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.
Summer-flowering perennial herbs with the habit of Malva, differing from that genus in the structure of the carpels, which are provided with a short beak. Involucel of 1 to 3 free bracts, or wanting. These very handsome plants, about seven in number, are from North America. They are sometimes referred to malva, and formerly they bore the name Nuttallia. The name is of classical origin.
1. C. involuerata. - This is one of the species with an invo-lucel. It is of straggling habit, with cordate deeply-lobed leaves, lobes again divided into narrow acute segments. Flowers solitary, on long peduncles, purple with a light centre.
2. C. pedata. - An erect branching species, about a yard high, with pedate leaves. Flowers about 3 inches in diameter, purple, with a white spot at the base of each petal.
Other species are: C. cordifolia, with pink flowers; C. digitata, syn. Nuttdllia grandiflora, destitute of involucel and having fringed petals of a bright crimson purple; and G. Papa-ver, similar to the last, with a 3-leaved involucel, and rich claret-purple flowers on long peduncles.