Tithonia diversifolia
Tithonia
Mexican sunflower weed, tree marigold
sunflowerweed, tithonia
erect, branched.
petioles 2–6 cm;
blades ± deltate to pentagonal, 7–33 × 7–22 cm, sometimes 3- or 5-lobed, abaxial faces glabrous to hispid-pilose.
all or mostly cauline; opposite (proximal) or mostly alternate; petiolate or sessile;
blades often (1-), 3-, or 5-nerved, mostly deltate or pentagonal [lanceolate, linear], sometimes 3- 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 gland-dotted.
7–24 cm.
campanulate to hemispheric, 10–20+ mm diam.
hemispheric to convex, paleate (paleae persistent, embracing cypselae, striate, ± 3-toothed, middle teeth larger, stiff, acute or acuminate to aristate).
7–14;
corollas yellow, laminae linear, 48–69 × 9–16 mm.
8–30, neuter;
corollas yellow or orange.
80–120+.
40–120[–200+], bisexual, fertile;
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).
16–28 in (3–)4 series, oblong to ovate;
outer 6–10 × 4–7 mm, apices rounded to acute, abaxial faces usually glabrous;
inner 10–20 × 3–10 mm, apices rounded to acute, abaxial faces glabrous.
persistent, 12–28+ in 2–5 series (linear to broadly rounded, unequal to subequal, apices acute to rounded).
borne singly (peduncles usually distally dilated, fistulose).
4–6 mm.
(black or brown) ± compressed or flattened, often 3- or 4-angled or biconvex, ± cuneiform in silhouette (sometimes with basal elaiosomes);
pappi 0, or ± coroniform (of ± connate scales, 1–2 scales sometimes subulate to aristate).
10–13 × 2–3 mm, mucros 1.5–2.5 mm.
= 17.
= 34.
Tithonia diversifolia
Tithonia
Tithonia diversifolia is widely cultivated in warm climates and may persist after plantings; a report for Louisiana was not confirmed for this treatment.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Species 11 (3 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Perennials, subshrubs, or shrubs; phyllaries 16–28; ray laminae 48–69 mm; disc florets 80–120+; cypselae 4–6 mm | T. diversifolia |
1. Annuals; phyllaries 12–16; ray laminae 9–15 or 20–33 mm; disc florets 40–60 or 60–90; cypselae 5–9 mm | → 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 | T. rotundifolia |
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 | T. thurberi |
WildflowerSearch
iNaturalist
USDA Plants Database
