Ageratum maritimum

Kunth in A. von Humboldt et al.

in A. von Humboldt et al., Nov. Gen. Sp. 4(fol.): 117. 1818


4(qto.) 150. 1820

Common names: Cape Sable whiteweed
Synonyms: Ageratum littorale A. Gray Ageratum littorale var. hondurense B. L. Robinson
Treatment appears in FNA Volume 21. Treatment on page 482. Mentioned on page 481.
Annuals or perennials, 10–50 cm (semisucculent, rhizomatous, forming colonies). Stems decumbent to straggling or creeping (rooting at nodes), glabrous but for puberulous-pilose nodes. Leaf blades deltate-ovate to oblong, mostly 0.8–4 × 0.5–3 cm, (fleshy) margins toothed, faces glabrous or glabrate. Peduncles glabrous or glabrate. Involucres ca. 3 × 3–4 mm. Phyllaries elliptic-lanceolate, glabrous or glabrate, tips abruptly tapered to nearly obtuse. Corollas lavender or blue to white. Cypselae glabrous; pappi usually blunt coronas ca. 0.1 mm, rarely of separate scales.

Phenology: Flowering year round.
Habitat: Beach sand and nearby thickets, coral soils, salt marshes, hammocks, roadsides
Elevation: 0–10 m



Fla., Mexico (Quintana Roo), West Indies (Cuba, Hispaniola), Central America (Belize).


Plants from Florida (Ageratum littorale, the type from Florida) are described here. Plants of the West Indies and Mexico (broadening the species concept to A. maritimum, the type from Cuba) have various elaborations of vestiture and a more conspicuous pappus–coronas with even to laciniate margins or rings of nearly separate scales mostly 0.2–1.5 mm. In addition to the distinctive relatively small, glabrous or glabrate leaves, plants of A. maritimum are characterized by heads in clusters, usually held well beyond the leaves.

Selected References


Lower Taxa


Facts about "Ageratum maritimum"
AuthorGuy L. Nesom +
AuthorityKunth in A. von Humboldt et al. +
Common nameCape Sable whiteweed +
DistributionFla. +, Mexico (Quintana Roo) +, West Indies (Cuba +, Hispaniola) + and Central America (Belize). +
Elevation0–10 m +
HabitatBeach sand and nearby thickets, coral soils, salt marshes, hammocks, roadsides +
Illustration copyrightFlora of North America Association +
IllustratorLinny Heagy +
PhenologyFlowering year round. +
Publication titlein A. von Humboldt et al., Nov. Gen. Sp. +
Publication year1818 + and 1820 +
ReferenceNone +
Source xml grained fna xml/V19-20-21/V21 1210.xml +
SynonymsAgeratum littorale + and Ageratum littorale var. hondurense +
Taxon familyAsteraceae +
Taxon nameAgeratum maritimum +
Taxon parentAgeratum +
Taxon rankspecies +
VolumeVolume 21 +