Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

Home to the plants of the Sonoran, Chihuahuan and Mojave Deserts

Cirsium ochrocentrum, Yellowspine Thistle

Oncosiphon piluliferum, Stinknet

Stinknet is an introduced species in Arizona and the southwestern United States causing much alarm from environmental groups that recognize how quickly this species can destroy yards and natural areas. Oncosiphon piluliferum Stinknet, or Globe Chamomile as it is erroneously called has pretty rounded yellow flowers that unfortunately result in many folks wanting to bring it home as a garden species. You should resist any temptation to encourage this aggressive habitat destroying species. Oncosiphon piluliferum Oncosiphon piluliferum, Stinknet, Southwest Desert Flora Stinknet has pretty showy yellow or gold colored flowers. The showy flowers attract a lot of positive attention however this species is an aggressive weed and spreads quickly through and disrupting native plant communities. Oncosiphon piluliferum Stinknet leaves are bright green, alternate along the stems and pinnatifid with 3 to 5 linear lobes. Plants are bushy and often attractive in appearance. Oncosiphon piluliferum Oncosiphon piluliferum, Stinknet, Southwest Desert Flora

Scientific Name: Oncosiphon piluliferum
Common Name: Stinknet

Also called: Globe Chamomile

Family: Asteraceae, Sunflower Family

Synonyms: (Cotula pilulifera, Matricaria globifera, Matricaria discoidea, Pentzia globifera, Oncosiphon pilulifer)

Status: Introduced; native to South Africa

Duration: Annual

Size: Up to 2 feet (60 cm) or more

Growth Form: Forb/herb pungently, vile scented, resin from stem and leaf glands; multiple dark green stems; growth is upright or spreading; stems with short stiff bristles; solitary plants mostly rounded over.

Leaves: Green; dense leaves arranged alternately along stem; leaves deeply divided into linear segments; small stiff hairs; leaves also with strong vile or pungent odor; also emit resin from surface glands.

Flower Color: Yellow or Gold; showy flower heads solitary or in small clusters on branch tips; disk flowers only; flowers and flower parts with vile pungent odor; fruit is cypsela.

Flowering Season: February or March through June or July; largest populations dependent on rainfall

Elevation: Sea Level to 3,000 feet (900 m)

Habitat Preferences: Lower desert areas in clay, sandy and gravelly soils and washes, common in disturbed areas; coastal scrub, dunes and chaparral vegetation.

Recorded Range: Central Arizona and moving to the north and south. In California in the Los Angeles area with confirmed records south of San Diego. This species was first recorded as an invasive in California.

North America & US County Distribution Map for Oncosiphon piluliferum.

North America species range map for Oncosiphon piluliferum:

North America species range map for Oncosiphon piluliferum: Click image for full size map.
Click image for full size map

Invasive/Noxious Weed Information: Unknown
Threatened/Endangered Information: Unknown

U.S. Weed Information: In North America Oncosiphon piluliferum can be weedy or invasive according to the following authoritative sources:

  • Arizona Dept of Agriculture; Oncosiphon piluliferum; Noxious Weed, R3-4-245; Defined, in part as “Noxious weeds are of limited distribution”...“and may be a high priority pest”.
  • California Invasive Plant Council (Cal-IPC); Oncosiphon piluliferum; “There is a high risk of this plant becoming invasive in California#8221;

  • Wetland Indicator: In North America Oncosiphon piluliferum has the following wetland designations:
  • Arid West, FACU;
  • Western Mountains, Valleys, and Coast, FACU.

  • FACU = Facultative Upland, usually occur in non-wetlands, but may occur in wetlands

    Genus Information: In North America there are 2 introduced species and 2 accepted taxa overall for Oncosiphon. Worldwide, The Plant List includes 8 accepted species names for Oncosiphon.

    The genus Oncosiphon was published by Mari Källersjö in 1988.

    In the southwest United States Arizona and California have 1 species of Oncosiphon. Data approximate and subject to revision.

    Comments: Stinknet is an introduced species found in central Arizona and southeast California. It was brought to Phoenix as a cultured desert habitat specimen. It gets the name Stinknet from its strong foul odor. It is an exceptionally fast moving invasive in Arizona, moving quickly through the greater Phoenix area.

    Stinknet is so named because it has a strong unpleasant odor.

    Importance to Wildlife, Birds and Livestock
    Beneficial Value to Butterflies, Bees and Insects
    Oncosiphon piluliferum has inconspicuous flowers and small plants which may be visited by hummingbirds and/or small mammals including rodents in search of food.

    The genus Oncosiphon (Oncosi'phon:) is from the Greek "onkos" meaning "bulb and mass" and "siphon" meaning "tube"; referencing the tube of the corolla.

    The genus Oncosiphon was published by Mari Källersjö in 1988.

    The species epithet "piluliferum" (pilulif'erum:) means bearing little balls of globules, which here refers to the globular flowering heads.


    Date Profile Completed: 06/26/2012, updated 09/09/2020
    U.S. Dept. of Agriculture, Natural Resources Conservation Service on-line database and USGS ITIS search; accessed 09/09/2020.
    The Plant List (2013). Version 1.1. Published on the Internet;; accessed 09/09/2020.
    David J. Keil 2012, Oncosiphon pilulifer, in Jepson Flora Project (eds.) Jepson eFlora, /eflora/eflora_display.php?tid=103818, accessed on September 09, 2020.
    California Invasive Plant Council, Cal-IPC; accessed on March 19, 2020.
    David J. Keil , Flora of North America; Asteraceae, Oncosiphon 1. Oncosiphon piluliferum (Linnaeus f.) Källersjö, Bot. J. Linn. Soc. 96: 314. 1988. ; Flora of North America North of Mexico. 16+ vols. New York and Oxford.
    FNA 2006, Jepson 2012; Editors: L.Crumbacher 2012; from SEINet Field Guide, on-line; accessed 09/09/2020.
    Wikipedia contributors, 'Oncosiphon pilulifer', Wikipedia, The Free Encyclopedia, 14 May 2020, 00:23 UTC, [accessed 9 September 2020]
    Seiler, John, Peterson, John, North American species range map courtesy of Virginia Tech, Dept. of Forest Resources & Environmental Conservation
    SEINet synonyms, scientific names, geographic locations, general information.
    Etymology:Michael L. Charters California Plant Names: Latin and Greek Meanings and Derivations; A Dictionary of Botanical and Biographical Etymology - (accessed 02/03/2020)