This is a genus of North American plants, some of them valuable for the border; all are hardy, and easily propagated by dividing the roots.
Rudbeckia fulgida has large, brilliant yellow flowers, with a dark centre, or disk; about two feet high; continuing in bloom all the months of July and August.
R. purpurea. - Purple Rudbeckia. - This plant grows from three to four feet high. The disk of the flower is very rich, appearing, in the sun, of a golden crimson; the rays are purple, and, in some of the varieties, quite long.
R. nudiflora. - This is a beautiful species; it grows three feet high; the stems branched, producing a long succession of flowers, with long, conical, dark disks, and very long, wavy rays, of a pure, clear yellow.
There are many other species, but mostly coarse-growing plants.