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Key to Asteraceae, Key C: herbaceous composites with opposite leaves and radiate heads

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1 Ray florets white, pink, or purple (rarely pale yellow or lavender).
  2 Ray floret (the lamina) persistent on the achene and becoming papery and bleached
  2 Ray floret (the lamina) articulate from the achene and falling, thus the mature heads not appearing papery.
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Show caption*© Scott Ward
    3 Pappus of a minute crown (coroniform); disc florets white or whitish.
    3 Pappus not only coroniform, either absent or variously composed of scales, awns, or plumose bristles (Galinsogeopsis has 2 antrorsely barbed bristles plus a crowns of laciniate scales); disk florets yellow, red-brown, or pinkish.
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Show caption*© Sonnia Hill
      4 Heads with an involucre not subtended by a calyculus.
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Show caption*© Sonnia Hill
        5 Rays pink, the laminae 5-14 mm long; [OK and TX westward; subtribe Cheaenactidinae]
        5 Rays white or whitish-yellow; the laminae shorter, typically < 5 mm long (occasionally longer in Polymnia).
          6 Plants larger, 50-150+ cm tall; perennials; leaves > 10 cm long, sometimes with winged petioles or clasping basal appendages; disc florets functionally staminate; [natives of higher-quality, limestone or novaculite habitats; subtribe Polymniinae]
          6 Plants smaller, 2-40 cm tall or long (if stems > 40 cm then plants usually procumbent or decumbent); annuals or perennials; leaves usually < 10 cm long, lacking winged petioles or clasping basal appendages; disc florets bisexual and fertile.
             7 Stems usually copiously glandular-pubescent; leaf blades cordate to subdeltate or usually strongly 3-lobed (but not pinnate), the margins singly or doubly crenate; disc florets 40-100+; plants erect to decumbent; [native, s. TX westward; subtribe Peritylinae]
             7 Stems not copiously glandular-pubescent; leaf blades lanceolate to broadly ovate or deltate, or pinnately to palmately lobed (Tridax); plants erect or ascending to procumbent (Tridax]; [non-natives of disturbed habitats, widespread; subtribe Galinsoginae].
               8 Plants with leaves simple, unlobed; pappus either absent or of 5-20 laciniate or fimbriate scales; plants annual, erect
               8 Plants usually with a mix of simple and 3-lobed leaves; pappus usually of ca. 20 plumose (or setiform) scales; plants perennial, usually at least somewhat procumbent
      4 Heads with an involucre subtended by a calyculus of bracts (these often but not always reflexed); the phyllaries often appearing somewhat translucent or of a distinctly different color, shape, or texture from the leafy colored bracts below; [tribe Heliantheae; subtribe Coreopsidinae].
                 9 Phyllaries connate for at least ¼ their length; heads with or without ray florets; [MS westwards in our area]
                 9 Phyllaries distinct; heads with ray florets; [collectively widespread in our area].
                   10 Cypselas beaked, not strongly flattened, 7-30 mm long, with 1 groove per face; leaves highly dissected
                   10 Cypselas beakless, more or less strongly flattened and also often winged, 1.2-16 mm long, with 0 or 2 grooves per face; leaves simple to highly dissected.
                     11 Cypselas 2.5-16 mm long, usually not winged; pappus awns (if present) usually retrorsely barbed; rays white
                     11 Cypselas 1.2-4 mm long, winged (C. nudata) or not (C. rosea); pappus awns (if present) barbless; rays pink, purple, or white
1 Rays predominantly yellow, orange, or red (sometimes with some brown, maroon, or purple coloration as well).
                       12 Receptacle naked, epaleate.
                          13 Leaves and phyllaries with large, scattered, embedded oil glands, making the plants strongly aromatic (the glands translucent in living plants, usually golden-brown or blackish in herbarium specimens); plants annual, decumbent and much branched from the base (except Tagetes, annual and generally erect and sparingly branched); [tribe Heliantheae; subtribe Pectidinae].
