The inflorescences of Sunflower Family (Asteraceae) members are called heads. Heads are complex and consist of many flowers situated on a receptacle and surrounded by involucral bracts called phyllaries. Each individual flower on the head may be surrounded by papery bracts called chaff scales (collectively chaff).
There are four types of Asteraceae heads: radiate, ligulate, discoid and disciform. I discussed these head types in my 23 January 2017 post entitled “Asteraceae”. In that post I illustrated three of the head types, but did not have a photograph of a disciform flower. Now I do.
Disciform flower heads seem to have all disk flowers but the outer flowers are differentiated morphologically and functionally from the inner disk flowers. Q tips (Micropus californicus) are an example of disciform heads.
Q tips are native annuals found in California and Oregon. Their habitat is seasonally moist soils, particularly vernal pool communities, clearings and disturbed areas below 5,000 feet.
Q tips are erect plants with slender stems. Although the stems are commonly unbranched, some do branch once or twice. The alternate leaves are entire and linear. Small clusters of heads occur terminally on the stems. The outer flowers in a Q tips head are pistillate. These outer flowers are enclosed with thick, wooley chaff scales that resemble the head of a Q tip. The style protrudes from these pistillate flowers. The inner flowers are bisexual and tubular and do not have chaff.
Other common names for M californicus are cottonweed, slender cottonweed, micropus, and cotton top. A synonym is Bombycilaena californicus. The genus name comes from the Greek: “micros” meaning small and “pous” meaning foot. The species name refers to California.
These Q tips were photographed at the Clear Creek Picnic Area at Whiskeytown National Recreation Area in Shasta County CA in May. Unfortunately, since these photographs were taken the Carr Wildfire devastated this area.