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Key to Asteraceae

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1 Plant a shrub or liana (woody vine), definitely with woody growth well above ground level
1 Plant an annual, biennial, or perennial, lacking woody growth above ground level.
..2 Leaves opposite or whorled, at least on the lower stem nodes (the leaves higher on the stem sometimes alternate).
..2 Leaves either alternate (not opposite even at lower nodes of the stem) or basal only (the heads on scapiform stems).
......4 Heads discoid, disciform, radiant, or radiate; sap usually clear.
........5 Heads discoid, disciform, or radiant.
image of plant
Show caption*© Gary P. Fleming
..........6 Leaves spiny-margined, phyllaries usually spine-tipped; disk flowers pink (rarely blue or yellow)
..........6 Leaves not spiny-margined; phyllaries spine-tipped or not; disk flowers variously colored (including pink)

Key to Asteraceae, Key A: woody composites (shrubs and lianas)

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1 Leaves strictly alternate; [tribe Astereae].
..2 Heads discoid; dioecious shrubs to 5 m tall; [widespread in our area]
..2 Heads radiate (most or all on a plant); bisexual shrub to 1 m tall or scrambling liana; [of se. NC southward, native in the Coastal Plain only].
....3 Leaves with clasping base, with a midvein and lateral veins and tertiary reticulation; rays pink or rose; sprawling viny shrub to 4 m tall; [of wet habitats of SC (or se. NC) southward, also cultivated]
....3 Leaves with a cuneate base, with a midvein and otherwise minutely pebbled; rays yellow; intricately branched shrub to 1 m tall, with persistent sterile shoots with evergreen leaves and annual flowering shoots (the entire shoot and leaves deciduous); [of xeric sandy barrens, of se. NC southward]
1 Leaves opposite, at least on the lower stem nodes (the leaves higher on the stem sometimes alternate); [tribe Heliantheae].
......4 Heads radiate, ray florets yellow; disc florets yellow; leaves strictly opposite or in part alternate.
........5 Leaves obovate to oblanceolate, unlobed; leaves strictly opposite; [of tidally inundated salt and brackish marshes of the outer Coastal Plain ]; [tribe Heliantheae; subtribe Ecliptinae]
........5 Leaves rhombic or pentagonal, unlobed or more often 3-5-lobed; leaves in part alternate; [of disturbed, suburban areas of FL peninsula]; [tribe Heliantheae; subtribe Helianthinae]
......4 Heads discoid or disciform, ray florets lacking; disc florets pink, purple, or whitish; leaves opposite, but usually at least in part alternate higher on the stem; [collectively of various habitats, Coastal Plain and inland].
..........6 Heads solitary, axillary in the axils of leaves or leafy bracts; heads nodding, the involucre 2-7 mm high; [collectively widespread in our area, of maritime and inland wetlands or moist disturbed areas]; [tribe Heliantheae; subtribe Ambrosiinae]
 Iva
..........6 Heads many, terminal on the branches of corymbiform arrays; heads erect, the involucre 4-12 mm high; [of Coastal Plain of FL, s. GA, s. AL, and c. MS, of dry, sandy scrub and pinelands, blackland prairies, or dry, disturbed areas].
............ 7 Leaves with punctate glands; pappus of 60-70 barbellate bristles, 8-12 mm long; [tribe Heliantheae; subtribe Eupatoriae]
............ 7 Leaves lacking punctuate glands; pappus of 4-10 scales, 0.3-7 mm long; [tribe Heliantheae; subtribe Chaenactidinae]

Key to Asteraceae, Key B: herbaceous composites with opposite or whorled leaves
and discoid or disciform heads (lacking ray florets)

