Matricaria matricarioides (Less.) Porter - Pineapple Weed
Family - Asteraceae
Stems - Multiple from base, from taproot, ascending to erect, glabrous or with a few sparse hairs, to +15cm tall, herbaceous.
Leaves - Alternate, sessile to very short petiolate below, to +1.5cm long, +7mm broad, deeply pinnatifid to bipinnatifid. Ultimate divisions linear, lanate (sparse), green.
Inflorescence - Loose cymose arrangement of terminal flower heads. Heads globose to ovoid, to 8mm in diameter, with +100 flowers (florets).
Involucre - To 5mm tall. Phyllaries in two series, scarious-margined.
Ray flowers - Absent.
Disk flowers - Green, 4-lobed, 1.1mm long, glabrous. Achenes to 1.1mm long, tan in flower, terete, ribbed. Pappus a minute crown or absent. Receptacle conic.
Flowering - May - October.
Habitat - Rocky open ground, pastures, waste ground, disturbed sites, roadsides, railroads.
Origin - Native to Western North America and Eurasia, introduced in many parts of the U.S.
Other info. - This is a tiny plant but interesting none the less. The green subglobose flower heads are eye-catching. The plant is often not seen because of its small size. I must admit, I nearly stepped on it the first time I saw it.
Photographs taken at Taberville Prairie, MO., 6-7-03.