                            14 Leaves unlobed, entire or serrate.
                              15 Leaves coarsely toothed, mostly opposite (the distal alternate)
                              15 Leaves entire (though with marginal setae), opposite
                            14 Leaves pinnately lobed or pinnatisect (pinnately divided nearly to the midrib but the leaflets not separate), the margins of terminal segments usually serrate (sometimes entire).
                                16 Pinnate leaf segments lanceolate, 3-10 mm wide; calyculus absent
                                16 Pinnate leaf segments linear, 1-3 mm wide; calyculus present, of linear bracts and subtending the involucre.
                                  17 Phyllaries distinct to their bases, or nearly so; ray florets 5-8; heads borne singly or in pairs/triplets; leaf surfaces puberulent
                                  17 Phyllaries connate > ½ their length; ray florets 5-21; heads borne singly; leaf surfaces glabrous to variously pubescent/floccose
                          13 Leaves and phyllaries lacking embedded oil glands, though smaller punctate glands sometimes present; perennial or annual plants, upright and little or moderately branched below the inflorescence.
                                    18 Leaf surfaces densely scabrous and canescent; [s. TX westward]
                                    18 Leaf surfaces glabrous to hirsute but never canescent; [collectively widespread]
                                       19 Leaves mainly basal or basally disposed (a few pairs low on the stem), the blades elliptic to ovate, the surfaces hirsute and stipate-glandular
                                       19 Leaves mainly cauline, the blades primarily linear, lanceolate oblanceolate, or occasionally oblong (if ovate, then leaves mostly cauline), the surfaces glabrous to strigose but not stipitate-glandular
                                         20 Pappus absent or of 1-2 antrorsely-barbed or subplumose bristles; leaf blades usually lobed; [c. and TX westward; formerly Perityle]
                                         20 Pappus absent, of scales, or coroniform (if coroniform then with 6-8 barbellulate bristles as in Jamesianthus); leaf blades unlobed; collectively widespread, including c. TX]
                                           21 Heads smaller and many (10-300+), arranged into dense, flat-topped corymbs; disc florets 1-15; ray florets 0-2, the laminae inconspicuous; phyllaries 6 (-9), in 1 series; [collectively more widespread but absent from n. AL and wc. GA]
                                           21 Heads larger and fewer (< 9 per inflorescence), arranged singly or in loose corymbs; ray florets 6-14, the laminae conspicuous; phyllaries 12-18, broadly ovate, squarrose and in several imbricate series; [on calcareous substrates in n. AL and wc. GA]
                       12 Receptacle paleate, with paleae, bristles, or scales.
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Show caption*© Scott Ward
                                             22 Disc florets functionally staminate (“sterile”, not producing cypselae), the style undivided, their ovaries much smaller than ovaries of the ray florets (which are functionally pistillate).
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Show caption*© Swarochi Tathagath, some rights reserved (CC BY), uploaded by Swarochi Tathagath
                                               23 Inner phyllaries prickly with straight or uncinate prickles, and each enveloping a cypsela and swelling into a bur-like structure
                                               23 Inner phyllaries unarmed, not becoming bur-like (though those of Melampodium do invest the fruit).
                                                 24 Plants with tack-glands or pit-glands on stems, leaves, and/or phyllaries; [waif, e. TX; native further westward]
                                                 24 Plants without tack-glands or pit glands.
                                                    25 Outer phyllaries orbicular, connate 1/4 - 1/3 of their lengths; [exotic, rare]
                                                    25 Outer phyllaries orbicular to lance-linear, not connate; [native, collectively widespread in our area].
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Show caption*© Gary P. Fleming
                                                      26 Phyllaries in 2 series; pappus coroniform (Chrysogonum) or absent (Lindheimera)
                                                        27 Plants perennial, often trailing; pappus persistent, forming a minute, half-cup-shaped crown; [e. LA eastward, e. of MS river]
                                                        27 Plants annual, erect; pappus absent (cypselae with 2 pappus-like processes originating from cypsela wings); [w. LA westward, w. of MS river]
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Show caption*© Alan M. Cressler
                                                      26 Taller, robust plants, the stems usually 5-40 cm long at maturity, erect; pappus absent or of 2 awns.
image of plant
Show caption*© Scott Ward
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Show caption*© Scott Ward
                                                          28 Cypselae thick, not flattened, borne in 1 series from the 1 series of ray florets
                                             22 Disc florets functionally bisexual (“fertile”, producing cypselae), the style divided, their ovaries as large as, or larger than, ovaries of the ray florets (which may be either functionally pistillate or completely neuter).
