2024 Edition • Get the App
X

Colors

Data mode

Account

Login
Sign up

X
Keyed in multiple places:

Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.

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

Copy permalink to share | Check for keys that lead to this key

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.
    3 Pappus of a minute crown (coroniform); disc florets white or whitish.
    3 Pappus absent, of 1-many scales, or of retrorsely barbed awns (or plumose bristles in Tridax procumbens); disk florets yellow, red-brown, or pinkish.
      4 Heads with an involucre not subtended by a calyculus.
        5 Rays pink, the laminae 5-14 mm long; [OK and TX westward]
        5 Rays white or whitish-yellow; the laminae typically < 5 mm long (occasionally longer in Polymnia); [collectively widespread]
          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]
          6 Plants smaller, 2-40 cm tall or long (if stems > 40 cm then plants usually procumbent); annuals or perennials; leaves usually < 10 cm long, lacking winged petioles or clasping basal appendages; disc florets bisexual and fertile; [non-natives of disturbed habitats].
             7 Plants with leaves simple, unlobed; pappus either absent or of fimbriate to aristate scales; plants annual, erect
             7 Plants usually with a mix of simple and 3-lobed leaves; pappus plumose; 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].
               8 Phyllaries connate for at least ¼ their length; heads with or without ray florets; [MS westwards in our area]
               8 Phyllaries distinct; heads with ray florets; [collectively widespread in our area].
                 9 Cypselas beaked, not strongly flattened, 7-30 mm long, with 1 groove per face; leaves highly dissected
                 9 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.
                   10 Cypselas 2.5-16 mm long, usually not winged; pappus awns (if present) usually retrorsely barbed; rays white
                   10 Cypselas 1.2-8 mm long, usually winged; pappus awns (if present) barbless or antrorsely barbed; rays pink, purple, or white
1 Rays predominantly yellow, orange, or red (sometimes with some brown, maroon, or purple coloration as well).
                     11 Receptacle naked, epaleate.
                       12 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].
                          13 Leaves unlobed, entire or serrate.
                            14 Leaves coarsely toothed, mostly opposite (the distal alternate)
                            14 Leaves entire (though with marginal setae), opposite
                          13 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).
                              15 Pinnate leaf segments lanceolate, 3-10 mm wide; calyculus absent
                              15 Pinnate leaf segments linear, 1-3 mm wide; calyculus present, of linear bracts and subtending the involucre.
                                16 Phyllaries distinct to their bases, or nearly so; ray florets 5-8; heads borne singly or in pairs/triplets; leaf surfaces puberulent
                                16 Phyllaries connate > ½ their length; ray florets 5-21; heads borne singly; leaf surfaces glabrous to variously pubescent/floccose
                       12 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.
                                  17 Leaf surfaces densely scabrous and canescent; [s. TX westward]
                                  17 Leaf surfaces glabrous to hirsute but never canescent; [collectively widespread]
                                    18 Leaves mainly basal or basally disposed (a few pairs low on the stem), the blades elliptic to ovate, the surfaces hirsute and stipate-glandular
                                    18 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
                                       19 Pappus absent or of 1-2 antrorsely-barbed or subplumose bristles; leaf blades usually lobed; [c. TX westward]
                                       19 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]
                                         20 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]
                                         20 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]
                     11 Receptacle paleate, with paleae, bristles, or scales.
image of plant
Show caption*© Scott Ward
                                           21 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).
image of plant
Show caption*© Swarochi Tathagath, some rights reserved (CC BY), uploaded by Swarochi Tathagath
                                             22 Inner phyllaries prickly with straight or uncinate prickles, and each enveloping a cypsela and swelling into a bur-like structure
                                             22 Inner phyllaries unarmed, not becoming bur-like (though those of Melampodium do invest the fruit).
                                               23 Plants with tack-glands or pit-glands on stems, leaves, and/or phyllaries; [waif, e. TX; native further westward]
                                               23 Plants without tack-glands or pit glands.
                                                 24 Outer phyllaries orbicular, connate 1/4 - 1/3 of their lengths; [exotic, rare]
                                                 24 Outer phyllaries orbicular to lance-linear, not connate; [native, collectively widespread in our area].
image of plant
Show caption*© Gary P. Fleming
                                                    25 Phyllaries in 2 series; pappus coroniform (Chrysogonum) or absent (Lindheimera)
                                                      26 Plants perennial, often trailing; pappus persistent, forming a minute, half-cup-shaped crown; [e. LA eastward, e. of MS river]
                                                      26 Plants annual, erect; pappus absent (cypselae with 2 pappus-like processes originating from cypsela wings); [w. LA westward, w. of MS river]
image of plant
Show caption*© Alan M. Cressler
                                                    25 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
