Asteraceae tribe Heliantheae
J. Phys. Chim. Hist. Nat. Arts 88: 189. 1819.
Annuals, biennials, perennials, subshrubs, shrubs, or trees. Leaves usually cauline, sometimes mostly basal or basal and cauline; usually wholly or partly opposite, sometimes mostly whorled or alternate; usually petiolate, sometimes sessile; margins entire or dentate to pinnatifid or palmatifid (faces often gland-dotted). Heads usually heterogamous (disciform or radiate), sometimes homogamous (usually discoid, sometimes ± radiant; unisexual in some genera), usually in corymbiform, paniculiform, racemiform, or spiciform arrays, sometimes borne singly or in glomerules, rarely aggregated in second-order heads. Calyculi 0 or of 1–15+ bractlets. Phyllaries persistent or falling, usually in 3–5+ series, usually distinct (sometimes connate and forming hardened perigynia or winged or tuberculate to spiny burs, e.g., Ambrosia spp.), unequal (usually lanceolate to ovate or broader), and herbaceous to chartaceous with margins and/or apices sometimes notably scarious, sometimes in 1–2 series, distinct or connate, subequal (usually linear to lanceolate), and herbaceous with margins and/or apices sometimes notably scarious. Receptacles flat to conic or cylindric, paleate or epaleate (sometimes with enations from receptacles among florets, e.g., some Gaillardia spp.; sometimes pitted, pit borders often fimbrillate to lacerate). Ray florets (rarely 0) usually in 1(–2+) series, usually pistillate, rarely neuter or styliferous and sterile; corollas usually yellow to orange, sometimes cyanic to red, dark brown, or purplish, or white (laminae sometimes marcescent, e.g., Baileya, Zinnia). Peripheral (pistillate) florets 0 or (in disciform heads) in 1–3+ series; corollas (usually present) usually yellow to orange, sometimes ochroleucous or cyanic to reddish, purplish, or brown. Disc (inner) florets usually bisexual and fertile, rarely functionally staminate; corollas usually yellow to orange, sometimes ochroleucous or cyanic to reddish, purplish, or brown, sometimes ± zygomorphic (± 2-lipped), lobes (3–)5, usually ± deltate to lance-ovate, sometimes lanceolate to lance-linear; anther bases obtuse or rounded, not tailed (sometimes sagittate), apical appendages usually ovate to lanceolate, rarely 0 (in Ambrosiinae, filaments usually connate, anthers distinct, and plants wind-pollinated); styles abaxially glabrous or papillate to hirsutulous (distally), branches linear, adaxially stigmatic, usually in 2 lines, sometimes continuously, from bases to appendages, appendages usually deltate to lanceolate (abaxially and adaxially papillate to hispidulous). Cypselae usually monomorphic, sometimes dimorphic within heads, usually ± columnar to prismatic, sometimes compressed, obcompressed, or flattened, sometimes ± beaked, bodies smooth, rugose, tuberculate, ribbed, or winged (glabrous or hairy; cypselae enclosed within and shed with a hardened perigynium or bur in some Ambrosiinae; enfolded within and shed with subtending phyllaries or paleae in some Madiinae and genera in other subtribes); pappi (rarely 0) usually persistent, sometimes readily falling, usually of scales (scales sometimes aristate, sometimes plumose), sometimes of awns or smooth, or barbellulate to barbellate, or plumose bristles, sometimes combinations of scales and/or awns and/or bristles.
Distribution
Almost wholly New World, mostly subtropical, tropical, and warm-temperate.
Discussion
Genera ca. 300, species ca. 3300+ (148 genera, 746 species, including 5 hybrids, in the flora).
Nearly 95% of the species of Heliantheae in the broad sense (both paleate and epaleate genera) are native in the New World. O. Hoffmann (1890–1894) listed 10 subtribes for Heliantheae in a restricted sense (only paleate genera). T. F. Stuessy (1977[1978]) listed 15 subtribes for his Heliantheae, which included transfer of much (but not all) of traditional Helenieae (epaleate genera), as Bahiinae and Gaillardiinae. H. Robinson (1981) listed 35 subtribes for Heliantheae, including transfers of all of traditional Helenieae plus some genera formerly included in Senecioneae (e.g., Arnica). Because Robinson’s classification of Heliantheae was current and available as plans were being laid for treating the composites for this flora (ca. 1988), it was chosen as the organizational basis for the tribe.
