About Melampodium gracile Less.
Melampodium is a genus of flowering plants in the sunflower family. These rugged plants are native to tropical to subtropical regions, including Central America, the Southwestern United States, California, Florida, the Caribbean, and South America. Most species of the genus are found in Mexico, five species grow in the Southwestern United States, and three are scattered across Colombia and Brazil. There are two competing explanations for the origin of the genus name Melampodium. Some sources state the name derives from the Greek words μέλας (melas), meaning "black", and πόδιον (podion), meaning "foot", which refers to the dark color of the base of the stem and roots; members of the genus are commonly called blackfoots for this reason. Other authorities argue this derivation is incorrect, and instead maintain the name comes from Melampus, a well-known soothsayer in Greek mythology. Members of this genus include annuals, perennials, and bushy plants that grow up to 1 meter tall. When fully grown, these plants tend to fall over. They grow well in average, well-drained soil, but can also grow successfully on rocky desert soil. They are moderately to highly tolerant of drought and heat. Three species in the so-called white-rayed complex are xerophytic. The foliage of Melampodium plants ranges in color from bright green to grey-green. The opposite leaves are narrow, and measure 2 to 5 centimeters long. Terminal flower heads are about 2.5 centimeters wide. The genus produces a continuous display of daisylike ray florets, which are white only in the three white-rayed complex species, or can be cream or yellow. These ray florets surround a darker orange center that holds the disc florets. Eight to 10 broad disc florets are functionally staminate. The five outer bracts are partially joined along approximately half their length. The genus produces numerous seed-like fruits; each fruit consists of an inner involucral bract that encloses and is fused with an individual ray achene, with a few narrow scales at the tip. This makes Melampodium one of the most prolific genera of summer annuals, with new seedlings sprouting constantly. The genus has a wide range of haploid chromosome numbers, based on four basic chromosome numbers: x = 9, 10, 11, and 12. Several cultivars of Melampodium leucanthum have been developed, including 'Million Gold' and 'Showstar', most often to produce plants with a more compact growth habit. In horticultural trade, Melampodium has incorrectly been labelled Sanvitalia speciosa, which is an invalid name.
