Plant Listings

Conyza canadensis

Common Names: Smooth Horseweed

Family: Asteraceae

Habit: Conyza canadensis is an herbaceous annual to 1.5 meters in height. The vegetative structures are glabrous or covered with hirsute pubescence. The sessile leaves are up to 10 cm long, linear to lanceolate, and ciliate along the entire (sometimes toothed) margin and an acute leaf apex.

The (zygomorphic and actinomorphic) flowers are arranged in panicles of heads. The heads contain numerous flowers and are subtended by an involucre composed of a series of linear phyllaries. The calyx is modified as hairs forming a pappus. There are both perfect (and actinomorphic) and imperfect (carpellate and zygomorphic) flowers in the heads. The perfect flowers are in the center of the head and imperfect around the edges of the heads.

The imperfect flowers have the corolla fused into a single structure that opens along its inner edge. There are no stamens. The ovary is inferior with a single locule and seed. The perfect flowers have 5 fused, white petals. There are 5 stamens. The ovary is inferior with a single locule and seed. The fruits are an achene at maturity that is covered with bristles.

Habitat: Conyza canadensis grows in human disturbed areas such as roadsides, abandoned fields and yards.

Distribution in Bahamas/Globally: Conyza canadensis occurs on all island groups within the Bahamian Archipelago as well as North America. It has become a weedy species across the globe.

Medicinal/Cultural Economic usage: Conyza canadensis has no known medicinal use in the Bahamas.

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