About Helenium puberulum DC.
Helenium puberulum DC., commonly called rosilla, is a North American flowering plant species belonging to the daisy family. It is native to California and Baja California, where it grows in moist habitats including riverbanks and meadows. Populations have also been found in Oregon, though these may be naturalized rather than native. Helenium puberulum is an annual or perennial herb; it can grow up to 160 centimeters tall, though many individuals are much smaller. Most of its leaves grow on the lower portion of the plant. Its stems are winged, with flaps of tissue running along their sides. A single plant can produce up to 30 flower heads arranged in a branched cluster. The flower head of this species is unusual: the area holding the disc florets is almost completely spherical, unlike the conical shape seen in most other species of the Helenium genus. A single head can sometimes contain over 1000 small disc florets. Each disc floret is yellow at its base and brown or purple toward its tip. This species produces 13 to 17 small, inconspicuous yellow ray florets that point backward down the flower stalk, and in some cases, ray florets are completely absent. Its fruit is a hairy achene that measures one to two millimeters long.