                                                        27 Cypselae strongly flattened, borne in 2-3 series from the 2-3 series of ray florets
image of plant
Show caption*© Scott Ward
                                                        27 Cypselae thick, not flattened, borne in 1 series from the 1 series of ray florets
                                           21 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).
                                                          28 Ray corolla (the lamina) persistent on the achene and becoming papery and bleached.
                                                            29 Outer phyllaries with a stiff, maroon-colored subulate apex
                                                            29 Outer phyllaries lacking a stiff subulate apex.
                                                              30 Leaf margins serrate or toothed; plant a perennial; cypselae subterete, 4-5 mm long; [natives]
                                                              30 Leaf margins entire; plant an annual; cypselae 3-angled or flattened, 6-10 mm long; [non-native waifs]
                                                          28 Ray corolla articulate from the achene and falling after flowering.
                                                                 31 Pappus of 20 plumose bristles 4-5 (-7.5) mm long
                                                                 31 Pappus absent or of scales or awns (if with awnlike bristles as in Acmella, then these never plumose).
                                                                   32 Plants with tack-glands or pit-glands on stems, leaves, and/or phyllaries; [waif, VA and NC northward; subtribe Madiinae]
                                                                   32 Plants without tack-glands or pit-glands on stems, leaves, and/or phyllaries; [natives and non-natives, collectively widespread]
                                                                     33 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).
                                                                       34 Pappus absent; ray laminae longer, 8-14 mm long
                                                                       34 Pappus persistent, of 2-3(-5) scales or awns; ray laminae shorter, 2-5 mm long
                                                                         35 Cypselae all alike, sharp-edged but not winged
                                                                         35 Cypselae dimorphic, those of the ray florets with lacerate wings
                                                                     33 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.
                                                                           36 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
                                                                           36 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)
                                                                              37 Paleae completely surrounding the cypselae of the disc florets, forming a perigynium or sac-like appendage
                                                                              37 Paleae conduplicate or partially enclosing the cypselae, but not forming a sac-like appendage.
                                                                                38 Disc florets with hairy staminal filaments; pappus of 4-6 aristate to lacerate scales; [TX westward]
                                                                                38 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].
                                                                                  39 Rays primarily orange; [waif of FL, AL, and LA]
                                                                                  39 Rays primarily yellow; [natives and non-natives, collectively widespread]
                                                                                    40 Cypselae (of at least the disc florets) strongly flattened and generally also winged (thin-margined in Simsia).
                                                                                      41 Cypselae 1-2.5 mm (Acmella) or 3.5-6 mm long (Simsia); plants erect, decumbent, or prostrate; stems never winged.
                                                                                        42 Phyllaries 8-15; cypselae 1-2.5 mm long; involucre ca. 3-6 mm in diameter
                                                                                        42 Phyllaries 13-43; cypselae 3.5-6 mm long; involucre 5-16+ mm in diameter
                                                                                    40 Cypselae subterete, quadrangular, variously angled, or diamond-shaped in ×-section, not winged.
                                                                                           43 Ray florets pistillate (“fertile”).
                                                                                             44 Erect herb; leaves entire or with a few teeth; peduncles < 3 cm long
                                                                                             44 Creeping herb; leaves serrate and also mostly 3-lobed; peduncles 3-10 cm long
                                                                                           43 Ray florets completely neuter.
                                                                                               45 {XXXX}; Leaf surfaces and ray laminae abaxially gland-dotted; [SC waif; native to sw. US]
                                                                                               45 {YYYY}: CHECK FLORA TRANS-PECOS REGION
                                                                                                 46 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]
                                                                                                 46 Leaves linear, 0.5-7 mm wide; plants from slender horizontal tubers; [c. FL north to s. AL]