P. O. Karis and O. Ryding (1994, 1994b) tentatively segregated the paleate and epaleate genera of Heliantheae s.l. as Heliantheae s.str. and Helenieae, respectively–-a traditional split but with a novel circumscription of Helenieae. Other authors have suggested separating genera of Heliantheae in a broad sense into a dozen or so tribes (e.g., B. G. Baldwin and B. L. Wessa 2000; Baldwin et al. 2002; J. L. Panero and V. A. Funk 2002).
Much of the partitioning and reorganizing of Heliantheae in the past 20 or so years has stemmed from botanists comparing differences and similarities in base sequences in DNA molecules and seeking to have taxa correspond to monophyletic clades. Some botanists see a phylogenetic classification comprising monophyletic taxa as the ultimate goal of systematics (e.g., P. C. van Welzen 1997); other botanists see monophyletic taxa as logically, philosophically, and/or theoretically untenable (e.g., R. K. Brummitt 1997).
Selected References
Lower Taxa
Key
| 1 | Receptacles usually wholly epaleate (rarely bearing conic to setiform enations, e.g., Gaillardia in Gaillardiinae, or ± membranous paleae, e.g., Amblyolepis setigera in Gaillardiinae, Chaenactis carphoclinia in Chaenactidinae, and Eriophyllum ambiguum in Baeriinae; see also, first lead of couplet 11, Madiinae; receptacles deeply pitted in Balduina in Gaillardiinae, the pit borders sometimes interpreted as coalesced paleae) | > 2 |
| 1 | Receptacles wholly or partly paleate | > 11 |
| 2 | Leaves and/or phyllaries dotted or streaked with pellucid (schizogenous) glands containing strong-scented oils | Pectidinae |
| 2 | Leaves and/or phyllaries rarely dotted or streaked (never with pellucid, schizogenous glands containing strong-scented oils, plants sometimes with sessile or stipitate, surface glands and sometimes strong-scented) | > 3 |
| 3 | Annuals 1–5 cm; phyllaries 2–3; ray florets 0; disc florets 2–3; pappi of ca. 20 basally connate, subulate, plumose scales | Dimeresiinae |
| 3 | Annuals, perennials, subshrubs, or shrubs, (1–)5–200(–300) cm; phyllaries 2–50+; ray florets 0 or (1–)4–21(–60+); disc florets (1–)5–60(–300); pappi 0 or of smooth to barbellate (rarely, if ever, plumose) awns, bristles, and/or scales | > 4 |
| 4 | Leaves (often somewhat succulent) opposite, sessile or nearly so, blades usually oblong to linear or filiform (not lobed); cypselae clavate to cylindric and 8–15-ribbed | > 5 |
| 4 | Leaves (seldom succulent) opposite or alternate, petiolate or sessile, blades often lobed; cypselae usually obpyramidal to obconic, sometimes columnar or flattened, seldom clavate or cylindric, often 4–5-angled (not both clavate to cylindric and 8–15-ribbed; sometimes cylindric and 5–10-nerved, e.g., Chaenactidinae, Arnica spp.) | > 7 |
| 5 | Phyllaries 2–5 in 1 series, subequal | Flaveriinae |
| 5 | Phyllaries 12–16+ in 2–3+ series, unequal | > 6 |
| 6 | Cypselae hairy; pappi of 12–25, or ca. 50 bristles or setiform to subulate scales | Clappiinae |
| 6 | Cypselae glabrous; pappi usually 0, sometimes 1–5 (minute) subulate scales | Jaumeinae |
| 7 | Phyllaries often ± conduplicate and navicular; disc corollas usually 4-lobed; cypselae strongly flattened or weakly 3–4-angled, usually callous-margined, often ciliate | Peritylinae |
| 7 | Phyllaries usually flat to weakly navicular; disc corollas (4–)5-lobed; cypselae usually obpyramidal to obconic, sometimes columnar, seldom clavate or cylindric, often 4–5-angled (seldom strongly compressed or flattened, callous-margined, and ciliate) | > 8 |
