Another common name for this plant is Common Ironweed. However, in southern Illinois, this species is not common. Smooth Ironweed is one of the smaller Ironweeds with a compact inflorescence and smooth hairless leaves. Other Ironweed species have hairy stems or leaves. An exception is Vernonia gigantea (Tall Ironweed), which has hairless leaves and stems upon occasion. However, Tall Ironweed has a spreading inflorescence, and it is usually a taller plant (as the name implies). The larger leaves of Tall Ironweed exceed ½' across, while the leaves of Smooth Ironweed are ½' or less. Some authorities state that Smooth Ironweed has black dots on the undersides of the leaves, but this is not always true. The species in this genus are occasionally difficult to identify because they can hybridize with each other.

This native perennial plant is 2-4' tall and unbranched. The central stem is round, hairless, and white, light green, or reddish purple. The alternate leaves are up to 5' long and ½' across. They are narrowly lanceolate, narrowly ovate, or linear. Their margins are serrated, while the upper and lower leaf surfaces are hairless. The lower leaf surface also has a prominent central vein, and black dots may be present. The leaves are sessile against the stem, or they have short petioles. The central stem terminates in a flat-topped cluster of magenta compound flowers (i.e., a corymb). This flower cluster is quite dense, rather than loose and spreading. The flowering stalks may be slightly pubescent.  A compound flower consists of 15-30 disk florets with a short cylinder of green bracts underneath. These bracts are appressed together like fish scales, and they are often slightly ciliate. The cylinder of bracts spans about 1/5' across. A disk floret is magenta, with 5 spreading lobes and a prominent divided style. The blooming period occurs from late summer to early fall, and lasts about a month. There is no noticeable floral scent. The flowers are replaced by achenes that have a pappus of hair-like scales. These achenes can be blown several feet from the mother plant by gusts of wind. The root system is spreading and fibrous.

Vernonia fasciculata subsp. corymbosa (Schwein.) S.B. Jones:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Vernonia fasciculata subsp. fasciculata :
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Vernonia fasciculata var. fasciculata :
Canada (North America)
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Vernonia fasciculata var. corymbosa (Schwein.) B.G. Schub.:
Canada (North America)
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Vernonia fasciculata subsp. corymbosa (Schwein.) Á. Löve & D. Löve:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Vernonia fasciculata Michx.:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

United States

Origin: Unknown/Undetermined

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Unknown/Undetermined

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Tallgrass prairies of the midwestern and eastern states of the U.S.

Plants 3–12+ dm. Stems puberulent, glabrescent. Leaves mostly cauline; blades ± lanceolate, 5–12(–20+) cm × 5–18(–40+) mm, l/w = 5–9(–14+), abaxially glabrate (pitted, with awl-shaped hairs in pits), adaxially scabrellous, resin-gland-dotted (sometimes pitted). Heads in congested, corymbiform arrays. Peduncles 1–8(–12+) mm. Involucres ± campanulate, 5–7(–8+) × 4–6 mm. Phyllaries 25–35+ in 4–5+ series, glabrescent, margins arachno-ciliolate, the outer lance-ovate, 1–3 mm, inner oblong to linear-oblong, 5–7+ mm, tips acute or rounded-apiculate. Florets 12–25+. Cypselae 3.5–4 mm; pappi fuscous to purplish, outer subulate scales or bristles 20–30, 0.5–3+ mm, intergrading with 35–45+, 5–7+ mm inner subulate scales or bristles. 2n = 34.

Vernonia fasciculata subsp. corymbosa (Schweinitz) S. B. Jones; V. fasciculata var. corymbosa (Schweinitz) B. G. Schubert

This is the only member of its genus known in Montana. It is distinguished from other purple flowered, discoid composites (Brickellia, Eupatorium, Liatris) by having a pappus consisting of two series, one of capillary bristles and one of scales. It is distinguished from Vernonia fasciculata SSP FASCICULATA by its smaller leaves and overall size, wider involucre bracts, and scabrous (rough to touch) upper leaf surfaces.

Comments: Tallgrass prairie.

