Cirsium altissimum (L.) Spreng.
Family - Asteraceae
Stems - To +3m tall, branching, herbaceous, erect, striate, pubescent.
Leaves - Alternate, typically glabrous above, densely pubescent to lanate below, mostly entire with spined margins, sometimes lobed, to +30cm long, +10cm wide, sessile or short-petiolate, typically lanceolate, oblong, or elliptic, reduced towards apex.
Abaxial surface of leaf.
Inflorescence - Single flower heads terminating stems.
Involucre - To 3.5cm tall, +3cm wide, subglobose to vase-shaped. Phyllaries imbricate, appressed, spine (bristle) tipped, typically with a lighter midrib.
Involucre with the subtending bracts.
Involucre with the subtending bracts removed.
Ray flowers - Absent.
Disc flowers - Corolla pink to rose, to +30mm long, tubular, 5-lobed. Style well exserted. Achenes to 6mm long, 2mm wide. Pappus of numerous plumose bristles.
Flowering - July - October.
Habitat - Dry woodlands, slopes, thickets, disturbed sites, waste ground, roadsides, railroads.
Origin - Native to U.S.
Other info. - This is the
tallest of the plants in this genus in Missouri (altissimum means "the tallest"). It is very common throughout the state except for the extreme southeastern corner. It is a common roadside plant in the Ozarks.
Photographs taken in the Ozark Scenic Riverways, Shannon County, MO., 8-9-03.