| 8 | Cypselae stoutly obconic to obpyramidal (lengths usually 1–2, rarely to 3.5 times diams.) | > 9 |
| 8 | Cypselae narrowly clavate or columnar to obconic or obpyramidal (lengths usually 3+ times diams., if stouter, usually ± compressed) | > 10 |
| 9 | Phyllaries: margins usually notably membranous to scarious; disc corollas usually whitish, sometimes purplish or yellowish (tubes, throats, and lobes glabrous or hairy, hairs not moniliform); cypselae usually 4-angled and 12–16-ribbed | Hymenopappinae |
| 9 | Phyllaries: margins seldom scarious; disc corollas orange to yellow or partly or wholly purple-brown or reddish (tubes, throats, and lobes often hairy, hairs often moniliform); cypselae usually obpyramidal, sometimes clavate, columnar, or obconic (not both 4-angled and 12–16-ribbed) | Gaillardiinae |
| 10 | Leaves usually sessile, sometimes obscurely petiolate (rarely truly petiolate); pappi 0, or of scales (scales not medially thickened) | Baeriinae |
| 10 | Leaves usually petiolate (± sessile in some spp. of Arnica, Chaenactis, Hulsea); pappi 0, or of scales (scales usually notably medially thickened) | Chaenactidinae |
| 11 | Heads disciform or discoid; pistillate florets: corollas sometimes none (cypselae shed with accessory structures or within burs); staminate florets: anthers usually distinct (staminal filaments coherent or connate in some spp.) | Ambrosiinae |
| 11 | Heads usually disciform, discoid, or radiate; pistillate florets: corollas usually present (cypselae seldom shed with accessory structures, sometimes shed within perigynia, each formed from single phyllary, not shed within burs); bisexual florets: anthers usually connate (staminal filaments usually distinct) | > 12 |
| 12 | Plants often with tack-glands or pit-glands on stems, leaves, and/or phyllaries; phyllaries (or paleae functioning as phyllaries) usually in 1+ series (each often wholly or partly investing ovary of subtended floret); paleae often in 1 series between ray and disc florets, often connate in a ring, sometimes each disc floret subtended by palea; ray corolla laminae often flabellate (lobes often 1/2+ lengths of laminae); pappi usually of coarse, plumose and/or woolly bristles or subulate, plumose and/or woolly scales, sometimes none | Madiinae |
| 12 | Plants without tack-glands or pit glands; phyllaries in (1–)2–7+ series (seldom each inner phyllary wholly or partly investing ovary of subtended floret); paleae seldom restricted to 1 series between ray and disc florets, all or nearly all disc florets subtended by paleae; laminae of ray corollas seldom flabellate (lobes mostly 0–1/10 lengths of laminae); pappi usually of awns, bristles, and/or scales (seldom plumose), sometimes 0 | > 13 |
| 13 | Calyculi usually of 3–8(–21+) bractlets or bracts, sometimes 0; phyllaries usually in ± 2 series, usually ± equal; disc cypselae obcompressed to obflattened (often winged), or ± equally 4-angled and fusiform to linear | Coreopsidinae |
| 13 | Calyculi usually 0; phyllaries in 1–7+ series; disc cypselae seldom obcompressed or 4-angled and fusiform to linear | > 14 |
| 14 | Phyllaries (at least inner) usually falling with cypselae; ray florets 0 or pistillate and fertile | > 15 |
| 14 | Phyllaries persistent (in fruit); ray florets 0 or pistillate and fertile, or styliferous and sterile, or neuter | > 18 |
| 15 | Disc florets bisexual and fertile; anther thecae pale; pappi of subulate, often ± plumose scales or bristles | Galinsoginae (Galinsoga) |
| 15 | Disc florets usually functionally staminate (bisexual and fertile in Milleriinae, Guizotia); anther thecae usually dark (blackish to purplish); pappi 0 | > 16 |
