Family - Apiaceae

Stems - To +1m tall, from thick taproot, multiple from base, branching, herbaceous, erect, retrorse strigose, scabrous.

Leaves - Alternate, pinnately divided, petiolate. Petiole involute, scabrous, retrorse strigose, sheathing(on lower leaves). Lobes of lower leaves typically pinnatifid. Ultimate leaf divisions serrate(the teeth mucronate).

Inflorescence - Axillary and terminal compound umbels. Axillary umbels actually opposite the leaves. Peduncles to 10cm long, retrorse strigose. Rays 5-7, antrorse stigose, subtended by 1-3 bracts. Bracts linear, to 1.5cm long, antrorse strigose, typically unequal. Umbellets subtended by +/-8 bractlets. Bractlets to 5mm long, linear-lanceolate, antrorse strigose. Raylets +/-3mm long, antrorse strigose.

Flowers - Petals 5, white, unequal, free, antrorse strigose externally, glabrous internally, deeply cleft with an inflexed central appendage, the largest to 2mm long and broad. Stamens 5, alternating with petals, small. Styles 2, .5mm long, green, with expanded stylopodium. Stigma globose. Ovary inferior. Sepals 5, much reduced, alternating with petals, acute, to .4mm long. Fruit 8-ribbed, with uncinate bristles on ribs(to 2mm long), glandular and regular pubescent, to 5mm long, 3mm broad.

Flowers close-up.

Fruits...

...again.

Flowering - June - August.

Habitat - Waste ground, disturbed sites, thickets, roadsides, railroads.

Origin - Native to Eurasia.

Other info. - If you've ever had the unfortunate predicament of walking through a mass of these plants you realize why the plant has spread so rapidly in such a short time, being introduced for just about a century. The fruits grab hold of nearly any fabric and any hairy appendage which happens to be exposed. The task of removing the fruits is less than enjoyable.
Synonyms include T. arvensis (Huds.) Link and T. anthriscus (L.) Bernh. - Rydberg.

Photographs taken in Eminence, MO., 6-6-03, and in the Ozark Scenic Riverways, Shannon County, MO., 6-22-04.