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1 Pappus present, of 5-60 barbellate bristles; receptable naked (without paleae or well-developed bristles); [tribe Heliantheae; subtribe Eupatoriae].
..2 Plant a twining herb, phyllaries and disk florets 4 per head
..2 Plant stiffly erect to weakly spreading but never twining, phyllaries and disk florets usually > 4 per head.
....3 Leaves in whorls of 3-7, > 2 cm wide
....3 Leaves opposite, rarely alternate or whorled, if whorled, < 2 cm wide.
......4 Achenes (and ovaries) 8-10-ribbed; outer phyllaries longitudinally striate
......4 Achenes (and ovaries) (3-) 4-5-ribbed; outer phyllaries not noticeably longitudinally striate.
........5 Heads pink to blue.
..........6 Phyllaries in 4-6+ series, deciduous
..........6 Phyllaries in 2-4 series, persistent (or deciduous in Praxelis).
............ 7 Heads pink (rarely bluish); receptacles flat; florets 18-25 per head
............ 7 Heads blue; receptacles conic; florets 25-70 per head.
............ ..8 Bristles ca. 40; florets 25-30; phyllaries 15-25, unequal, deciduous (absence apparent in fruit)
............ ..8 Bristles ca. 30; florets 35-70+; phyllaries ca. 25, subequal, persistent
........5 Heads white to cream or, rarely, pale lilac.
............ ....9 Florets 3-7 per head
............ ....9 Florets at least 9 per head.
............ ......10 Phyllaries not strongly imbricate, with the principal ones subequal and sub-biseriate; petioles 0.5-10 cm
............ ......10 Phyllaries clearly imbricate, in 3+ series; some species epetiolate
1 Pappus absent, or of scales, setae, or awns; receptacle either naked, or with paleae or well-developed bristles.
............ ........11 Leaves whorled, linear, < 2 mm wide; head solitary; [aquatic herb growing in shallow stagnant water]
............ ........11 Leaves opposite (or alternate in part), broader in shape and > 5 mm wide; heads typically not solitary; [terrestrial or wetland plants].
............ ..........12 Receptacle naked.
............ ............ 13 Pappus of 4-10 scales; heads white, pink, or blue.
............ ............ ..14 Heads with 20-125 florets; leaves serrate; [rarely naturalized aliens in our area]
............ ............ ..14 Heads with 10-30 florets; leaves entire; [natives, of FL, s. GA, and MS in our area]
............ ............ 13 Pappus none, or of a few bristles or irregular coroniform lobes; heads green to yellow.
............ ............ ....15 Heads bright yellow, closely aggregated into corymbiform arrays of flat-topped to dome-shaped glomerules
............ ............ ....15 Heads greenish or greenish yellow, borne in spiciform, racemiform, or paniculiform arrays.
............ ............ ......16 Heads in paniculiform arrays, all or most of the heads not subtended by bracts
............ ............ ......16 Heads in spiciform or racemiform arrays, each 1 (-2) heads subtended by a bract
 Iva
............ ..........12 Receptable with paleae or well-developed bristles.
............ ............ ........17 Heads small, less than 1 cm in diameter at anthesis (the female heads enlarging in Xanthium); disc florets dull white or suffused with green or purple; florets mainly unisexual (either in the same heads and then males central and females peripheral, or in separate female and male heads); female florets 0-8 per head; [tribe Heliantheae; subtribe Ambrosiinae]
............ ............ ..........18 Heads unisexual; cypselas shed within an indurated bur or “nut” with hooked or straight spines developed from the phyllaries and/or paleae.
............ ............ ............ 19 Involucre of the female heads with tubercles or straight spines developing from the phyllaries; burs 1-8 mm long
............ ............ ............ 19 Involucre of the female heads with hooked spines developing from the phyllaries/paleae; burs 10-35 mm long
............ ............ ..........18 Heads bisexual, with functionally male and female flowers in the same head; cypselas shed individually, not enclosed.
............ ............ ............ ..20 Heads in paniculiform arrays, all or most of the heads not subtended by bracts
............ ............ ............ ..20 Heads in spiciform or racemiform arrays, each 1 (-2) heads subtended by a bract
 Iva
............ ............ ........17 Heads larger, mostly > 1 cm in diameter at anthesis; disc florets conspicuously white, yellow, pale yellow, or purple; florets mainly bisexual; female florets > 12 per head (except 2-8 in Polymnia).
............ ............ ............ ....21 Disc flowers maroon-purple; leaves mainly basal
............ ............ ............ ....21 Disc flowers white, pale yellow, or bright yellow; leaves mainly or strictly cauline.
............ ............ ............ ........23 Involucre of phyllaries not subtended by a calyculus
............ ............ ............ ........23 Involucre of phyllaries subtended by a calyculus of bracts obviously different in color, texture, and shape than the phyllaries
............ ............ ............ ......22 Disc flowers bright white or pale yellow.
............ ............ ............ ..........24 Disc flowers bright white; leaves unlobed or with 2 basal lobes
............ ............ ............ ..........24 Disc flowers creamy or pale yellow; leaves prominently pinnately lobed, with 5-many lobes

