Tridax

Linnaeus

Sp. Pl.2: 900. 1753

,

Gen. Pl. ed.5, 382. 1754

Etymology: Etymology recondite perhaps alluding to 3-lobed leaf blades characteristic of original species
Treatment appears in FNA Volume 21. Treatment on page 179. Mentioned on page 176, 177.
Perennials [annuals], 10–40[–80+] cm. Stems procumbent to ascending. Leaves basal and/or cauline; opposite; petiolate [sessile]; blades deltate, lanceolate, lance-ovate, or ovate, often pinnately or palmately lobed, ultimate margins coarsely toothed to subentire, faces glabrate, hirsute, scabrellous, or strigillose. Heads radiate [discoid], borne singly [in ± cymiform arrays]. Involucres cylindric to hemispheric, 4–8 mm diam. Phyllaries persistent, 11–15+ in 2–3+ series (outer usually shorter, more herbaceous, the inner often scarious). Receptacles convex to conic, paleate (paleae ± persistent, lance-linear, scarious, weakly conduplicate, often apically toothed). Ray florets [0–]3–8[–13], pistillate, fertile; corollas pale yellow [white or purplish]. Disc florets [20–]40–80+, bisexual, fertile; corollas yellowish [whitish or purplish], tubes shorter than cylindric or funnelform throats, lobes 5, usually deltate [sometimes rays 0 and corollas of peripheral florets ± bilabiate]. Cypselae obconic to obpyramidal, 3-, 4-, or 5-angled, densely piloso-sericeous [glabrous, villous]; pappi [sometimes wanting in rays] persistent, of [10–]20[–40], plumose [ciliate], setiform scales. x = 10.

Distribution

Distribution values could not be resolved to valid regions

mostly tropical, mostly New World.

Discussion

Species ca. 26 (1 in the flora).

Lower Taxa

Facts about "Tridax"
AuthorJohn L. Strother +
AuthorityLinnaeus +
Distributionmostly tropical + and mostly New World. +
EtymologyEtymology recondite + and perhaps alluding to 3-lobed leaf blades characteristic of original species +
Illustration copyrightFlora of North America Association +
IllustratorYevonn Wilson-Ramsey +
Introducedtrue +
Publication titleSp. Pl. + and Gen. Pl. ed. +
Publication year1753 + and 1754 +
Referencepowell1965a +
Source xmlhttps://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/f50eec43f223ca0e34566be0b046453a0960e173/coarse grained fna xml/V19-20-21/V21 440.xml +
SynonymsCompositae +
Taxon familyAsteraceae +
Taxon nameTridax +
Taxon parentAsteraceae (tribe Heliantheae) subtribe Galinsoginae +
Taxon rankgenus +
VolumeVolume 21 +