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.
Erect graceful perennials. Leaves compound. Flowers small, numerous, in panicles or racemes. Sepals 4 or 5, petaloid. Petals absent. Stamens numerous, with long usually yellow conspicuous anthers projecting beyond the calyx. Carpels several, with one pendulous seed. A classical name of obscure derivation. Species numerous, widely spread.
1. Th.flavum. Meadow Rue. - About 3 feet high. Leaves dark green, much divided, with cuneate segments. A showy plant with bright yellow flowers. A British plant, flowering at Midsummer.
2. Th. minus. - The typical form of this species is a very elegant little plant, producing its graceful foliage in dense tufts. The flower-stem rises about a foot high, and the flowers are small and greenish white, sometimes tinged with red. Native of North Europe and Asia, including Britain.
3. Th. anemonoides, syn. Anemone thalictroides. - A pretty dwarf species, resembling an Anemone, but destitute of an involucre. In this species the petaloid sepals are more conspicuous than the stamens. The flowers are white, umbellate; stems about a foot high, with a whorl of leaves at the base of the umbel. There is a double variety. North America.
4. Th. aquilegifolium. - A handsome tall-growing species with much-divided glaucous leaves resembling those of the Columbine, and large stem-clasping stipules. There are two varieties of this, one with purplish stems and flowers. Germany.