This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Perennial or annual herbs. Leaves entire or dissected. Flowers large and showy, on long peduncles, nodding when in bud. Sepals 2. Petals 4. Stamens numerous. Capsule 1-celled, oblong, opening by short valves. There are nine species, of which one is European, two are North American, and the remainder Himalayan. The name is from a Poppy, and resemblance.
1. M. Cambrica. - The only European species, which is also found in some parts of western England and Wales. It is a perennial with bipinnatifid nearly glabrous leaves and pale yellow flowers on long peduncles.
There are several tall handsome species from the mountains of Northern India, three of which have been introduced, but they are very rarely seen. They have pinnatifid hispid leaves and large racemes of flowers from 2 to 3 inches in diameter, M. Wallichii has them pale blue; M. Nepalensis rich yellow, and M. aculeata rich lilac purple.