The scientific name meaning “of the Centaurs” refers to the use by the Centaurs of certain species for healing. The cornflower or bachelor’s button (Centaurea cyanus) is a well-known garden annual.
WAVY-LEAVED THISTLE PURPLE-THISTLE
Wavy-Leaved Thistle (Carduus undulatus) is the common prairie thistle and is particularly abundant in the vicinity of Fort Worth. It grows only 1-2 feet high, and the upper leaf-surfaces are yellow-green. The heads are nearly twice as large as those of the purple thistle, and the flowers are a lovely lavender color. It ranges from Southern Canada to Texas and Arizona and blooms in Texas from April to June.
Purple Thistle (Carduus austrinus) is the common thistle in the south-central part of the state. It is a tall, much branched plant, 3-4 feet high, with long-stalked heads of purple flowers. The stems are white-woolly, and the leaves are white-felty beneath and dark-green above, wavy-margined, lobed or divided, the segments being tipped with spines. The heads are about 1½ inches high and broad. The numerous light purple flowers are all tubular with narrow lobes. The thistles belong to a large group, its most renowned representative being the Scotch thistle.
NODDING THISTLE
Nodding Thistle. Silver Puffs. Sunbonnet Babies (Thrysanthema nutans) lacks the spines of the true thistles, but other characters show that this interesting little plant is closely related to the thistle group. The leaves form a basal rosette from which grows the slender, leafless flowering stalk bearing the nodding flower head. The lyre-shaped leaves are wavy-margined, dark-green above and white-felty below, 2-4 inches long. The stalk is sometimes 15 inches long but is commonly about 8 inches high. The creamy-white flowers are rather inconspicuous, but as the seeds mature, the soft white bristles spread into a showy whorl. The plants are found in scattered places in rich soil from Central Texas to Mexico.
Closely kin to the nodding thistle is the desert holly (Perezia nana), which has salmon-pink flowers and holly-like leaves. It is a low plant seeking the shelter of creosote bush, yucca, and other shrubs in West Texas.