Eclipta prostrata (L.) L.
Yerba de Tajo
Family - Asteraceae
Stems - To +/-50cm tall, single from base but with many spreading branches, from fibrous roots, strigose, herbaceous, subsucculent, erect or ascending, often rooting at lowest nodes, terete, purplish in strong sun.
Leaves - Opposite, sessile, lanceolate , shallow serrate, to 13cm long, 3cm broad, strigose, acuminate.
Inflorescence - Axillary and terminal clusters of 1-3 flower heads. Peduncles to -2cm long, densely antrorse strigose.
Involucre - Typically a single series of 8-10 unequal phyllaries. Phyllaries to 7mm ong, 2.3mm broad, antrorse strigose externally, glabrous internally, green, acute.
Ray flowers - Fertile, pistillate. Ligules to -2mm long, .5mm broad, notched or rounded at apex. Achenes 3-angled, white, 1mm long, glabrous. Pappus absent.
Disk flowers - Disk 4-10mm broad. Corolla tube to .9mm long, 4-lobed, glabrous, white. Lobes acute, .3mm long. Stamens 4. Anthers purple, .5-.6mm long, included, connate around style. Style whitish at apex (stigmas). Achenes (in fruit) to 2.5mm long, warty, 4-angled. Pappus absent to a minute crown. Receptacle flat. Chaff to -3mm long, translucent yellow, antrorsely barbellate.
Flowering - July - October.
Habitat - Wet areas.
Origin - Native to U.S. and tropical areas worldwide.
Other info. - This plant
is quite prolific. It can grow on land or directly in the water. The stems
often form roots from the nodes when floating in the water. The tiny white
flowers and opposite leaves are good characteristics for identifying this
species in the field. It is common throughout Missouri.
Photographs taken at the Kansas City Zoo, 7-2-99 and off of Lee Rd 51, Lee County, AL., 10-7-04 (DETenaglia); also Dresser Island Conservation Area, 8-13-2012 (SRTurner)