View source for Tithonia

{{Treatment/ID
|accepted_name=Tithonia
|accepted_authority=Desfontaines ex Jussieu
|publications={{Treatment/Publication
|title=Gen. Pl.,
|place=189. 1789
|year=1789
}}
|common_names=Sunflowerweed
|basionyms=
|synonyms=
|hierarchy=Asteraceae;Asteraceae tribe Heliantheae;Asteraceae (tribe Heliantheae) subtribe Helianthinae;Tithonia
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Asteraceae]]</div><div class="higher-taxon"><small>tribe</small>[[Asteraceae tribe Heliantheae]]</div><div class="higher-taxon"><small>subtribe</small>[[Asteraceae (tribe Heliantheae) subtribe Helianthinae]]</div><div class="higher-taxon"><small>genus</small>[[Tithonia]]</div></div>
|etymology=From Greek mythology, Tithonus, son of Laomedon and consort of Aurora, symbolic of old age; perhaps alluding to gray to white induments of some plants
|volume=Volume 21
|mention_page=page 135
|treatment_page=page 138
}}<!--

--><span class="statement" id="st-d0_s0" data-properties="whole-organism duration;whole-organism duration;whole_organism atypical some measurement;whole_organism some measurement;whole_organism growth form;whole_organism growth form"><b>Annuals,</b> perennials, subshrubs, or shrubs [trees], 70–500 [–700] cm.</span> <span class="statement" id="st-d0_s1" data-properties="stem orientation;stem architecture"><b>Stems </b>erect, branched.</span> <span class="statement" id="st-d0_s2" data-properties="leaf position"><b>Leaves </b>all or mostly cauline;</span> <span class="statement" id="st-d0_s3" data-properties="">opposite (proximal) or mostly alternate;</span> <span class="statement" id="st-d0_s4" data-properties="leaf arrangement;leaf arrangement;leaf architecture;leaf architecture">petiolate or sessile;</span> <span class="statement" id="st-d0_s5" data-properties="blade quantity;blade architecture;blade architecture;blade architecture;blade architecture;blade shape;blade shape;blade shape;blade shape;base shape;base shape;ultimate margin shape;face pubescence;face pubescence;face pubescence;face pubescence;face pubescence;face pubescence;face pubescence">blades often (1-), 3-nerved, or 5-nerved, mostly deltate or pentagonal [lanceolate, linear], sometimes 3-lobed or 5-lobed, bases ± truncate or auriculate [attenuate] (sometimes decurrent onto petioles), ultimate margins serrate to crenate, faces glabrate, ± hirsute, pilose, soft-pubescent, or villous, often glanddotted.</span> <span class="statement" id="st-d0_s6" data-properties="head arrangement"><b>Heads </b>borne singly (peduncles usually distally dilated, fistulose).</span> <span class="statement" id="st-d0_s7" data-properties="involucre shape;involucre diameter"><b>Involucres </b>campanulate to hemispheric, 10–20+ mm diam.</span> <span class="statement" id="st-d0_s8" data-properties="phyllary duration;phyllary quantity;series quantity"><b>Phyllaries </b>persistent, 12–28+ in 2–5 series (linear to broadly rounded, unequal to subequal, apices acute to rounded).</span> <span class="statement" id="st-d0_s9" data-properties="receptacle shape;receptacle architecture"><b>Receptacles </b>hemispheric to convex, paleate (paleae persistent, embracing cypselae, striate, ± 3-toothed, middle teeth larger, stiff, acute or acuminate to aristate).</span> <span class="statement" id="st-d0_s10" data-properties="ray-floret quantity;ray-floret architecture"><b>Ray-</b>florets 8–30, neuter;</span> <span class="statement" id="st-d0_s11" data-properties="corolla coloration;corolla coloration">corollas yellow or orange.</span> <span class="statement" id="st-d0_s12" data-properties="disc-floret atypical quantity;disc-floret quantity;disc-floret reproduction;disc-floret reproduction"><b>Disc-</b>florets 40–120 [–200+], bisexual, fertile;</span> <span class="statement" id="st-d0_s13" data-properties="corolla coloration;tube height or length or size;lobe quantity;lobe shape">corollas yellow, tubes shorter than throats (bases of throats bulbous and hairy), lobes 5, ± triangular (anthers black, brown, or tan, bases cordate-sagittate, appendages ovate; style-branches relatively slender, appendages penicillate or lanceolate to attenuate).</span> <span class="statement" id="st-d0_s14" data-properties="cypsela shape;cypsela shape;cypsela shape;cypsela shape;cypsela shape;cypsela shape"><b>Cypselae </b>(black or brown) ± compressed or flattened, often 3-angled or 4-angled or biconvex, ± cuneiform in silhouette (sometimes with basal elaiosomes);</span> <span class="statement" id="st-d0_s15" data-properties="">pappi 0, or ± coroniform (of ± connate scales, 1–2 scales sometimes subulate to aristate).</span> <span class="statement" id="st-d0_s16" data-properties="pappus presence;pappus shape;x chromosome quantity">x = 17.</span><!--