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

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1 Involucre of phyllaries subtended by a calyculus of bracts obviously different in color, texture, and shape than the phyllaries; [tribe Heliantheae; subtribe Coreopsidinae].
..2 Phyllaries connate for at least ¼ their length; [MS westwards in our area]
..2 Phyllaries distinct; [collectively widespread in our area].
....3 Cypselas beaked, not strongly flattened, 7-30 mm long, with 1 groove per face; leaves highly dissected
....3 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.
......4 Cypselas 2.5-16 mm long, usually not winged; pappus awns (if present) usually retrorsely barbed
......4 Cypselas 1.2-8 mm long, usually winged; pappus awns (if present) barbless or antrorsely barbed
1 Involucre of phyllaries not subtended by a calyculus (or subtended by a calyculus of narrowly linear segments bearing oil glands in Dyssodia and Thymophylla).
........5 Ray florets white, pink, or purple (rarely pale yellow or lavender).
..........6 Ray flower persistent on the achene and becoming papery and bleached.
..........6 Ray flower articulate from the achene and falling.
............ 7 Pappus of a minute crown; disk florets white or whitish
............ 7 Pappus either lacking, or of numerous scales, or of retrorsely barbed awns; disk florets yellow.
............ ..8 Annual of disturbed habitats; leaves usually < 1 dm long; phyllaries < 5 mm long
............ ..8 Perennial of native habitats; leaves > 1 dm long; phyllaries > 6 mm long
........5 Rays predominantly yellow, orange, or red (sometimes with some brown, maroon, or purple coloration as well).
............ ....9 Receptacle naked, epaleate.
............ ......10 Leaves and phyllaries with large, scattered, embedded oil glands, translucent in living plants, usually golden-brown or blackish in herbarium specimens), making the plants strongly aromatic; annual plants, decumbent and much branched from the base (except Tagetes, annual and generally erect and sparingly branched); [tribe Heliantheae; subtribe Pectidinae].
............ ........11 Leaves unlobed, entire (though with marginal setae)
............ ........11 Leaves pinnately lobed, the margins also often serrate.
............ ..........12 Pinnate leaf segments lanceolate, 3-10 mm wide; calyculus absent
............ ..........12 Pinnate leaf segments linear, 1-3 mm wide; calyculus present, subtending the involucre, of linear bracts.
............ ............ 13 Phyllaries distinct to their bases, or nearly so
............ ............ 13 Phyllaries connate > ½ their length
............ ......10 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.
............ ............ ..14 Phyllaries 6 (-9), in 1 series; disc florets 1-15
............ ............ ..14 Phyllaries 12-26, in 2-3 series; disc florets 20-150.
............ ............ ....15 Pappus of 5-6 aristate scales; [exotic, rare waif in our area]
............ ............ ....15 Pappus of barbellate bristles (or absent); [native, collectively fairly widespread in our area].
image of plant
Show caption*© Scott Ward
............ ............ ......16 Phyllaries 12-18; rays usually 8-16; leaves mainly basal or basally disposed (a few pairs low on the stem); [on various, usually acid substrates, in the Coastal Plain and Piedmont from NJ and PA south to n. and Panhandle FL]
image of plant
Show caption*© Scott Ward
............ ............ ......16 Phyllaries broadly ovate, squarrose, in several imbricate series; rays usually 8; leaves cauline; [on calcareous substrates in n. AL]
............ ....9 Receptacle paleate, with paleae, bristles, or scales.
image of plant
Show caption*© Scott Ward
............ ............ ........17 Disk florets functionally staminate (“sterile”, not producing cypselas), the style undivided, their ovaries much smaller than those of the ray flowers (which are functionally pistillate).
image of plant
Show caption*© Swarochi Tathagath, some rights reserved (CC BY), uploaded by Swarochi Tathagath
............ ............ ..........18 Inner phyllaries prickly with straight or uncinate prickles, and each enveloping a cypsela and swelling into a bur-like structure
