| Parthenium confertum | |
|---|---|
 | |
| Gray's feverfew flowering heads | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Asterales |
| Family: | Asteraceae |
| Tribe: | Heliantheae |
| Genus: | Parthenium |
| Species: | P. confertum |
| Binomial name | |
| Parthenium confertum | |
| Synonyms [1] | |
| |
Parthenium confertum, or Gray's feverfew, is a biennial plant belonging to the family Asteraceae. [2]
As can be confirmed on a page displaying images of different Parthenium species—the "feverfews"—documented by citizen scientists throughout the world, [3] Gray's feverfew is typical of the 16 or so feverfew species by producing a certain kind of flowering arrangement with these traits: [4]
Among features distinguishing Gray's feverfew from similar species of Parthenium are these: [2]
Unlike some other Parthenium species whose injured parts produce white latex historically used as a natural source for rubber, Parthenium confertum produces no white latex. [5]
In the Southwestern United States Parthenium confertum occurs in the states of Arizona, New Mexico and Texas. [2] In eastern Mexico it reaches as far south as the state of Querétaro in the country's central highlands. [6] In western Mexico it occurs in the states of Baja California, Sonora and Sinaloa. [1]
In the US state of New Mexico Gray's feverfew inhabits dry, sandy, rocky soils of mesas, canyons, hillsides, prairies, pinyon-juniper woodlands, scrub, grasslands and disturbed areas such as roadsides, at elevations of ~1200 – 2100 meters (3580–7000 feet). [7] Pictures on this page show an individual occupying a patch of prairie in an open forest on a slope of the Edwards Plateau at an elevation of ~1750m (~5750 feet). [8]
Four varieties of Parthenium confertum are accepted: [1]
Through natural hybridization in northeastern Mexico, Parthenium confertum along with Parthenium bipinnatifidum are reported to have produced the famously invasive and toxic weed Parthenium hysterophorus . [9]
Parthenium confertum, with a chromosome count of 35, is a polyploid. [10]
The genus name Parthenium probably either derives from the Greek parthenos, which means "virgin," or parthenion, the ancient name of some kind of plant. The allusion is unclear. [11]
The species name confertum apparently is derived from the New Latin confertus, meaning "crowded/pressed together/thronging," [12] which is a good description of how the numerous disk florets are crowded into such a small space in the flowering heads.