-->{{Treatment/Body
|distribution=sw United States;Mexico;Central America;in se United States;West Indies;South America;and Old World
|discussion=<p>Species 11 (3 in the flora).</p>
|tables=
|references={{Treatment/Reference
|id=la1982a
|text=La Duke, J. C. 1982. Revision of Tithonia. Rhodora 84: 453–522.
}}
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Perennials, subshrubs, or shrubs; phyllaries 16–28; ray laminae 48–69 mm; disc florets 80–120+; cypselae 4–6 mm
|[[Tithonia diversifolia|Tithonia diversifolia]]
|-id=key-0-1
|1
|Annuals; phyllaries 12–16; ray laminae 9–15 or 20–33 mm; disc florets 40–60 or 60–90; cypselae 5–9 mm
|[[#key-0-2| > 2]]
|-id=key-0-2
|2
|Leaf blades ± deltate to pentagonal, often 3- or 5-lobed, abaxial faces soft-pubescent; rays usually orange, rarely yellow, laminae 20–33 × 6–17 mm
|[[Tithonia rotundifolia|Tithonia rotundifolia]]
|-id=key-0-2
|2
|Leaf blades mostly deltate, rarely, if ever, lobed, abaxial faces sparsely hirsute (hairs larger on veins); rays yellow, laminae 9–15 × 4–6 mm
|[[Tithonia thurberi|Tithonia thurberi]]
|}
</div></div><!--

-->{{#Taxon:
name=Tithonia
|author=John C. La Duke
|authority=Desfontaines ex Jussieu
|rank=genus
|parent rank=subtribe
|synonyms=
|basionyms=
|family=Asteraceae
|distribution=sw United States;Mexico;Central America;in se United States;West Indies;South America;and Old World
|reference=la1982a
|publication title=Gen. Pl.,
|publication year=1789
|special status=
|source xml=https://bibilujan@bitbucket.org/aafc-mbb/fna-fine-grained-xml.git/src/84153f6d59a0a91d69695978a64cee7560374f8e/V19-20-21/V21_335.xml
|tribe=Asteraceae tribe Heliantheae
|subtribe=Asteraceae (tribe Heliantheae) subtribe Helianthinae
|genus=Tithonia
|base shape=auriculate;truncate
|blade architecture=5-nerved;3-nerved;5-nerved;3-nerved
|blade quantity=[1
|blade shape=5-lobed;3-lobed;pentagonal;deltate
|corolla coloration=yellow;orange;yellow
|cypsela shape=cuneiform;biconvex;4-angled;3-angled;flattened;compressed
|disc-floret atypical quantity=120;200
|disc-floret quantity=40;120
|disc-floret reproduction=fertile;bisexual
|face pubescence=villous;soft-pubescent;villous;soft-pubescent;pilose;hirsute;glabrate
|head arrangement=singly
|involucre diameter=10mm;20mm
|involucre shape=campanulate;hemispheric
|leaf architecture=sessile;petiolate
|leaf arrangement=alternate;opposite
|leaf position=cauline
|lobe quantity=5
|lobe shape=triangular
|pappus presence=absent
|pappus shape=coroniform
|phyllary duration=persistent
|phyllary quantity=12;28
|ray-floret architecture=neuter
|ray-floret quantity=8;30
|receptacle architecture=paleate
|receptacle shape=hemispheric;convex
|series quantity=2;5
|stem architecture=branched
|stem orientation=erect
|tube height or length or size=shorter
|ultimate margin shape=serrate;crenate
|whole-organism duration=perennial;annual
|whole_organism atypical some measurement=500cm;700cm
|whole_organism growth form=shrub;subshrub
|whole_organism some measurement=70cm;500cm
|x chromosome quantity=17
}}<!--

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