| 16 | Ray florets 6–18 (corollas hairy at bases of tubes); disc florets bi-sexual, fertile. | Milleriinae |
| 16 | Ray florets 3–20+ (corollas seldom hairy at bases of tubes); disc florets functionally staminate | > 17 |
| 17 | Cypselae each shed with associated paleae and/or florets | Ambrosiinae |
| 17 | Cypselae each shed with (and enclosed within) a phyllary or shed without accessory structures | Melampodiinae |
| 18 | Receptacles spheric to high-conic or columnar (mostly 8–20+ mm) | > 19 |
| 18 | Receptacles mostly flat to convex or conic (mostly 0–5 mm) | > 20 |
| 19 | Phyllaries subequal or unequal (outer usually longer than inner); ray florets 0 or 3–21+, neuter; disc florets 100–200+, bisexual and fertile; stigmatic papillae usually in 2 lines; pappi usually 0 or coroniform (vestigial), rarely of 2–4 scales | Rudbeckiinae |
| 19 | Phyllaries subequal or unequal (outer usually shorter, rarely longer, than inner); ray florets 0 or 3–40+, usually pistillate and fertile, sometimes styliferous and sterile, or neuter; disc florets 4–200+, usually bisexual and fertile, sometimes functionally staminate; stigmatic papillae usually continuous, rarely in 2 lines; pappi usually of scales, sometimes of bristles, rarely of awns or 0 | Ecliptinae |
| 20 | Leaves mostly cauline and alternate (proximal sometimes opposite), or mostly opposite (distal sometimes alternate); ray florets usually neuter, or styliferous and sterile, sometimes 0; pappi 0 or of (fragile or caducous) scales or awns | > 21 |
| 20 | Leaves usually cauline and opposite, sometimes mostly basal and/or mostly alternate; ray florets usually pistillate and fertile (if neuter, leaves mostly basal or alternate), sometimes 0; pappi usually persistent, usually of awns, bristles, and/or scales, sometimes 0 | > 23 |
| 21 | Phyllaries 45–60 in 4–5 series (resin-nerved); anther thecae pale; stigmatic papillae in 2 lines; cypselae clavate to columnar and 8–15-ribbed | Varillinae |
| 21 | Phyllaries 4–35+ in 1–6+ series; anther thecae dark; stigmatic papillae continuous; cypselae clavate to columnar or prismatic (3–4-angled), or compressed to flattened | > 22 |
| 22 | Disc corollas yellow (bases often dilated, clasping tops of ovaries) | Zaluzaniinae |
| 22 | Disc corollas yellow to orange or brown-purple (bases not clasping tops of ovaries) | Helianthinae |
| 23 | Disc florets functionally staminate | > 24 |
| 23 | Disc florets bisexual and fertile | > 26 |
| 24 | Anther thecae green (staminal filaments hairy); Arizona | Guardiolinae |
| 24 | Anther thecae dark or pale (not green, staminal filaments not hairy); e, se United States | > 25 |
| 25 | Ray florets 7–13, corollas yellow; disc florets 40–80; cypselae (obliquely inserted on receptacles) 30–40-ribbed or -nerved (not beaked) | Melampodiinae |
| 25 | Ray florets 2–6, corollas pale yellow to whitish; disc florets 12–30+; cypselae (patently inserted on receptacles) 3–6-ribbed or -nerved (finely striate between ribs, apices often minutely beaked) | Polymniinae |
| 26 | Disc corollas lavender, pink, purple, or white; anther thecae cream to purple | Marshalliinae |
| 26 | Disc corollas usually orange to yellow, sometimes brown, pink, purple, red, or white; anther thecae pale or dark (not violet) | > 27 |
| 27 | Heads discoid; pappi of 15–30, ± plumose bristles or subulate scales (desert shrubs, leaf blades mostly linear-filiform) | Galinsoginae |
| 27 | Heads discoid or radiate; pappi 0 or of awns, bristles, or (seldom plumose) scales | Ecliptinae |