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.
Only a few species are dealt in by growers. The plants are recognized by their grey-green, divided, fern-like leaves and trusses of irregular flowers. Both tuberous- and fibrous-rooted varieties grow almost in any soil, and look well massed. The kinds worth attention are: bullosa, 6 in., purple and white; capnoides, 1 ft., sulphur white; lutea, 6 in., yellow; thalictrifolia, nobilis, and Wilsoni, all yellow-flowered; and cheilanthifolia, a fine dwarf rock plant, with beautifully dissected leaves.