Nabalus altissimus (L.) Hook.

Tall White Lettuce

Nabalus_altissimus_plant.jpg
STATS

Native
CC = 5
CW = 3
MOC = 32

© SRTurner

Family - Asteraceae/Cichorieae

Stem - Erect, to 2 m, usually glabrous, often with purple coloration, sometimes glaucous.

Nabalus_altissimus_stem.jpg Stem.

© SRTurner

Leaves - Variable. Springtime emergent leaves often deeply lobed or with indistinct hastate lobes at bases. Lower cauline leaves petiolate, usually lobed, usually with a few broad, shallow teeth. Upper cauline leaves progressively smaller, with shorter petioles, less often lobed.

Nabalus_altissimus_leaf.jpg Emergent leaves.

© SRTurner

Nabalus_altissimus_leaf3.jpg Lower stem leaf.

© SRTurner

Nabalus_altissimus_leaf2.jpg Upper stem leaf.

© SRTurner

Inflorescence - Typically broad panicles, with heads tending to cluster. Heads nodding.

Nabalus_altissimus_inflorescence.jpg Inflorescence.

© SRTurner

Involucre - 9-14 mm long, cylindrical, with short outer bracts and 4-6 longer, pale greenish inner bracts.

Nabalus_altissimus_involucre.jpg Involucre.

© SRTurner

Flower - Ligulate florets 4-6, cream to yellow, with 5-6 mm orange-brown pappus.

Nabalus_altissimus_flower.jpg Flower.

© SRTurner

Fruit - 4-5 mm long, light brown or yellowish brown.

Flowering - July - October.

Habitat - Streambanks, mesic and bottomland forests, bluffs.

Origin - Native to North America.

Other info - This is the species of Nabalus most often encountered in Missouri. It is easily recognized by its open inflorescences and narrow heads with smooth involucres. It is most commonly found in moist areas with light to moderate shade. It seems to be a favorite of deer, which will often browse it preferentially over other vegetation.
The species was formerly known as Prenanthes altissima.

Photographs taken at Taum Sauk State Park, Iron County, MO, 9-27-2010, Young Conservation Area, Jefferson County, MO, 9-24-2014, Valley View Glade Natural Area, Jefferson County, MO, 9-28-2014, and Glassberg Conservation Area, Jefferson County, MO, 9-25-2015 (SRTurner).