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 genus of North American annuals and perennials, vigorous in growth and glowing in colour, the flowers being remarkable for the raised cone-like disk in the centre. They flourish in any good garden soil, and may be raised from seeds and by division of the roots in autumn or spring.
Fig. 241- Rudbeckia hirta.
The best perennial kinds are californica, 5-6 ft., with large oval leaves and golden-yellow flowers 5 in. across; columnaris, 2-3 ft., with divided leaves and orange-yellow florets; hirta (fig. 241), 1-2 ft, yellow; laciniata, 2-15 ft., leaves deeply divided, flowers clear yellow, 3-4 in. across. There is a double-flowered variety, called "Golden Glow", which is particularly handsome; maxima, 4-8 ft, has large ovate blue-green leaves, and bright-yellow flowers 3-4 in. across; purpurea is now known under its old name of Echinacea (see p. 38); speciosa or Newmanni, 2-3 ft., popularly called "Black-eyed Susan", is very free flowering, the rich orange blossoms having a dark centre; subtomentosa, 3-4 ft, is a somewhat downy plant with fine starry yellow flowers scented like new-mown hay; nitida is a rather rare plant, very free in producing its rich-yellow flowers.