Plains Yarrow. Woolly Milfoil (Achillea lanulosa) grows in moist places on the plains from Texas to Canada, Mexico, and California. It is very much like the woods yarrow but differs in that it has fewer gray-green leaves and round-topped flower clusters. Its blooming season is a little later than that of the woods yarrow, which blooms in April and May.
TEXAS SQUAW-WEED
Texas Squaw-Weed. Clasping-Leaved Groundsel (Senecio ampullaceus) is an annual plant which grows so abundantly on the sandy prairies of Texas that it forms a carpet of gold for miles and miles. It is one of the earliest spring flowers to bloom in such showy profusion. The plants commonly grow 1½-2 feet high, being branched above and forming flat-topped flower-clusters which are often a foot broad. When quite young, the plants are densely white-woolly but become smooth and shining with age. The irregularly toothed leaves are 3-6 inches long and have a broad clasping base. The groundsel belongs to one of our largest groups of plants, some 1200 species being widely distributed over the earth.
Fine-leaved or woolly groundsel (Senecio filifolius) has woolly leaves divided into narrow segments. The large heads are often in bloom throughout the year in West Texas and New Mexico.
AMERICAN STAR THISTLE
American Star Thistle. Basket Flower (Centaurea americana) is often called spineless thistle because the leaves do not bear spines as do the leaves of its close relative, the purple thistle. It is also known as powder puffs, sweet sultan, and “cardo del valle.” It is a hardy annual which is widely cultivated. Basket flower is the name under which it is known in cultivation—a name which refers to the stiff, straw-colored bracts of the flower head. These bracts are not spiny but are divided at the tip into finger-like projections.
Before the flowers are fully opened, the heads resemble a shaving-brush, and this is a common name frequently applied to this and other thistles. All the flowers are tubular and divided into five long narrow lobes. In one variety the fully-opened flower cluster has an outer border of numerous lavender flowers with cream-colored flowers in the center. There is another variety which has outer flowers a deep rose or reddish purple and center flowers pale pink or rose; sometimes there is little difference in shade between the inner and outer flowers.
The stems are usually branched and grow about two feet high. They are marked with wing-like ridges and are covered with the overlapping, ascending leaves. In Texas the flowers begin to bloom in May and continue into June, being at their best the first week in June. After the flowering season, the foliage becomes yellow and dried, and the old stalks remain conspicuous in the fields for several months. The star thistle is found on plains from Missouri to Louisiana, Mexico, and Arizona. The variety which has reddish-purple flowers is very abundant in the vicinity of Waco and Fort Worth.