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Show caption*© Scott Ward
                                                            29 Ray corolla (the lamina) persistent on the achene and becoming papery and bleached.
                                                              30 Outer phyllaries with a stiff, maroon-colored subulate apex
                                                              30 Outer phyllaries lacking a stiff subulate apex.
                                                                 31 Leaf margins serrate or toothed; plant a perennial; cypselae subterete, 4-5 mm long; [natives]
                                                                 31 Leaf margins entire; plant an annual; cypselae 3-angled or flattened, 6-10 mm long; [non-native waifs]
                                                            29 Ray corolla articulate from the achene and falling after flowering.
                                                                   32 Pappus of 20 plumose bristles 4-5 (-7.5) mm long
                                                                   32 Pappus absent or of scales or awns (if with awnlike bristles as in Acmella, then these never plumose).
                                                                     33 Plants with tack-glands or pit-glands on stems, leaves, and/or phyllaries; [waif, VA and NC northward; subtribe Madiinae]
                                                                     33 Plants without tack-glands or pit-glands on stems, leaves, and/or phyllaries; [natives and non-natives, collectively widespread]
                                                                       34 Paleae not notably clasping the cypsela; cypselae notably flattened (or weakly compressed/angled in Guizotia); heads small, the receptacle 3-8 mm in diameter (ca. 10-15 mm in Guizotia).
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Show caption*© Scott Ward
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Show caption*© Daniel Cahen, some rights reserved (CC BY), uploaded by Daniel Cahen
                                                                         35 Pappus absent; ray laminae longer, 8-14 mm long
                                                                         35 Pappus persistent, of 2-3(-5) scales or awns; ray laminae shorter, 2-5 mm long.
                                                                           36 Cypselae of two types, strongly dimorphic: those of the rays smooth and flattened, the margins conspicuously lacerate and the pappus awns reduced in length; those of the discs ribbed and muricate, with 2 lengthened and divergent awns
                                                                           36 Cypselae of the rays and discs similar, monomorphic and not as above (the achenes weakly dimorphic in C. vialis, but the apical awns of similar length and the margins with only small, inconspicuous winglike projections)
                                                                       34 Paleae either entirely enveloping and falling with each cypsela or conduplicate (V-shaped in cross section), the 2 sides of the V partially clasping the cypsela; cypselae flattened, terete, or angled; heads mostly larger.
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Show caption*© Richard & Teresa Ware
                                                                              37 Phyllaries apparently 4, the outer 4 foliaceous and forming a fused quadrangle which conceals the much smaller and narrower inner phyllaries (each inner phyllary subtending a ray floret); cypselae finely 32-40 ribbed
                                                                              37 Phyllaries not as above, instead 5 or more and not forming a conspicuously fused quandrangle; cypselae angled or smooth (sometimes angled, but lacking many fine ribs)
                                                                                38 Paleae completely surrounding the cypselae of the disc florets, forming a perigynium or sac-like appendage
                                                                                38 Paleae conduplicate or partially enclosing the cypselae, but not forming a sac-like appendage.
                                                                                  39 Disc florets with hairy staminal filaments; pappus of 4-6 aristate to lacerate scales; [TX westward]
                                                                                  39 Disc florets without hairy staminal filaments; pappus absent or of 2-3 scales or awns (sometimes accompanied by up to 8-12 additional shorter scales in Helianthus and Simsia, but these readily falling); [collectively widespread].
