''Cyclachaena xanthiifolia'' (

syn. The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linnae ...

''Iva xanthiifolia''), known as giant sumpweed, or rag sumpweed is a North American plant species in the sunflower family, Asteraceae. It is the only species in the genus ''Cyclachaena''. Giant sumpweed is believed to be native to the

Great Plains The Great Plains (french: Grandes Plaines), sometimes simply "the Plains", is a broad expanse of flatland in North America. It is located west of the Mississippi River and east of the Rocky Mountains, much of it covered in prairie, steppe, an ...

but is now found across much of southern Canada and the contiguous United States, though rarely in the

Southeast The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in navigation and cartography. A compass rose is primarily composed of four cardinal directions—north, east, south, and west—each sepa ...

. It is an annual herb roughly tall with stout, erect, branched stems. The stems are erect or ascending, finely ridged or grooved, and grayish-green. They are usually unbranched but sometimes have straight, upright branches. They are hairless near the base and are sparsely to moderately covered with fine curved or curled hairs above the base. In Britain and Ireland, it is known as marsh-elder. It has been introduced and semi-naturalized in central and southern Britain, partly via seeds bought for

bird food Bird food or bird seed is food (often varieties of seeds, nuts, and/or dried fruits) intended for consumption by wild and domestic birds. While most bird food is fed to commercial fowl (such as chicken or turkey), bird food is also used to fee ...

Description

The leaf pattern of this herbaceous plant is opposite, sometimes becoming alternate towards the top of the plant. The leaves are long-stalked and double-toothed with rough hairs on the top, and light green and fuzzy on the bottom. Lower leaves are long-stalked, the stalks up to long or longer. Upper leaves are short-stalked, and the stalks are up to long or longer. The flowers are green to white in panicled spikes roughly long. Some flowers are pistillate and fertile while others are perfect but sterile. The flowers bloom from August–October. The individual flower heads droop at the end of a long or longer stalk. The whorl of bracts at the base of the flower head (involucre) is long. The disk is composed of 8 to 20, usually no more than 10, male (staminate) florets in the center and usually 5 female (pistillate) florets around the margin. The flowers bloom from August–October. The staminate florets have stamens with the filaments fused into a tube and the anthers free but closely arranged in a ring. The corolla is about long and white to pale yellow. The pistillate florets have stamens with the filaments into a tube and the anthers free but closely arranged in a ring. The corolla is sometimes absent. When present it is about long and whitish. The fruit is an egg-shaped achene, dark brown to nearly black, long, with a tuft of hairs attached to one end.

Habitat and ecology

''Cyclachaena xanthiifolia'' grows in moist areas or previously disturbed sites. It can also be found in fields or along roadsides and streams.

Effects

If consumed by cows, it can make the milk that is produced taste bitter. The leaves can cause dermatitis in some individuals. The pollen of this plant can cause autumn hay fever in some individuals.

References

External links

* {{Taxonbar, from1=Q4505597, from2=Q5198107, from3=Q15598362 Heliantheae Flora of Northern America Monotypic Asteraceae genera