............ ............ ..........18 Inner phyllaries unarmed, not becoming bur-like (though those of Melampodium do invest the fruit).
............ ............ ............ 19 Outer phyllaries orbicular, connate 1/4 - 1/3 of their lengths; [alien, rare]
............ ............ ............ 19 Outer phyllaries orbicular to narrower, not connate; [native, collectively widespread in our area].
image of plant
Show caption*© Gary P. Fleming
............ ............ ............ ..20 Slender, small plants, the stems to 5 dm long, often trailing; pappus persistent, forming a crown
image of plant
Show caption*© Alan M. Cressler
............ ............ ............ ..20 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
............ ............ ............ ....21 Cypselas strongly flattened, borne in 2-3 series from the 2-3 series of ray florets
image of plant
Show caption*© Scott Ward
............ ............ ............ ....21 Cypselas thick, not flattened, borne in 1 series from the 1 series of ray florets
............ ............ ........17 Disk florets functionally bisexual (“fertile”, producing cypselas), the style divided, their ovaries as large as, or larger than, those of the ray florets (which may be either functionally pistillate or completely neuter).
............ ............ ............ ......22 Ray corolla persistent on the achene and becoming papery and bleached.
............ ............ ............ ........23 Plant a perennial; cypselas subterete, 4-5 mm long
............ ............ ............ ........23 Plant an annual; cypselas 3-angled or flattened, 6-10 mm long
............ ............ ............ ......22 Ray corolla articulate from the achene and falling after flowering.
............ ............ ............ ..........24 Pappus of 20 plumose bristles 4-5 (-7.5) mm long
............ ............ ............ ..........24 Pappus various, but not as above.
............ ............ ............ ............ 25 Paleae flattened, not notably clasping the cypsela; cypsela usually notably flattened in the same plane as the phyllaries and the paleae, i.e. at a right angle to the radii of the head; heads small, the receptacle 3-8 mm in diameter.
............ ............ ............ ............ ..26 Cypselas dimorphic, those of the ray florets with lacerate wings
............ ............ ............ ............ 25 Paleae conduplicate (V-shaped in cross section), the 2 sides of the V partially clasping the cypsela; cypsela either subterete, multi-angled in ×-section, or flattened parallel to the radii of the head; heads mostly larger.
............ ............ ............ ............ ....27 Phyllaries apparently 4 (the 4 outer foliaceous phyllaries forming a quadrangle which hides the much smaller and narrower inner phyllaries)
............ ............ ............ ............ ....27 Phyllaries not as above (5 or more phyllaries readily visible).
............ ............ ............ ............ ......28 Cypselas (of at least the disk florets) strongly flattened and generally also winged.
............ ............ ............ ............ ........29 Cypselas 1-2.5 mm long; herb to 2 dm tall (erect or creeping)
............ ............ ............ ............ ........29 Cypselas 3-7 mm long; herb to 1-40 dm tall (erect)
............ ............ ............ ............ ......28 Cypselas subterete, quadrangular, variously angled, or diamond-shaped in ×-section, not winged.
............ ............ ............ ............ ............ 31 Erect herb; leaves entire or with a few teeth; peduncles < 3 cm long
............ ............ ............ ............ ............ 31 Creeping herb; leaves serrate and also mostly 3-lobed; peduncles 3-10 cm long
............ ............ ............ ............ ............ ..32 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]
............ ............ ............ ............ ............ ..32 Leaves linear, 0.5-7 mm wide; plants from slender horizontal tubers; [of Coastal Plain of FL and s. AL]