                                                                                    40 Rays primarily orange; [waif of FL, AL, and LA]
                                                                                    40 Rays primarily yellow; [natives and non-natives, collectively widespread]
                                                                                      41 Cypselae (of at least the disc florets) strongly flattened and generally also winged (thin-margined in Simsia).
                                                                                        42 Cypselae 3-7 mm long; erect herbs; stems often winged
                                                                                        42 Cypselae 1-2.5 mm (Acmella) or 3.5-6 mm long (Simsia); plants erect, decumbent, or prostrate; stems never winged.
                                                                                           43 Phyllaries 8-15; cypselae 1-2.5 mm long; involucre ca. 3-6 mm in diameter
                                                                                           43 Phyllaries 13-43; cypselae 3.5-6 mm long; involucre 5-16+ mm in diameter
                                                                                      41 Cypselae subterete, quadrangular, variously angled, or diamond-shaped in ×-section, not winged.
                                                                                             44 Ray florets pistillate (“fertile”).
                                                                                               45 Erect herb; leaves entire or with a few teeth; peduncles < 3 cm long
                                                                                               45 Creeping herb; leaves serrate and also mostly 3-lobed; peduncles 3-10 cm long
                                                                                             44 Ray florets completely neuter.
                                                                                                 46 Leaves linear; plants perennial with woody caudices; pappus absent; leaf surfaces and ray laminae abaxially gland-dotted; [SC waif; native to sw. US]
                                                                                                 46 Leaf blades usually broader (if linear, leaves either whorled or pappus present); plants annual or perennial, with or without woody caudices; pappus typically of scales or awns; [collectively widespread in our flora area].
                                                                                                   47 Leaves linear, lanceolate, or ovate, almost always some leaves on a plant > 7 mm wide; plants from crowns, some species with thickened vertical storage roots (only H. tuberosus producing horizontal tubers); [collectively widespread in our area]
                                                                                                   47 Leaves linear, 0.5-7 mm wide; plants from slender horizontal tubers; [c. FL north to s. AL]

Key to Asteraceae, Key J: Herbaceous composites with the leaves alternate or basal and the heads radiate, the rays yellow, orange, red

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1 Disc florets functionally staminate (sterile), with style undivided.
  2 Phyllaries 10 or less, in 2 series; plants annual; [primarily OK and TX]
  2 Phyllaries 12 or more, in (2-) 3-4 series; plants perennial; [collectively widespread, including OK and TX in our area]
    3 Cypselae with broad wings with 2 confluent awns
    3 Cypselae not winged, pappus absent or of 2-4 ciliate scales.
      4 Disc florets green, red, or maroon; pappus absent; leaves lanceolate, lyrate, or lyrate-pinnatifid (but not deeply pinnatifid); [nc. TX westward]
      4 Disc florets primarily yellow; pappus of 2-4 ciliate scales; leaves deeply pinnatifid [sw. AR and e. TX westward, waif in e. LA]
1 Disc florets bisexual (fertile), with style bifurcate.
        5 Leaves decurrent down the stem (the stem appearing winged); cypselae strongly flattened and often winged
        5 Leaves not decurrent; cypselae moderately compressed to 4-angled, not winged (or if winged, the cypselae obcompressed or obconic).
          6 Receptacular bracts connate to form a honeycomb-like structure in which the flowers are set; pappus of 7-12 scales
          6 Receptacular bracts not fused and not forming a honeycomb-like structure; pappus absent, of awns/scales, or a fused crown (Phoebanthus sometimes with up to 4 additional scales shorter than 2 primary lacerate scales).
             7 Heads subtended by a calyculus (bracts distinct from phyllaries)
             7 Heads without a calyculus.
               8 Leaves conspicuously clasping the stem
               8 Leaves not noticeably clasping the stem.
                 9 Leaves pinnately lobed, the primary lobes usually pectinately divided; [non-native]
                 9 Leaves unlobed or if pinnatifid to pinnately lobed, the primary lobes not pectinate; [natives].
image of plant
Show caption*© Scott Ward
                   10 Pappus of 2 caducous, or readily-falling scales; receptacles flat
                   10 Pappus absent, or of 1-2 lacerate scales (on shoulders of cypselae) plus additional lacerate (bristlelike) scales; receptacles subspheric, conical, columnar, or otherwise convex.
