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common sunflower, hairy leaf sunflower, sunflower

Florida sunflower

Habit Annuals, 100–300 cm. Perennials, 100–200 cm (rhizomatous).
Stems

erect, usually hispid.

(green) erect, hispid to hispidulous.

Leaves

mostly cauline; mostly alternate;

petioles 2–20 cm;

blades lance-ovate to ovate, 10–40 × 5–40 cm, bases cuneate to subcordate or cordate, margins serrate, abaxial faces usually ± hispid, sometimes gland-dotted.

cauline; usually opposite or alternate, rarely whorled;

petioles 0–1 cm;

blades (1- or 3-nerved) lanceolate to elliptic or lance-ovate, 4–15 × 0.5–6 cm, bases rounded to cuneate, margins entire or serrulate (often undulate, often ± revolute), faces ± scabrous to tomentulose and gland-dotted (abaxial) or scabrous (adaxial).

Peduncles

2–20 cm.

2–15 cm.

Involucres

hemispheric or broader, 15–40(–200+) mm diam.

± hemispheric, 12–19 × 7–9 mm.

Ray florets

(13–)17–30(–100+);

laminae 25–50 mm.

10–20;

laminae 20–25 mm (abaxial faces gland-dotted).

Disc florets

150+(–1000+);

corollas 5–8 mm (throats ± bulbous at bases), lobes usually reddish, sometimes yellow;

anthers brownish to black, appendages yellow or dark (style branches yellow).

90+;

corollas 4–5 mm, lobes usually reddish, sometimes yellow;

anthers dark brown or black, appendages dark (style branches yellow).

Phyllaries

20–30(–100+), ovate to lance-ovate, 13–25 × (3–)5–8 mm, (margins usually ciliate) apices abruptly narrowed, long-acuminate, abaxial faces usually hirsute to hispid, rarely glabrate or glabrous, usually gland-dotted.

33–38, lanceolate, 5–9 × 1.5–3 mm, apices (at least outer) obtuse, abaxial faces hispidulous to hispid, gland-dotted.

Heads

1–9.

1–6.

Cypselae

(3–)4–5(–15) mm, glabrate;

pappi of 2 lanceolate scales 2–3.5 mm plus 0–4 obtuse scales 0.5–1 mm.

2.5–3 mm, glabrous;

pappi of 2 aristate scales 1.5–2.2 mm.

Paleae

9–11 mm, 3-toothed (middle teeth long-acuminate, glabrous or hispid).

4.5–6 mm, entire or weakly 3-toothed (apices purplish, glabrate to puberulent, often gland-dotted).

2n

= 34.

= 34.

Helianthus annuus

Helianthus floridanus

Phenology Flowering summer–fall. Flowering late summer to fall.
Habitat Open areas Sandy, open areas
Elevation 0–3000 m (0–9800 ft) 0–50 m (0–200 ft)
Distribution
from FNA
AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NS; NT; ON; PE; QC; SK; SPM; Mexico; intoduced nearly worldwide
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA; LA; NC; SC
[BONAP county map]
Discussion

Helianthus annuus is widely distributed, including weedy, cultivated, and escaped plants. It is the only native North American species to become a major agronomic crop. Despite its considerable variability, attempts have failed to produce a widely adopted infraspecific system of classification. Forms with red-colored ray laminae, known from cultivation and occasionally seen escaped, trace their ancestry to a single original mutant plant. It hybridizes with many of the other annual species.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Helianthus floridanus is similar to and intergrades with H. angustifolius, which has narrower leaves, and H. simulans, which is more robust and has longer leaves without undulate margins.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 21, p. 149. FNA vol. 21, p. 164.
Parent taxa Asteraceae > tribe Heliantheae > subtribe Helianthinae > Helianthus Asteraceae > tribe Heliantheae > subtribe Helianthinae > Helianthus
Sibling taxa
H. agrestis, H. angustifolius, H. anomalus, H. argophyllus, H. arizonensis, H. atrorubens, H. bolanderi, H. californicus, H. carnosus, H. ciliaris, H. cusickii, H. debilis, H. decapetalus, H. deserticola, H. divaricatus, H. eggertii, H. exilis, H. floridanus, H. giganteus, H. glaucophyllus, H. gracilentus, H. grosseserratus, H. heterophyllus, H. hirsutus, H. laciniatus, H. laevigatus, H. longifolius, H. maximiliani, H. microcephalus, H. mollis, H. neglectus, H. niveus, H. nuttallii, H. occidentalis, H. paradoxus, H. pauciflorus, H. petiolaris, H. porteri, H. praecox, H. pumilus, H. radula, H. resinosus, H. salicifolius, H. schweinitzii, H. silphioides, H. simulans, H. smithii, H. strumosus, H. tuberosus, H. verticillatus, H. ×laetiflorus
H. agrestis, H. angustifolius, H. annuus, H. anomalus, H. argophyllus, H. arizonensis, H. atrorubens, H. bolanderi, H. californicus, H. carnosus, H. ciliaris, H. cusickii, H. debilis, H. decapetalus, H. deserticola, H. divaricatus, H. eggertii, H. exilis, H. giganteus, H. glaucophyllus, H. gracilentus, H. grosseserratus, H. heterophyllus, H. hirsutus, H. laciniatus, H. laevigatus, H. longifolius, H. maximiliani, H. microcephalus, H. mollis, H. neglectus, H. niveus, H. nuttallii, H. occidentalis, H. paradoxus, H. pauciflorus, H. petiolaris, H. porteri, H. praecox, H. pumilus, H. radula, H. resinosus, H. salicifolius, H. schweinitzii, H. silphioides, H. simulans, H. smithii, H. strumosus, H. tuberosus, H. verticillatus, H. ×laetiflorus
Synonyms H. annuus subsp. jaegeri, H. annuus subsp. lenticularis, H. annuus var. lenticularis, H. annuus var. macrocarpus, H. annuus subsp. texanus, H. aridus, H. jaegeri, H. lenticularis, H. macrocarpus
Name authority Linnaeus: Sp. Pl. 2: 904. (1753) A. Gray ex Chapman: Fl. South. U.S. ed. 2, 629. (1883)
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