Key to Asteraceae, Key I: Herbaceous composites with the leaves alternate, the heads lacking rays, and with a pappus wholly or partly of scales or awns

Copy permalink to share | Check for keys that lead to this key

1 Disc flowers yellow, orange, red, or brownish.
  2 Leaves 1-2× pinnately lobed into linear or filiform segments.
    3 Pappus of 16-20 scales
    3 Pappus of 6-10 scales; [historical waif]
  2 Leaves unlobed, or if pinnately lobed, the segments broad (> 3 mm wide).
      4 Receptacle epaleate.
        5 Pappus scales rudimentary, crown-like
        5 Pappus scales conspicuous.
          6 Phyllaries 25-125 in 3-9 series; receptacles flat or slightly convex
          6 Phyllaries 6-25 (-60) in 2-3 series; receptacles globose.
             7 Stems not winged
             7 Stems winged from node to node
1 Disc flowers pink, purple, or white
               8 Receptacle paleate
               8 Receptacle epaleate.
                 9 Disc flowers 1-5 (rarely more) per head.
                   10 Disc flowers white (rarely cream), 3; heads not aggregated into a secondary cluster subtended by bracts; [se. TX]
                   10 Disc flowers lavender to purple, sometimes so lightly so as to be white, 1-4 (-5+); heads aggregated into clusters of 1-40 heads, subtended by 1-3 bracts; [collectively widespread in our region]
                     11 Heads (1-) 10-40 per secondary cluster, borne in corymbiform arrays; bracts subtending clusters (2-) 3, deltate; pappus of 5 (-6) scales, each aristate
                     11 Heads 1-5+ per secondary cluster, borne in spiciform arrays; bracts subtending clusters 1-2, linear, lanceolate, or spatulate; pappus of 6-10 scales, laciniate or aristate
                 9 Disc flowers (2-) 10-100+ per head (at least most heads with >10 flowers).
                       12 Phyllaries 5-15 (-21) in 1-2 (-3) series.
                          13 Involucres 2-3 mm in diameter; flowers 7-10 per head; [Coastal Plain, FL and GA]
                          13 Involucres 4-15+ mm in diameter; flowers 20-80 per head; [SC, GA, and FL westwards]
                       12 Phyllaries 18-many in 5+ series.
                            14 Phyllary tips modified into a spine or into an enlarged, lacerate or pectinate network or fringe; receptacle epaleate, but densely bristly; [tribe Cynareae].
                              15 Heads discoid, all flowers similar
                                16 Pappus normally of plumose bristles (and keyed elsewhere), but sometimes reduced to scales or awns
                                16 Pappus of an outer setiform scales (appearing as "flattened bristles"
                              15 Heads disciform or radiant, the outer flowers of the head sterile, with long lobes, appearing like false rays
                                  17 Plant a perennial; flowers pink to purple, flowering Jun-Oct
                                  17 Plant an annual; flowers pale to medium blue, flowering Apr-Jun
                            14 Phyllary tips not so modified, unarmed and unelaborate; receptacle epaleate and naked; [tribe Vernonieae].
                                    18 Peripheral flowers of the heads enlarged and bilaterally symmetrical, appearing like "false rays"
                                    18 Peripheral flowers of the heads similar to the interior flowers, all disc flowers.
                                       19 Annuals; cypselas not ribbed
                                       19 Perennials; cypselas 8-10-ribbed.
image of plant
Show caption*© Jacek Pietruszewski, some rights reserved (CC BY), uploaded by Jacek Pietruszewski
                                         20 Heads each subtended by 3-8 leafy bracts; pappus of narrow scales only, quickly falling
                                         20 Heads not subtended by leafy bracts; pappus of an inner series of scales or bristles and an outer series of bristles, persistent

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

Copy permalink to share | Check for keys that lead to this key

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].
                   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

Copy permalink to share | Check for keys that lead to this key

1 Rays primarily pink or purple, not white-tinged (flowers viewed from above, adaxial surface of the rays).
  2 Receptacles epaleate; leaves pinnatisect; [waif, ne. US]
  2 Receptacles paleate; leaves simple or bladeless; [widespread natives]
    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]
    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

