Several large flower-heads terminate the branches; they measure from 2 to 4 inches across. The central disc is, at first, hemispherical and green but finally becomes elongated and brownish. The rays number six to twelve and are bright yellow in color. This species blooms from July until September and is found from Me. to Manitoba and southward.
Ten-petalled Sunflower (Helianthus decapetalous). This is a slender-stemmed, graceful, showy-flowered Sunflower, common in damp woods and on the borders of thickets, from Me., Quebec, and Minn. southward. The branching stem grows from 2 to 5 feet tall; it is slightly hairy-rough on the upper portions but smooth below. The leaves are thin, rather rough-broad lance-shaped, short-stemmed and grow oppositely on the stem; they are all sharply saw-toothed. The showy flowers, growing on slender peduncles from the ends of the branches, are 2 to 3 inches across. Though often with ten rays, they just as frequently have any number from 8 to 15.
Common Sunflower (Helianthus annuus) is the common garden Sunflower that often has such enormous heads. The normal, wild plant is common from Minn. to Texas and westward. The flower-heads range from 3 to 6 inches in diameter; it is only the cultivated variety, produced from this, that has the mammoth heads we often see.
In its wild state the plant grows from 3 to 6 feet tall. Their period of bloom is from July until September.
Jerusalem Artichoke (Helianthus tuberosus) is, like the [Common Sunflower], a valuable species, and one that is often cultivated because of its edible roots, these being tender and of good flavor; they are eaten raw or cooked. Their value as articles of food was first discovered by Indians and by them imparted to our early colonists. The name Jerusalem, in connection with this plant, is a corruption from the name applied to the species by Italians (Girasole Articocco), meaning sunflower artichoke.
It is a handsome plant, the stout, leafy, hairy stalk growing from 3 to 12 feet tall and being topped with several large showy flowers. The large, three-veined leaves are hairy and have toothed margins. They are chiefly set oppositely on the stem, although some of the upper ones may alternate. The several flower-heads are large, measuring up to 3 inches across. The central florets are greenish yellow and are surrounded by from 12 to 24 lone, golden-yellow rays.
This species is often also known as the Canada Potato and the Earth Apple. Its range extends from southern Canada southward nearly to the Gulf.
