Asteraceae (tribe Heliantheae) subtribe Helianthinae
Fl. Belg., 71. 1827.
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.
Mostly subtropical, tropical, and warm-temperate New World.
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), which included genera here treated in Ecliptinae, Galinsoginae, and Rudbeckiinae.
|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|