This section is from the book "Commercial Gardening Vol2", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
A large genus of plants chiefly remarkable for their elegantly cut foliage and graceful appearance. Although many species varying from 6 in. to 4 ft. high are dealt in by hardy-plantsmen, very few are grown by marketmen. One of the most popular kinds is the Maidenhair Meadow Rue (T. minus or T. adiantifolium), which resembles a deep-green Maidenhair Fern in appearance, and is frequently mistaken for one. It makes a graceful pot plant, and being a native of Britain is quite hardy. The foliage is useful for cutting and mixing with other flowers. It may be increased from seeds or by division. Another useful species is T. Deldvayi, from China, 2-4 ft. high, having finely divided leaves and lilac-purple flowers with conspicuous bunches of yellow stamens.