Parthenium

Linnaeus

Sp. Pl. 2: 988. 1753.

,

Gen. Pl. ed. 5, 426. 1754.

Common names: Feverfew
Etymology: Greek parthenos, virgin, or parthenion, ancient name of a plant allusion unclear
Treatment appears in FNA Volume 21. Treatment on page 20. Mentioned on page 8, 9.
 TaxonIllustrator 
FNA21 P02 Ambrosia artemisifolia.jpegAmbrosia artemisiifolia
Xanthium strumarium
Parthenium integrifolium
Barbara Alongi
Yevonn Wilson-Ramsey
Linda Ann Vorobik
FNA21 P03 Parthenium hysterophor.jpegParthenium hysterophorus
Parthenice mollis
Dicoria canescens
Linda Ann Vorobik
Linda Ann Vorobik
Marjorie C. Leggitt

Annuals, biennials, perennials, subshrubs, or shrubs [treelets], 1–120 [–400] cm. Stems ± erect, usually branched. Leaves usually cauline, sometimes in rosettes; alternate; petiolate or sessile; blades elliptic, lanceolate, linear, lyrate, oblanceolate, obovate, ovate, rounded-deltate, spatulate, sometimes (1–) 2-pinnately lobed, ultimate margins entire or toothed, faces usually hairy and glanddotted (at least the abaxial). Heads usually radiate, sometimes ± disciform (P. alpinum), usually borne in corymbiform or paniculiform arrays (in glomerules in P. argentatum, borne singly in P. alpinum and P. ligulatum). Involucres ± hemispheric [rotate], 3–8 (–12+) mm diam. Phyllaries falling, 10 (–16) in 2 series, usually distinct (partially connate in P. alpinum), outer 5 (–8) herbaceous to scarious, inner 5–8 ± scarious to membranous. Receptacles flat to conic; paleae cuneate to flabelliform, scarious or membranous, distally papillate and/or fimbrillate, all or the peripheral each ± enfolding a disc-floret. Ray (pistillate) florets 5 (–8), fertile; corollas ochroleucous, tubes stout, glandular, laminae oblong to reniform or orbiculate, or ± coroniform (none in P. alpinum). Disc-florets 12–60+, functionally staminate; corollas ochroleucous, funnelform, lobes 5 (filaments distinct, anthers connate). Cypselae (black) oblanceoloid, obovoid, or pyriform, often ± obcompressed (shed together with subtending phyllary and 2 contiguous disc-florets and their investing paleae); pappi 0 (shoulders of cypselae may bear 1–3 pappuslike, triangular to ovate, or ± subulate enations). x = 9.

Distribution

New World, mostly warm-temperate and tropical, some temperate, in Old World

Discussion

Species ca. 16 (7 in the flora).

Key

1 Plants 1–2 cm (plants cespitose or forming mats); heads borne singly > 2
1 Plants (5–)15–120 cm (plants not cespitose or forming mats); heads in glomerules, or in simple or compound, corymbiform or paniculiform arrays > 3
2 Corollas of pistillate florets bearing laminae 1–2 mm Parthenium ligulatum
2 Corollas of pistillate florets lacking laminae Parthenium alpinum
3 Shrubs > 4
3 Annuals, biennials, or perennials > 5
4 Leaf blades oval-elliptic to obovate (sometimes pinnately 3–7-lobed or round-toothed, ultimate margins entire) Parthenium incanum
4 Leaf blades lanceolate to oblanceolate (margins mostly entire, some with 1–5 sharp teeth) Parthenium argentatum
5 Perennials; leaf blades usually crenate to serrate, sometimes coarsely toothed or somewhat lobed (then mostly toward bases); pappus-like enations from shoulders of cypselae 0 or 2(–4), erect to spreading, ± subulate or threadlike Parthenium integrifolium
5 Annuals or biennials (sometimes persisting); leaf blades mostly 1–2-pinnately lobed; pappus-like enations from shoulders of cypselae 2, erect, ± deltate to ovate. > 6
6 Biennials (sometimes flowering first year or persisting); leaf blades ± pinnately lobed, abaxial faces strigillose (usually with erect hairs 1–2 mm as well) Parthenium confertum
6 Annuals (rarely persisting); leaf blades (1–)2-pinnately lobed, abaxial faces scabrellous (seldom with erect hairs 1–2 mm) Parthenium hysterophorus
... more about "Parthenium"
not tailed +, rounded +  and obtuse +
connate +  and distinct +
subequal +
scarious +
usually ovate +  and lanceolate +
usually deltate +  and lanceolate +
paniculiform +  and corymbiform +
indeterminate +  and determinate +
John L. Strother +
Linnaeus +
decurrent +
compound +  and simple +
lobed;spatulate;rounded-deltate;ovate;obovate;oblanceolate;lyrate;lanceolate +
winged;ribbed;winged;ribbed +
tuberculate +  and rugose +
barbellulate +  and barbellate +
Feverfew +
ochroleucous +
villous +, strigillose +, hispidulous +, glabrous +  and warty +
scabrellous +  and tuberculate +
obcompressed +, pyriform +, obovoid +  and oblanceoloid +
fertile +  and bisexual +
New World +, mostly warm-temperate and tropical +, some temperate +  and in Old World +
Greek parthenos, virgin, or parthenion, ancient name of a plant +  and allusion unclear +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
in corymbiform , glomerate , paniculiform , racemiform or spiciform , arrays +  and singly +
indeterminate +
homogamous +  and heterogamous +
each +  and sessile +
less scarious +  and membranous +
0.3 cm3 mm <br />0.003 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
hemispheric +
conspicuous +
oblong +  and reniform or orbiculate or more or less coroniform +
sessile +  and petiolate +
deltate +
dentate to pinnatifid or palmatifid +  and entire +
herbaceous +  and scarious +
2-carpellate +
peripheral +
papillate +
fimbrillate;cuneate;flabelliform +
membranous +  and scarious +
persistent +
unequal +  and subequal +
Sp. Pl. +  and Gen. Pl. ed. +
1753 +  and 1754 +
bearing subulate enations +, hairy +  and bristly +
mears1975a +  and rollins1950a +
exalbuminous +
appendaged +  and truncate +
hirsutulous +  and glabrous +
papillate +
Undefined (tribe Undefined) subtribe Ambrosieae +  and Undefined (tribe Undefined) subtribe Iveae +
Parthenium +
Asteraceae (tribe Heliantheae) subtribe Ambrosiinae +
campanulate +  and cylindric +
toothed +  and entire +
perennial +, biennial +  and annual +
shrub +  and subshrub +