Key to Asteraceae, Key N: Herbaceous composites with the leaves alternate or basal and the heads radiate, the rays white, pink, purple, and the pappus absent or essentially so

Copy permalink to share | Check for keys that lead to this key

1 Receptacles paleate (with chaff); [tribe Heliantheae].
  2 Stems not winged; leaves simple; disc florets and ray florets differing in color
  2 Stems usually winged; leaves simple or pinnately to palmately lobed; disc florets concolorous (of similar color) with ray florets
1 Receptacles epaleate (lacking chaff).
    3 Leaves 1-3 pinnately-lobed or pinnatifid.
      4 Plants arachnose or wooly pubescent throughout; [waif, SC; tribe Arctotideae]
      4 Plants glabrous or densely viscid but not wooly tomentose throughout (if hirsuto-pilose, this usually concentrated distally).
        5 Receptacles flat or broadly conic, not conspicuously pitted; heads in corymbiform arrays; pappus a short crown; rays white, pink, or purple adaxially; [widespread non-natives, tribe Anthemideae]
        5 Receptacles conic, pitted; heads borne singly (Aphanostephus) or in loose corymbiform arrays (Egletes); rays white adaxially; [natives primarily w. of MS river; tribe Astereae].
          6 Plants aromatic, but not densely viscid, instead sometimes hairy distally; ray laminae not shorter than involucre; phyllary margins broadly scarious; pappus coroniform or a mix of variously shaped scales; [widespread w. of MS river]
          6 Plants densely viscid with stipitate-glandular trichomes; ray laminae sometimes shorter than involucre; phyllary margins scarious or not; pappus of uneven rings; [TX]
    3 Leaves entire or toothed, but neither deeply lobed nor pinnatifid.
             7 Plants 1-3 cm tall, densely pin-cushioned (pulvinate); flowering heads sessile, borne singly, conspicuously nestled within the rosette leaves and proportionately of similar size; pappus persistent, of 12-35+ setiform scales in 1 series; phyllaries in 4-6+ series
             7 Plants of various size, but not densely pin-cushioned; flowering heads borne on stems, if peduncles short the heads not conspicuously nestled within similar-sized leaf rosettes; pappus various, phyllaries in 2-6 series.
               8 Pappus of 5-40+ longer inner bristles plus shorter outer scales or setae (these sometimes falling); stems and leaves often (but not always) stipitate-glandular.
                 9 Inner barbellate bristles numerous (5-40+); stems and leaves usually glandular; plants tap-rooted, fibrous-rooted, or stoloniferous; annuals, biennials, or perennials
                 9 Inner bristles barbellate or thicker, fewer (ca. 5); stems and leaves glandular (C. asteroides) or eglandular (C. asteroides; C. belliloides); plants tap-rooted annuals
               8 Pappus primarily of awns, scales, crowns, or thickened rings (these minute, 0.1-0.8 mm long), sometimes also accompanied by shorter inner scales or bristles; stems and leaves eglandular (sometimes minutely glandular in Chaetopappa bellidifolia).
                   10 Cypsela margins narrowly winged or winglike.
                     11 Receptacles obscurely pitted; pappus of 2-3 sclerified awns plus often with 7-12 shorter bristles or scales; [collectively widespread]
                     11 Receptacles smooth; pappus of 2 thin awns plus an elliptic ring of shorter awns; [s. TX]
                   10 Cypsela margins not narrowly winged (4-angled in Aphanostephus but lacking marginal wings).
                       12 Receptacles conic, pitted; cypselae 4-angled; pappus of setiform to awn-tipped scales or short ciliate crowns (0.1-0.2 mm long, minute, thus requiring magnification)
                       12 Receptacles flat or slightly convex, smooth (not pitted); cypselae variously shaped but not conspicuously 4-angled; pappus of minute, thickened rings (C. bellidifolia) or erose cuplike crowns (C. imberbis)