Key to Asteraceae, Key D: herbaceous composites with leaves alternate or basal,
liguliflorous heads (composed of ligulate florets), and sap usually milky

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1 Cypselas (at least of the inner florets of the head) beaked.
..2 Heads solitary and terminal at the end of a stem unbranched to its base.
....3 Leaves basal and cauline, grasslike (untoothed and unlobed); stem leafy
....3 Leaves basal only, variously toothed to pinnately lobed; stem scapiform (leafless).
......4 Pappus of bristles
......4 Pappus either of outer scales and inner bristles or entirely of aristate scales.
........5 Pappus of outer scales and inner plumose bristles; leaves oblanceolate to oblong; plants annual or perennial
........5 Pappus of aristate scales; leaves linear to narrowly lanceolate; plants annual
..2 Heads several per stem, in various corymbiform, umbelliform, spiciform, or paniculiform arrays (rarely solitary and terminal in the smallest and most depauperate individuals in a population.
..........6 Achenes distinctly flattened
..........6 Achenes terete or prismatic.
............ 7 Pappus of plumose bristles, at least the inner series; plant an annual or biennial.
............ ..8 Receptacles lacking paleae
............ ..8 Receptacles with paleae
............ 7 Pappus of simple capillary bristles; plant an annual, biennial, or perennial.
............ ....9 Beak of the cypsela with a ring of soft white reflexed hairs at the summit (just below the pappus)
............ ....9 Beak of the cypsela lacking a ring of hairs as described.
............ ......10 Pappus of 80-150 barbellulate bristles; plant an annual or biennial
............ ......10 Pappus either of 40-50 (or more) smooth bristles or of 20-30 barbellulate bristles; plant a perennial
............ ........11 Pappus of 40-50 (or more) smooth bristles
............ ........11 Pappus of 20-30 barbellulate bristles
1 Cypselas beakless.
............ ..........12 Leaves basally disposed (stem leaves few or none, if present generally smaller in size than the basal leaves, which are persistent into flowering and fruiting); corollas yellow, orange, or red.
............ ............ 13 Pappus absent or of both scales and barbellulate bristles
............ ............ 13 Pappus of bristles only (these barbellulate or plumose).
............ ............ ..14 Pappus of plumose bristles (these somewhat flattened at their bases)
............ ............ ..14 Pappus of barbellulate bristles.
............ ............ ....15 Leaves with entire margins; plants perennials, either from long to short rhizomes or from a short caudex with fibrous roots
............ ............ ....15 Leaves coarsely toothed or pinnately lobed; plants annuals, from a taproot.
............ ............ ......16 Involucre 5-12 mm high; achenes usually > 2.5 mm long; pappus bristles distinct, 3-7 mm long
............ ............ ......16 Involucre 3-5 mm high; achenes 1.5-2.5 mm long; pappus bristles basally connate, 2.5-3.5 mm long
............ ..........12 Leaves basal and cauline (plant often beginning with a basal rosette, but by flowering bearing well-developed stem leaves about as large as the basal leaves, the basal rosette often withering prior to flowering and fruiting); corollas yellow, orange, red, blue, pink, white, or lavender.
............ ............ ........17 Pappus absent or of scales.
............ ............ ..........18 Corollas pale blue (rarely pink or white)
............ ............ ..........18 Corollas yellow (rarely orange).
............ ............ ............ 19 Phyllaries enfolding the outer cypselas
............ ............ ............ 19 Phyllaries not enfolding the outer cypselas.
............ ............ ............ ..20 Stem winged and spiny; leaves spiny-margined; receptacle with paleae
............ ............ ............ ..20 Stem not winged or spiny; leaves not spiny-margined; receptable lacking paleae.
............ ............ ............ ....21 Cypselas 1.2-2.8 mm long; heads borne single at the ends of scapiform stems that are unbranched (rarely few-branched near the base); plants to 7 dm tall
............ ............ ............ ....21 Cypselas 3-5 mm long; heads borne in corymbiform or thyrsiform arrays; plants to 15 dm tall
............ ............ ........17 Pappus of numerous smooth, barbellate, or plumose bristles.
............ ............ ............ ......22 Cypselas more or less strongly flattened.
............ ............ ............ ........23 Pappus of 30-45+ bristles, these at least partly plumose
............ ............ ............ ........23 Pappus of simple capillary bristles only
............ ............ ............ ......22 Cypselas terete or prismatic, slightly or not at all flattened.
............ ............ ............ ..........24 Corollas pink, purple, lavender, white, or creamy-yellow.
............ ............ ............ ............ 25 Leaves linear, entire, < 3 mm wide, or reduced to scales; cypselas 11-14 mm long; [of the Coastal Plain of GA and se. AL south to s. FL]
............ ............ ............ ............ 25 Leaves broader, of various shapes, usually hastate, irregularly lobed, and/or serrate; cypselas 3.5-10 mm long; [collectively widespread in our area, south to n. FL]
............ ............ ............ ..........24 Corollas bright yellow, orange, or red.
............ ............ ............ ............ ..26 Plants taprooted annuals and biennials (rarely perennials); pappus bristles white and soft in texture
............ ............ ............ ............ ..26 Plants fibrous-rooted perennials; pappus bristles white, light to medium tan, or sordid, stiff.
............ ............ ............ ............ ....27 Cypselas (2-) 2.5-7 mm long; pappus of (30-) 40-80 white, tan, or sordid bristles, in 1-2+ series; plants cespitose; corollas yellow
............ ............ ............ ............ ....27 Cypselas 1-2.5 mm long; pappus of 25-40+ white to sordid bristles, in 1 series; plants stoloniferous (cespitose in a few species); corollas yellow or orange

Key to Asteraceae, Key E: herbaceous composites with leaves spiny, leaves alternate or basal, and heads discoid

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1 Heads appearing spherical (the ‘visual head’ actually a secondary head aggregated of numerous 1-flowered heads); disk flowers blue (rarely almost white)
1 Heads not spherical; disk flowers pink (rarely yellow).
..2 Stem winged, the wings armed with spines.
....3 Pappus of plumose bristles
....3 Pappus of barbellulate bristles.
......4 Cypselas borne on the surface of the receptacle, intermixed with setiform scales; foliage glabrous or more loosely and sparsely pubescent
......4 Cypselas borne in the pits of the naked honeycombed receptacle; foliage densely white-tomentose
..2 Stem not winged.
........5 Leaves green with white mottles
........5 Leaves green.
..........6 Disk flowers pink (rarely white)
..........6 Disk flowers yellow.
............ 7 Pappus of numerous plumose bristles
............ 7 Pappus absent or of scales or barbellulate bristles.
............ ..8 Cypselas 4-angled; receptacles bearing subulate scales
............ ..8 Cypselas terete, 20-ribbed; receptacles bearing flattened bristles