                     11 Receptacle low conic to convex; phyllaries (14-) 20-40+, in 2-3 series.
                       12 Leaf blades linear; plants from slender, horizontal tubers; pappus absent or of 1-2 lacerate scales (on shoulders of cypselae) plus additional lacerate (bristlelike) scales; [natives of AL and FL; subtribe Ecliptinae]
                       12 Leaf blades variously shaped, not all linear (often with some ovate or rhombic leaves); plants from woody caudices; pappus absent; [waif in SC, native in arid southwest; subtribe Helianthinae]
                     11 Receptacle strongly conic or columnar; phyllaries 3-21, in 1-2 series; [subtribe Rudbeckiinae].
                          13 Phyllary series unequal (outer longer than inner); cypselae strongly compressed; ray florets subtended by receptacular bracts
                          13 Phyllary series subequal; cypselae not strongly compressed; ray florets not subtended by receptacular bracts (only the disc flowers with bracts)

Key to Asteraceae, Key L: Herbaceous composites with the leaves alternate or basal and the heads radiate, the rays white, pink, purple, and the 0 pappus

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1 Rays primarily pink or purple, not white-tinged (flowers viewed from above, adaxial surface of the rays).
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Show caption*© Jacek Pietruszewski, some rights reserved (CC BY), uploaded by Jacek Pietruszewski
  2 Receptacles epaleate; leaves pinnatisect; [waif, ne. US]
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Show caption*© Scott Ward
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Show caption*© Dan Spaulding, some rights reserved (CC BY-NC), uploaded by Dan Spaulding
  2 Receptacles paleate; leaves simple or bladeless; [widespread natives]
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Show caption*© Dan Spaulding, some rights reserved (CC BY-NC), uploaded by Dan Spaulding
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Show caption*© Alan Cressler: Coreopsis nudata, Apalachicola National Forest, Franklin County, Florida 2 by Alan Cressler
    3 Leaves without blades (the petioles terete, appearing Juncus-like); ray florets pink or purplish; disc florets fewer (60-120+), the corollas usually yellowish; [wet pinelands and seepages]
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Show caption*© Scott Ward
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Show caption*© Keith Bradley
    3 Leaves broad and conspicuous; ray florets purple; disc florets many (200+), the corollas pink, green, red, purple, or yellow colored; [plants of prairies and similar habitats]
1 Rays primarily white to white-tinged or yellow throughout (lamina of the ray with at least some white basally if not uniformly yellow).
      4 Disc florets functionally staminate (thus cypselae only forming from ray florets)
      4 Disc florets bisexual, fertile.
        5 Leaves entire or toothed, but not deeply pinnatisect; sometimes with smaller rounded lobes (Leucanthemum basal leaves can have deeper, round lobes); plants usually not aromatic.
          6 Stem internodes usually winged (at least proximally)
          6 Stems not winged.
             7 Leaves primarily basal, the cauline leaves absent or fewer and much reduced in size from basal leaves; abaxial surface of the ray laminae white or sometimes pink-tinged (on live plants) but lacking a prominent colored midstripe.
