Ageratum L.

Ghazanfar, S. A., Edmondson, J. R. & Hind, D. J. N. (Eds). (2019). Flora of Iraq, Volume 6: Compositae.Kew Publishing

Morphology General Habit

Annual to perennial herbs or subshrubs, few- to many- branched, base often decumbent with numerous adventitious roots

Morphology Stem

Stems terete, striate, sparsely puberulous to sparsely hirsute

Morphology Leaves

Leaves opposite or sometimes alternate, short- to long-petiolate, lamina elliptical or lanceolate to deltoid or ovate, margins entire to dentate, apex not or scarcely acuminate, lower surface usually with large sessile or partially sunken glandular-punctate, usually 3-veined from or near base

Morphology Reproductive morphology Inflorescences

Inflorescence cymose to subcymose, sometimes subumbellate, pedicels short to moderately long

Morphology Reproductive morphology Inflorescences Capitulum

Capitula homogamous and discoid; phyllaries 30–40, distant, 2–3-seriate, equal or subequal, lanceolate, markedly indurate and often with scarious lateral margins; receptacle conical, glabrous or paleaceous

Morphology Reproductive morphology Flowers Florets

Florets 20–125; corollas white, blue, or lavender, funnelform or with distinct basal tube, lobes triangular, about as long as wide, papillose on inner surface, partially papillose and sometimes hispidulous on outer surface anther collar cylindrical; anther appendage large, somewhat longer than wide; style base not enlarged, glabrous; style arms linear, usually strongly and densely papillose

Morphology Reproductive morphology Fruits

Achenes prismatic, 4–5-ribbed, glabrous or ribs setuliferous; carpopodium distinct, usually large and asymmetrical; pappus lacking, or coroniform, or of 5 or 6 free, flattened, sometimes awn- like scales.

Distribution

Native of C America. Several species are now cultivated as garden plants in Europe, N Africa and SW Asia. A genus of some 40 tropical species, all but one American; the exception is A. conyzoides L.,

George R. Proctor (2012). Flora of the Cayman Isands (Second Edition). Royal Botanic Gardens, Kew

Morphology General Habit

Annual or perennial herbs, or sometimes shrubs; leaves opposite or sometimes a few upper ones alternate

Morphology Reproductive morphology Flowers

Heads discoid, many-flowered, in corymbs or panicles; phyllaries in 2–3 series, narrow and equal or nearly so; receptacle naked or scaly

Morphology Reproductive morphology Flowers Florets

Florets 5-lobed

Morphology Reproductive morphology Flowers Androecium Stamens Anthers

Anthers obtuse at the base and with a terminal appendage

Morphology Reproductive morphology Flowers Gynoecium Style

Style-arms elongate, exserted, terete

Morphology Reproductive morphology Fruits

Achenes 5-angled and ribbed; pappus of 5 or more scales, these awned or not, free or united at the base, rarely reduced to a cup.

Distribution

A mostly tropical American genus of about 35 species.

Compositae, H. Beentje, C. Jeffrey & D.J.N. Hind. Flora of Tropical East Africa. 2005

Morphology Reproductive morphology Flowers Androecium Stamens Anthers

Anthers short with ovate apical appendages.

Morphology Reproductive morphology Flowers Gynoecium Style

Style-arms clavate, papillate

Morphology Reproductive morphology Fruits

Achenes black, oblong, 5-ribbed, with short setae on the ribs; carpopodium large, white, asymmetrical; pappus of ± 5 awned scales, or reduced, awnless and occasionally absent.

Morphology General Habit

Annuals or short-lived sub-shrubby perennials

Morphology Leaves

Leaves opposite or sub-opposite apically, glandular-punctate beneath

Morphology Reproductive morphology Inflorescences

Inflorescence of loose to dense terminal corymbs

Morphology Reproductive morphology Inflorescences Bracts Involucre

Involucre campanulate; phyllaries bi-seriate, equal; receptacle broadly conical, epaleate

Morphology Reproductive morphology Flowers Corolla

Corollas tubular to funnel-shaped, tube externally glandular-stipitate, 5-lobed.