Key to Asteraceae, Key F: herbaceous composites with leaves not spiny, alternate or basal, heads disciform or discoid (or rarely radiant)

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1 Flowering heads primarily white or yellowish-white
1 Flowering heads variously colored, not primarily white or yellowish white, instead pink, purple, blue, lavender or if partially white then with other predominant colors.
..2 Phyllary bodies linear, their margins entire (phyllary appendages fimbriate; however); leaf margins entire, denticulate or serrulate
..2 Phyllary bodies oblong, ovate, or obovate, both their margins and appendages fimbriate; leaf margins entire, toothed, or pinnately lobed.
....3 Flowers pink, lavender, or purplish; phyllary appendages scarious and spineless, decurrent along the phyllary margin nearly to the phyllary base
....3 Flowers blue; phyllary appendages not or only slightly decurrent along the phyllary margins

Key to Asteraceae, Key from FOV: for editing and augmentation:

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1 Receptacles with paleae or bristles.
..2 Pappus lacking or of scales or awns.
....3 Pappus lacking.
......4 Involucre of dentate or fimbriate phyllaries
......4 Involucre of the pistillate heads a bur with hooked prickles
....3 Pappus present.
........5 Phyllaries dentate or fimbriate
........5 Phyllaries entire
..2 Pappus of bristles.
..........6 Phyllaries fimbriate, dentate, or spiny; leaves often prickly or spiny
..........6 Phyllaries entire, leaves not prickly or spiny.
............ 7 Basal leaves 1-5 mm wide; outer florets pistillate
............ 7 Basal leaves > 5 mm wide (except in Liatris pseudoliatris); florets all perfect.
............ ..8 Phyllaries hooked at tip; heads forming burs at maturity
............ ..8 Phyllaries not hooked at tip; heads not forming burs at maturity.
............ ....9 Heads larger, the involucre 6-15 mm high, with 15-40 phyllaries; leaves with conspicuous (at least at 10× magnification) resin dots
............ ....9 Heads small, the involucre 3.5-6 mm high, with 5-12 phyllaries; leaves without shining punctate glands (except punctate-glandular in Litrisa, of the FL peninsula).
............ ......10 Stem with punctate glands; peduncles punctate-glandular and also hirsutulous; pappus bristles in 2 series; [of FL peninsula]
............ ......10 Stem eglandular, glabrous or spreading-hirsute; peduncles glabrous or stipitate-glandular; pappus bristles in 1 series; [widespread in the Coastal Plain]
1 Receptacles naked.
............ ........11 Pappus lacking or of scales or awns.
............ ..........12 Disk florets blue or purple.
............ ............ 13 Heads few-flowered, aggregated into secondary heads with leafy bracts
............ ............ 13 Heads many-flowered, not aggregated into secondary heads
............ ..........12 Disk florets yellow to yellowish green or reddish to reddish brown.
............ ............ ..14 Cypselas winged and spined; heads sessile in the branch forks
............ ............ ..14 Cypselas not winged and spined; heads not sessile in the branch forks.
............ ............ ....15 Inflorescence elongate, paniculiform, spiciform, or racemiform
............ ............ ....15 Inflorescence a flat-topped corymb, or heads solitary.
............ ............ ......16 Receptacle strongly convex and pointed; plants pineapple-scented
............ ............ ......16 Receptacle flat to convex; plants scented, but not of pineapple
............ ........11 Pappus of barbellate or plumose bristles.
............ ............ ..........18 Perennial; leaves remotely toothed to entire; [of shale barrens]
............ ............ ..........18 Annual; leaves irregularly toothed to pinnatifid; [weed of disturbed soil]
............ ............ ........17 Heads white, whitish, pink, purple, red,
............ ............ ............ ..20 Larger leaves hastate; heads whitish
............ ............ ............ ..20 Leaves not hastate; heads whitish to red or pink to violet or deep purple.
............ ............ ............ ....21 Phyllaries in essentially one series; leaves palmately veined, ovate to reniform
............ ............ ............ ....21 Phyllaries in several series; leaves variously veined, linear to broadly ovate.
............ ............ ............ ......22 Heads white or whitish; [of uplands]
............ ............ ............ ......22 Heads pink to red or violet to deep purple or, rarely, white; [of uplands or wetlands].
............ ............ ............ ........23 Pappus double with inner bristles long and the outer very short
............ ............ ............ 19 Some or all florets pistillate.
............ ............ ............ ............ 25 Phyllaries in essentially one series; fresh plants not strongly scented
............ ............ ............ ............ 25 Phyllaries in several series; fresh plants with a strong, aromatic fragrance
............ ............ ............ ..........24 Leaves white woolly or gray-tomentose, at least beneath (abaxially).
............ ............ ............ ............ ......28 Bristles barbellate to barbellulate; pappi falling
............ ............ ............ ............ ........29 Pappus bristles united at their base, falling as units.
............ ............ ............ ............ ..........30 Blooming Mar-Jul; phyllaries in 3-7 series, sometimes tinged with purple or brown but lacking a conspicuous dark brown spot
............ ............ ............ ............ ..........30 Blooming Jul-Oct; phyllaries in 2-3 series, some or all phyllaries bearing a conspicuous (distal-middle) dark brown spot
............ ............ ............ ............ ........29 Pappus bristles distinct, not united at the base and falling seperately.