               8 Leaves strigose, the margins crenate-serrate; roots not red-tipped; abaxial surface of ray laminae often pink or purple tinged, flowers closing at night
               8 Leaves glabrous (or faces sparsely hairy), the margins entire or toothed; roots usually red-tipped; rays drying pinkish but abaxial surface not conspicuously pink tinged on live plants
             7 Plants with well-developed cauline leaves, the margins entire or sometimes toothed (usually entire in Aphanostephus, occasionally deeply lobed); abaxial surface of the ray lamina sometimes white, but often with a prominent purple or blue midstripe (except Leucanthemum, which merely dries pink)
                 9 Flowering heads smaller, arranged in corymbiform or paniculiform arrays; ray florets with diminuitive laminae (0.3-5.0 mm long), heads thus sometimes superficially appearing disciform (rays sometimes double in horticultural forms as in Achillea ptarmica)
                   10 Plants aromatic; leaves linear to narrowly lanceolate, the surfaces glabrous or sparsely hairy; pales more or less folded but lacking distal papillae; cypselae not shed along with subtending phyllary and disc florets; [tribe Anthemideae]
                   10 Plants not aromatic; leaves variously shaped, at least some usually lyrate or oblanceolate (not all linear), the surfaces hairy and gland-dotted (at least abaxially); pales distally pappilate or fimbriate; cypselae shed along with subtending phyllary and 2 disc florets each invested in a pale; [tribe Heliantheae]
                 9 Flowering heads larger, singular on scapes (if in 2's or 3's, these large and not in broad corymbiform arrays), rays prominent, the laminae usually > 10 mm long
                     11 Rays white abaxially (drying pinkish); receptacles broadly convex, not pitted; plants rhizomatous perennials; pappus absent; [tribe Anthemideae]
                     11 Rays white or with prominent blue or purple midstripe (sometimes present after drying); receptacles conic, pitted; plants tap-rooted annuals (except Astranthium riddellii); pappus absent, coroniform, or of scales; [tribe Astereae]
                       12 Phyllaries scarious margined; cypselae 4-angled and with 4-12 thick ribs, pappus absent, of scales or coroniform; ray florets closing distally at night
                       12 Phyllaries sometimes hyaline but not scarious margined; cypselae compressed, lacking prominent ribs (though sometimes glochidiate), pappus absent or short coroniform; ray florets not closing at night
        5 Leaves deeply lobed or pinnatisect, the ultimate segments linear or if rounded, the sinuses of the lobes nearly reaching the midrib (pinnatifid); plants typically aromatic (except Tripleurospermum and Parthenium); [tribe Anthemideae].
                          13 Receptacles paleate (chaffy or with apparent bracts), the pales sometimes distally fimbriate or papillate (Parthenium).
                            14 Stem internodes usually winged
                            14 Stems not winged.
                              15 Rays (the laminae) white with conspicuous yellow coloration at the bases
                              15 Rays primarily white to white-tinged (without strong yellow color at the base of the laminae) or yellow throughout (lamina of the ray with at least some white basally; if rays are white).
                                16 Flowering heads smaller, arranged in corymbiform or paniculiform arrays; ray florets with diminuitive laminae (0.3-5.0 mm long); ray and disc florets both white or white-ish.
                                  17 Plants usually aromatic; pales more or less folded but not distally fimbriate or papillate; cypselae not shed along with phyllary and disc florets; [tribe Anthemideae]
                                  17 Plants not aromatic (at least not conspicuously so); pales distally fimbriate or papillate; cypselae shed along with subtending phyllary and 2 disc florets each invested in a pale; [tribe Heliantheae]
                                16 Flowering heads larger, arranged mostly singular at the ends of scapes, not in broad corymbiform arrays (except Tripleurospermum, which has larger heads and prominent rays), ray laminae prominent; ray and disc florets differing in color (rays typically white; discs typically yellow).
                                    18 Plants annual, erect or decumbent, ill-scented or not; ultimate leaf margins dentate to lobed; cypsela ribs usually 9-10 (sometimes lacking); [widespread non-natives]
                                    18 Plants perennial and prostrate (mat-forming), aromatic; ultimate leaf margins entire; cypsela ribs weak; [waif, ne. US]
                          13 Receptacles epaleate (lacking chaff).
                                       19 Ultimate leaf lobes broad, ovate-shaped (not linear)
                                       19 Ultimate leaf lobes linear.
                                         20 Plants usually aromatic; maturing flowering heads with deflexed ray laminae; cypsela 5-ribbed, lacking apical resin sacs
                                         20 Plants not aromatic; ray laminae not deflexed; cypsela with 3 ribs and 1-5 abaxial-apical resin sacs