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

Copy permalink to share | Check for keys that lead to this key

1 Receptacles chaffy (paleate).
  2 Phyllaries dry, scarious-margined.
    3 Ray florets 1-5 mm long; heads small in corymbiform arrays
    3 Ray florets > 5 mm long; heads large, terminating the branches
  2 Phyllaries herbaceous, not scarious on margins.
      4 Ray florets < 2.5 mm long; disk florets sterile, with an undivided style
      4 Ray florets > 5 mm long; disk florets fertile, with a divided style.
        5 Ray florets pink or light purple, > 15 mm long; heads single
        5 Ray florets white, 5-10 mm long; heads 20-100 in a compound corymb
1 Receptacles naked (epaleate).
          6 Pappus absent or coroniform.
             7 Achene faces minutely glandular-glochidiate (bearing small gland-like bristles)
             7 Achene faces glabrous or short-strigose but not glandular-glochidiate.
               8 Leaves basal; cypselae marginally 2-ribbed; mature plants < 2 dm tall
               8 Leaves cauline (and sometimes also basal); cypselae with ± 10 ribs; mature plants > 2 dm tall
                 9 Heads solitary or 2-3 in corymbiform arrays
                 9 Heads 5-60+ in corymbiform arrays
          6 Pappus present, of bristles or scales.
                   10 Heads primarily discoid with reduced ray florets
                   10 Heads radiate with conspicuous ray florets.
                     11 Taprooted annuals; ray florets 1-7 mm long.
                       12 Leaves and stems not fleshy, rarely glabrous; cypselas < 1.4 mm long
                       12 Leaves and stems fleshy, mostly glabrous; cypselas > 1.4 mm long
                     11 Not taprooted and mostly perennials; ray florets > 3 mm long.
                          13 Ray florets usually > 60; blooming Apr-Oct
                          13 Ray florets usually < 60; blooming late May-Nov.
                            14 Receptacles hemispheric to conic; pappus often with 2-4 awns (Boltonia) or lacking awns and coroniform (Astranthium).
                              15 Achenes not narrowly winged, the surfaces minutely glandular-glochidiate (bearing small gland-like bristles)
                              15 Achenes narrowly winged, the surfaces sometimes puberulent but not glandular-glochidiate
                            14 Receptacles flat to slightly convex; pappus lacking awns.
                                16 At least the basal and lower leaves both petiolate and cordate/subcordate at base.
                                  17 Often colonial; inflorescence corymbiform, flat-topped or rounded; outer phyllaries > 1 mm broad
                                  17 Not colonial; inflorescence paniculiform, often elongate; outer phyllaries < 1 mm broad
                                16 Basal and lower leaves not both petiolate and cordate/subcordate at base.
                                    18 Leaves sessile and auriculate or cordate-clasping
                                    18 Leaves petiolate or epetiolate but not auriculate or cordate-clasping.
                                       19 Cypselas glandular; pappus double
                                       19 Cypselas not glandular; pappus single or double or in four series.
                                         20 Leaves silvery-silky on both sides (at least when young), entire
                                         20 Leaves not silvery-silky, entire or toothed.
                                           21 Pappus double, with inner bristles distinctly longer than outer bristles.
                                             22 Leaves not rigid, veiny, lanceolate to elliptic or ovate, > 6 mm wide
                                             22 Leaves rigid, 1-nerved, linear to linear-spatulate, < 5 mm wide
                                           21 Pappus simple with all bristles often about the same length.
                                               23 Ray florets white, few (usually 3-8); cypselas densely silky
                                               23 Ray florets white to pink or blue or purple, more numerous (usually 8-30); cypselas glabrous to pubescent but not densely silky.
                                                 24 Ray florets white; involucres < 6 mm long; phyllaries < 1 mm wide
                                                 24 Ray florets white or pink to blue or purple; involucres 7-12 mm long; phyllaries usually > 1 mm wide.
image of plant
Show caption*© Scott Ward
                                                    25 Phyllaries glandular
                                                    25 Phyllaries not glandular.
                                                      26 Phyllaries long-attenuate or loose and spreading
                                                      26 Phyllaries appressed, not long-attenuate.
                                                        27 Plants coarse-hairy; lowest leaves > 5 cm wide
                                                        27 Plants glabrous to hairy; lowest leaves < 3 cm wide
Cite as...