Key to Asteraceae, Key G: Herbaceous composites with the leaves alternate or basal and the heads radiate

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1 Ray florets yellow to orange.
..2 Receptacles chaffy (paleate).
....3 Disk florets sterile with style undivided
....3 Disk florets fertile with style bifurcate.
......4 Leaves decurrent down the stem; cypselas strongly flattened and often winged
......4 Leaves not decurrent; cypselas moderately compressed, not winged.
........5 Receptacular bracts connate to form a honeycomb-like structure in which the flowers are set; pappus of 7-12 scales
........5 Receptacular bracts not fused; pappus of awns or a fused crown (coroniform).
..........6 Receptacles flat
..........6 Receptacles subspheric, conical or columnar.
............ 7 Phyllary series unequal (outer longer than inner); cypselae strongly compressed; ray florets subtended by receptacular bracts
............ 7 Phyllary series subequal; cypselae not strongly compressed; ray florets not subtended by receptacular bracts (only the disk flowers with bracts)
..2 Receptacles naked (eplaeate), rarely with bristles.
............ ..8 Pappus of scales or crowns (coroniform).
............ ....9 Heads small, with disk < 5 mm wide and ray florets < 5 mm long
............ ....9 Heads larger, with disk > 5 mm wide and ray florets > 5 mm long
............ ......10 Stems usually winged; cypselae 4-5 angled
............ ......10 Stems not winged; cypselae 3-4+ angled.
............ ........11 Phyllaries in (3-) 4-9+ series; heads borne singly or in arrays; ray florets (the laminae) yellow or orange throughout
............ ........11 Phyllaries in 2-3+ series; heads borne singly; ray florets (the laminae) often bicolored
............ ..8 Pappus of bristles or setiform awns, sometimes also with shorter outer scales.
............ ..........12 Phyllaries in one series.
............ ............ 13 Disk florets fertile, stems with leaves
............ ............ 13 Disk florets sterile, stems bracteate but lacking leaves
............ ..........12 Phyllary in 2+ series.
image of plant
Show caption*© Scott Ward
............ ............ ..14 Pappus double (the outer series consisting of shorter triangular-shaped scales; the inner series consisting of longer bristles).
............ ............ ....15 Ray florets without pappus
............ ............ ....15 Ray florets with pappus (similar to that of disk florets).
............ ............ ......16 Leaves pinnately veined, usually broader and not grasslike
............ ............ ......16 Leaves parallel-veined, linear and grasslike
............ ............ ..14 Pappus simple, only in 1 series.
............ ............ ........17 Ray florets > 1.5 cm long; anthers tailed
............ ............ ........17 Ray florets < 1.5 cm long (to 1.6 cm in Grindelia lanceolata); anthers not tailed (instead obtuse to sagittate).
............ ............ ............ 19 Leaves sessile throughout; cypsela faces strigose to sericeous
............ ............ ............ 19 Proximal leaves petiolate, distal (upper) leaves sessile; cypsela faces smooth, striate, furrowed, or ± rugose
............ ............ ..........18 Plants not taprooted, instead rhizomatous or with woody caudices.
............ ............ ............ ..20 Inflorescences flat-topped corymbs; leaves resinous-punctate, narrow, entire, sessile or subsessile
............ ............ ............ ..20 Inflorescences rarely flat-topped; leaves not resinous-punctate, usually not linear, often toothed and petiolate
1 Ray florets white or whitish to pink or purple.
............ ............ ............ ....21 Receptacles chaffy (paleate).
............ ............ ............ ......22 Phyllaries dry, scarious-margined.
............ ............ ............ ........23 Ray florets 1–5 mm long; heads small in corymbiform arrays
............ ............ ............ ........23 Ray florets > 5 mm long; heads large, terminating the branches
............ ............ ............ ......22 Phyllaries herbaceous, not scarious on margins.
............ ............ ............ ..........24 Ray florets < 2.5 mm long; disk florets sterile, with an undivided style
............ ............ ............ ..........24 Ray florets > 5 mm long; disk florets fertile, with a divided style.
............ ............ ............ ............ 25 Ray florets pink or light purple, > 15 mm long; heads single
............ ............ ............ ............ 25 Ray florets white, 5–10 mm long; heads 20-100 in a compound corymb
............ ............ ............ ....21 Receptacles naked (epaleate).
............ ............ ............ ............ ....27 Achene faces minutely glandular-glochidiate (bearing small gland-like bristles)
