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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

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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  Hymenopappus

3 Pappus of 6-10 scales; [historical waif]  Hymenoxys anthemoides

2 Leaves unlobed, or if pinnately lobed, the segments broad (> 3 mm wide).

4 Receptacle paleate  Verbesina

4 Receptacle epaleate.

5 Pappus scales rudimentary, crown-like  Tanacetum

5 Pappus scales conspicuous.

6 Phyllaries 25-125 in 3-9 series; receptacles flat or slightly convex  Grindelia

6 Phyllaries 6-25 (-60) in 2-3 series; receptacles globose.

7 Stems not winged  Gaillardia

7 Stems winged from node to node  Helenium flexuosum

1 Disc flowers pink, purple, or white

8 Receptacle paleate  Marshallia

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]  Thurovia triflora

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  Elephantopus

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  Pseudelephantopus spicatus

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]  Hartwrightia floridana

13 Involucres 4-15+ mm in diameter; flowers 20-80 per head; [SC, GA, and FL westwards]  Hymenopappus

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  Centaurea

16 Pappus of an outer setiform scales (appearing as "flattened bristles"  Leuzea repens

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  Centaurea

17 Plant an annual; flowers pale to medium blue, flowering Apr-Jun  Cyanus depressus

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"  Stokesia laevis

18 Peripheral flowers of the heads similar to the interior flowers, all disc flowers.

19 Annuals; cypselas not ribbed  Cyanthillium cinereum

19 Perennials; cypselas 8-10-ribbed.

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  Centratherum punctatum

20 Heads not subtended by leafy bracts; pappus of an inner series of scales or bristles and an outer series of bristles, persistent  Vernonia

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

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1 Receptacles chaffy (paleate).

2 Phyllaries dry, scarious-margined.

3 Ray florets 1-5 mm long; heads small in corymbiform arrays  Achillea

3 Ray florets > 5 mm long; heads large, terminating the branches  Anthemis

2 Phyllaries herbaceous, not scarious on margins.

4 Ray florets < 2.5 mm long; disk florets sterile, with an undivided style  Parthenium

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  Echinacea

5 Ray florets white, 5-10 mm long; heads 20-100 in a compound corymb  Verbesina

1 Receptacles naked (epaleate).

6 Pappus absent or coroniform.

7 Achene faces minutely glandular-glochidiate (bearing small gland-like bristles)  Astranthium

7 Achene faces glabrous or short-strigose but not glandular-glochidiate.

8 Leaves basal; cypselae marginally 2-ribbed; mature plants < 2 dm tall  Bellis perennis

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  Leucanthemum

9 Heads 5-60+ in corymbiform arrays  Tanacetum

6 Pappus present, of bristles or scales.

10 Heads primarily discoid with reduced ray florets  Hymenopappus

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  Erigeron

12 Leaves and stems fleshy, mostly glabrous; cypselas > 1.4 mm long  Symphyotrichum

11 Not taprooted and mostly perennials; ray florets > 3 mm long.

13 Ray florets usually > 60; blooming Apr-Oct  Erigeron

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)  Astranthium

15 Achenes narrowly winged, the surfaces sometimes puberulent but not glandular-glochidiate  Boltonia

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  Eurybia

17 Not colonial; inflorescence paniculiform, often elongate; outer phyllaries < 1 mm broad  Symphyotrichum

16 Basal and lower leaves not both petiolate and cordate/subcordate at base.

18 Leaves sessile and auriculate or cordate-clasping  Symphyotrichum

18 Leaves petiolate or epetiolate but not auriculate or cordate-clasping.

19 Cypselas glandular; pappus double  Oclemena

19 Cypselas not glandular; pappus single or double or in four series.

20 Leaves silvery-silky on both sides (at least when young), entire  Symphyotrichum

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  Doellingeria

22 Leaves rigid, 1-nerved, linear to linear-spatulate, < 5 mm wide  Ionactis

21 Pappus simple with all bristles often about the same length.

23 Ray florets white, few (usually 3-8); cypselas densely silky  Sericocarpus

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  Symphyotrichum

24 Ray florets white or pink to blue or purple; involucres 7-12 mm long; phyllaries usually > 1 mm wide.

Show caption*© Scott Ward                                                     25 Phyllaries glandular  Eurybia

25 Phyllaries not glandular.

26 Phyllaries long-attenuate or loose and spreading  Symphyotrichum

26 Phyllaries appressed, not long-attenuate.

27 Plants coarse-hairy; lowest leaves > 5 cm wide  Aster

27 Plants glabrous to hairy; lowest leaves < 3 cm wide  Eurybia