Invasive Weeds - Globe chamomile
Oncosiphon piluliferum (L. f.) Klersj
This plant is a close relative of Pentzia incana, another introduction from South Africa. It is an annual plant, which has escaped cultivation in the U.S. and also in western Australia. In 2005 it began to be observed at several different places in Arizona, possibly naturalized from plantings. To date, it has been documented growing in abundance along 5 miles of I-17 north of Phoenix, spreading up to ¾ mile into the desert on both sides of the interstate (Fenner 2005b, Northam 2005). Isolated patches of globe chamomile have also recently been identified near Skunk Tank Ridge south of Cave Creek on the Cave Creek Ranger District, at the Cave Creek Ranger Station, at the Sonora Desert National Monument, at Pinal City near Superior, along Highway 84 west of Casa Grande, at the Extension Service demonstration garden on east Broadway in Phoenix, on a disturbed site four miles east of I-17 on Carefree Highway.