbaceous perennial can grow over 2 m (7 ft) in height, and its stems grow from a network of rhizomes. Its leaves are gray-green with a waxy texture, each divided into a few lance-shaped lobes, and leaf blades can reach up to 20 cm (7.9 in) long. The inflorescence is a large, solitary flower with three sepals and six crinkly white petals. Each petal is up to 10 cm (4 in) long and nearly as wide, giving the flower a total width of up to 20 cm (7.9 in), which is the largest of any California wildflower. A cluster of many yellow stamens sits at the center of the flower. The fruit is a bristly capsule 3–4 cm (1–2 in) long that holds many tiny seeds. Once planted, this species often grows aggressively. It spreads clonally through underground rhizomes, and new shoots can appear a meter or more away from the original plant. This plant produces the largest flowers of any species native to California, with only Hibiscus lasiocarpos producing blooms of comparable size. It was nominated for the title of California state flower in 1890, but the California poppy won the nomination by a large margin. When cultivated in the United Kingdom, both the species Romneya coulteri and its cultivar 'White Cloud' have received the Royal Horticultural Society's Award of Garden Merit.
