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.
A small genus of annual and perennial plants with compound leaves very finely divided into thread-like segments. Flowers yellow or red. Sepals 5 to 8, petaloid, deciduous. Petals 5 to 16, destitute of glands. Carpels numerous, with 1 pendulous seed in each. The species are limited to the temperate zone of the northern hemisphere in the Old World. The name is of classic origin.
2. A. aestivalis. - An erect almost singled-stemmed annual, with flowers about half the size of the preceding, of a deep crimson, or more rarely orange, with a black spot at the base of the petals. Styles straight.
3. A. Pyrenaica. - Rather taller than No. 1, with distinct radical leaves on long stalks, and fewer petals. Flowers yellow. Summer.