Ageratum Conyzoides L.

• Scientific Name: Ageratum Conyzoides L.
• English Name: Tropic Ageratum

Ascending to erect, branching, annual herb with strong odor. Stem cylindric, hairy, much branched with enlarged nodes. Leaves simple, opposite, ovate with crenate or serrated margins, with acute tip narrowing at the base to a hairy petiole. Inflorescence is terminal corymb with clusters of several flower heads. Flower heads made up of tubular flowers above the rows of bracts, forming an involucre. Fruit is black achene, ribbed or angled with a pappus of white, pointed, reduced awns.

Grows among a wide range of cultivated crops. Also found in wastelands and on roadsides.

Propagation by seeds. Plants flower throughout the year. One plant can produce as many as 40,000 seeds, half of which germinate shortly after they are shed. Seeds spread mainly by wind and water and germinate under a wide range of conditions.

Usually a weed in plantation crops and pastures, it also occurs in short-term crops. It is a serious weed of corn, peanut, upland rice, and sugarcane. Sometimes cultured as an ornamental. An alternate host of Cassytha filiformis L., a parasitic flowering plant; two fungi, Cercospora agerati Steven and Puccinia conoelinii Seym.; and several nematode species.