The flowers attract long-tongued bees, butterflies, and skippers primarily. Other visitors include bee flies and Halictid bees. These insects seek nectar, although bees also collect pollen. Among the long-tongued bees, are such visitors as bumblebees, Epeoline cuckoo bees, Miner bees, and large Leaf-Cutting bees. An oligolectic bee of Ironweeds is Melissodes vernoniae. The caterpillars of several moths feed on Ironweed, including Grammia parthenice (Parthenice Tiger Moth) and Perigea xanthioides (Red Groundling). Caterpillars that bore into the roots or stems of Ironweed include Papaipema cerussata (Ironweed Borer Moth), Carmenta bassiformis (Eupatorium Borer Moth), and some Polygrammodes spp. (Pyralid Moths). The bitter foliage of Ironweed deters consumption by mamamalian herbivores – it is known as an 'increaser' because it is one of the last plants to be eaten in overgrazed pastures. Photographic Location

Vernonia fasciculata (Smooth Ironweed)
(Also called Common Ironweed; bees collect pollen or suck nectar, other insects suck nectar; most observations are from Robertson, otherwise they are from LaBerge, Moure & Hurd, and Reed as indicated below)

Bees (long-tongued)
Apidae (Apinae): Apis mellifera sn; Apidae (Bombini): Bombus auricomus sn, Bombus bimaculatus (Re), Bombus griseocallis sn, Bombus pensylvanica sn fq, Bombus vagans (Re), Psithyrus variabilis sn fq; Anthophoridae (Ceratinini): Ceratina sp. (Re), Ceratina dupla dupla sn cp; Anthophoridae (Epeolini): Triepeolus sp. sn (Re), Triepeolus concavus sn fq, Triepeolus nevadensis sn fq, Triepeolus remigatus sn; Anthophoridae (Emphorini): Ptilothrix bombiformis sn; Anthophoridae (Eucerini): Melissodes agilis sn, Melissodes bimaculata bimaculata sn, Melissodes comptoides (LB), Melissodes denticulata sn cp fq olg, Melissodes nivea sn fq, Melissodes trinodis (Re), Melissodes vernoniae sn cp fq olg, Svastra atripes atripes sn, Svastra obliqua obliqua sn cp fq; Megachilidae (Megachilini): Megachile inimica sayi sn, Megachile latimanus sn cp; Megachilidae (Trypetini): Heriades leavitti sn cp

Bees (short-tongued)
Halictidae (Halictinae): Agapostemon sericea sn, Agapostemon virescens sn, Augochlorella striata (MH), Halictus ligatus cp, Lasioglossum sp. (Re), Lasioglossum imitatus (Re), Lasioglossum pilosus pilosus sn cp, Lasioglossum pruinosus sn cp, Lasioglossum versatus cp

Flies
Bombyliidae: Exoprosopa fasciata fq sn, Phthiria sp. (Re), Systoechus vulgaris sn, Systropus macer sn

Butterflies
Nymphalidae: Danaus plexippus, Speyeria cybele; Lycaenidae: Strymon melinus; Pieridae: Colias philodice, Phoebis sennae, Pieris rapae; Papilionidae: Papilio cresphontes, Papilio glaucus, Papilio polyxenes asterias, Papilio troilus

Skippers
Hesperiidae: Epargyreus clarus, Euphyes vestris, Polites origenes, Polites peckius, Polites themistocles

Moths
Noctuidae: Faronta diffusa

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

United States

Rounded National Status Rank: NNR - Unranked

Rounded Global Status Rank: TNR - Not Yet Ranked

Canada

Rounded National Status Rank: N1 - Critically Imperiled

United States

Rounded National Status Rank: NNR - Unranked

Rounded Global Status Rank: T4 - Apparently Secure

Canada

Rounded National Status Rank: N1 - Critically Imperiled

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

The preference is full sun, moist conditions, and fertile soil. Partial sun and slightly moister or drier conditions are also tolerated. This plant can withstand occasional flooding for short periods of time. The foliage is not bothered by pests and disease to any significant extent. Range & Habitat