............ ............ ............ ............ ....27 Achene faces glabrous or short-strigose but not glandular-glochidiate.
............ ............ ............ ............ ......28 Heads with or without ray florets, if present these reduced in size and less conspicuous than the central, whitish disk florets
............ ............ ............ ............ ......28 Heads with conspicuous ray florets; disk florets typically yellow-colored
............ ............ ............ ............ ........29 Leaves basal; cypselae marginally 2-ribbed; mature plants < 2 dm tall
............ ............ ............ ............ ........29 Leaves cauline; cypselae with ± 10 ribs; mature plants > 2 dm tall
............ ............ ............ ............ ..26 Pappus present, of bristles or scales.
............ ............ ............ ............ ..........30 Heads primarily discoid with reduced ray florets
............ ............ ............ ............ ..........30 Heads radiate with conspicuous ray florets.
............ ............ ............ ............ ............ 31 Taprooted annuals; ray florets 1–7 mm long.
............ ............ ............ ............ ............ ..32 Leaves and stems not fleshy, rarely glabrous; cypselas < 1.4 mm long
............ ............ ............ ............ ............ ..32 Leaves and stems fleshy, mostly glabrous; cypselas > 1.4 mm long
............ ............ ............ ............ ............ 31 Not taprooted and mostly perennials; ray florets > 3 mm long.
image of plant
Show caption*© Richard & Teresa Ware
............ ............ ............ ............ ............ ....33 Ray florets usually > 60; blooming Apr-Oct
............ ............ ............ ............ ............ ....33 Ray florets rarely < 60; blooming late May-Nov.
............ ............ ............ ............ ............ ......34 Receptacles hemispheric to conic; pappus often with 2-4 awns (Boltonia) or lacking awns and coroniform (Astranthium).
............ ............ ............ ............ ............ ........35 Achenes not narrowly winged, the surfaces minutely glandular-glochidiate (bearing small gland-like bristles)
............ ............ ............ ............ ............ ........35 Achenes narrowly winged, the surfaces sometimes puberulent but not glandular-glochidiate
............ ............ ............ ............ ............ ......34 Receptacles flat to slightly convex; pappus lacking awns.
............ ............ ............ ............ ............ ..........36 At least the basal and lower leaves both petiolate and cordate/subcordate at base.
............ ............ ............ ............ ............ ............ 37 Often colonial; inflorescence corymbiform, flat-topped or rounded; outer phyllaries > 1 mm broad
............ ............ ............ ............ ............ ............ 37 Not colonial; inflorescence paniculiform, often elongate; outer phyllaries < 1 mm broad
............ ............ ............ ............ ............ ..........36 Basal and lower leaves not both petiolate and cordate/subcordate at base.
............ ............ ............ ............ ............ ............ ..38 Leaves petiolate or epetiolate but not auriculate or cordate-clasping.
............ ............ ............ ............ ............ ............ ....39 Cypselas not glandular; pappus single or double or in four series.
............ ............ ............ ............ ............ ............ ......40 Leaves silvery-silky on both sides (at least when young), entire
............ ............ ............ ............ ............ ............ ........41 Pappus double, with inner bristles distinctly longer than outer bristles.
............ ............ ............ ............ ............ ............ ..........42 Leaves not rigid, veiny, lanceolate to elliptic or ovate, > 6 mm wide
............ ............ ............ ............ ............ ............ ..........42 Leaves rigid, 1-nerved, linear to linear-spatulate, < 5 mm wide
............ ............ ............ ............ ............ ............ ........41 Pappus simple with all bristles often about the same length.
............ ............ ............ ............ ............ ............ ............ 43 Ray florets white to pink or blue or purple, more numerous (usually 8–30); cypselas glabrous to pubescent but not densely silky.
............ ............ ............ ............ ............ ............ ............ ..44 Ray florets white or pink to blue or purple; involucres 7–12 mm long; phyllaries usually > 1 mm wide.
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