Asteraceae (tribe Heliantheae) subtribe Helianthinae

Annuals, perennials, subshrubs, or shrubs, (2–)20–500 cm. Leaves usually mostly cauline, rarely mostly basal; mostly opposite (distal often alternate) or mostly alternate, rarely whorled; petiolate or sessile; blades (often 3- or 5-nerved) orbiculate or deltate to lanceolate or linear (and intermediate shapes), sometimes lobed, ultimate margins entire or toothed, faces usually hairy (often hispid to scabrellous), often gland-dotted. Heads usually radiate, sometimes discoid, borne singly or in corymbiform (paniculiform or racemiform) arrays (glomerules or second-order heads of 1–2-flowered heads in Lagascea). Calyculi 0. Involucres cylindric to hemispheric or rotate. Phyllaries persistent, 4–45(–100+) in 1–6+ series (usually distinct, ± connate in Lagascea, broadly ovate to linear, subequal or unequal). Receptacles usually flat or convex, sometimes hemispheric or conic, usually paleate (epaleate in Lagascea; paleae usually falling, sometimes persistent, mostly oblong to linear, often conduplicate, herbaceous to scarious, apices sometimes ± 3-lobed or -toothed; becoming hardened perigynia completely investing cypselae in Sclerocarpus). Ray florets 0 or 5–30(–100+), neuter, or styliferous and sterile; corollas usually yellow to orange, sometimes partly or wholly brown to purple or red-brown to reddish. Disc florets 1 (Lagascea) or 10–200(–1000+), bisexual, fertile; corollas usually yellow to orange, sometimes brown to purple or reddish to red-brown, tubes shorter than or about equaling cylindric or funnelform throats, lobes 5, ± deltate (equal); anther thecae dark or pale; stigmatic papillae usually continuous. Cypselae often ± compressed, flattened, biconvex, clavate, columnar, obovoid, obpyramidal, or prismatic (lengths usually 1–2 times diams.), glabrous or hairy (faces and/or angles); pappi 0, or (often readily falling or fragile, sometimes persistent) usually of (1–)2(–8+) (sometimes aristate) scales and/or awns, sometimes coroniform.

Distribution

Mostly subtropical, tropical, and warm-temperate New World.

Discussion

Genera 17, species 363 (8 genera, 69 species, including 1 hybrid, in the flora).

Circumscription of Helianthinae adopted here (i.e., that of H. Robinson 1981) is narrower than traditional circumscriptions (e.g., T. F. Stuessy 1977[1978]), which included genera here treated in Ecliptinae, Galinsoginae, and Rudbeckiinae.

Selected References

None.

Lower Taxa

Bahiopsis, Helianthus, Heliomeris, Lagascea, Sclerocarpus, Simsia, Tithonia, Viguiera

Key

1	Phyllaries 4–5 in ± 1 series (connate); disc florets 1(–2; the 1–2-flowered heads aggregated in glomerules or second-order heads)	Lagascea
1	Phyllaries 5–45(–100+) in (1–)2–6+ series (distinct); disc florets (10–)15–200(–1000+)	> 2
2	Receptacles paleate (each palea completely investing and falling with a cypsela, eachforming a hardened perigynium)	Sclerocarpus
2	Receptacles paleate (paleae sometimes conduplicate, ± enfolding cypselae, not forming perigynia)	> 3
3	Heads borne singly (peduncles usually distally dilated, fistulose)	Tithonia
3	Heads borne singly or in corymbiform, paniculiform, racemiform, or thyrsiform arrays (peduncles rarely, if ever, notably dilated or fistulose)	> 4
4	Cypselae flattened, thin-margined	Simsia
4	Cypselae ± compressed, biconvex, or 3- or 4-angled, often obpyramidal	> 5
5	Cypselae glabrous or glabrate; pappi 0	> 6
5	Cypselae usually ± strigose, sometimes glabrous or glabrate; pappi of 2–6+, persistent, readily falling, or tardily falling scales	> 8
6	Shrubs (leaves often lobed, lobes usually 3–9, ± linear)	Viguiera
6	Annuals or perennials (leaves not lobed)	> 7
7	Annuals; leaf blades lanceolate to linear; involucres 5–6 mm diam.;phyllaries 11–17	Helianthus
7	Annuals or perennials; leaf blades lance-linear, lanceolate, ovate, rhombic, or rhombic-ovate; involucres 6–14 mm diam.; phyllaries14–25	Heliomeris
8	Shrubs; involucres 5–9 mm diam	Bahiopsis
8	Annuals or perennials; involucres (5–)7–40+ mm diam	> 9
9	Pappi readily falling	Helianthus
9	Pappi persistent or tardily falling	Viguiera