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Asteraceae Group 4

See list of 37 genera in this group
  • 1a. Pappus composed of capillary bristles (also with an additional series of minute, slender scales in some Erigeron, with a short, outer crown in Callistephus) [Figs. 438,468]
    • 2a. Plants subdioecious, each capitulum composed almost entirely of unisexual flowers; stems scaly bracteate; well-developed leaves all basal, the blades palmately lobed 
 [Fig. 442] (in part)
    • 2b. Plants polygamous, each capitulum with the ray flowers unisexual and carpellate and the disk flowers bisexual; stems with leaves; leaves various, but neither all basal nor with palmately lobed blades
      • 3a. Rays up to 2 mm long, shorter than to scarcely exceeding the pappus, often inconspicuous in drying
        • 4a. Involucral bracts glabrous and eciliate; ± glabrous saltmarsh plants 
 (in part)
        • 4b. Involucral bracts pubescent or ciliate or both; plants often with pubescent stems and/or leaf blades, at least with marginal cilia on the leaf blades, not occurring in saltmarshes
          • 5a. Involucre with 3 or 4 series of foliaceous bracts of ± equal length; style appendages acute to acuminate (in part)
          • 5b. Involucre with green but not at all foliaceous bracts, the bracts of similar or dissimilar length; style appendage acute to, more commonly, obtuse 
 (in part)
      • 3b. Rays 2–35 mm long, exceeding the pappus, evident even in drying [Figs. 451,462]
        • 6a. Leaf blades pinnately lobed, each lobe terminating in a spine; involucral bracts ± spinulose-margined
        • 6b. Leaf blades entire to toothed (sometimes lobed in Callistephus), not spiny; involucral bracts without spinulose margins (though the apex sometimes with a 
spine tip)
          • 7a. Surface of ovary with minute stalked glands [Fig. 438]; capitula nodding in bud; leaves reduced in size toward the base, the lowest scale-like
          • 7b. Surface of ovary without glands; capitula erect in bud (spreading or sometimes nodding in Ionactis); leaves larger toward the stem base
            • 8a. Capitula frequently in glomerules, with 3–8 ray flowers [Fig. 451]; foliage leaves with sessile glands
            • 8b. Capitula usually borne singly at the ends of peduncles, with 7–100 or more ray flowers [Figs. 462,466]; foliage leaves without glands ( Oligoneuron album with obscure resin glands, and the bracteal leaves of some Symphyotrichum and Eurybia with stipitate glands)
              • 9a. Basal leaves gradually tapering to an elongate petiole, the blade and petiole combined commonly 30–40 cm long; involucral bracts usually with a thin anthocyanic stripe along each margin; rare escape in New England
              • 9b. Basal leaves shorter than 30 cm, lacking petioles, and/or abruptly contracted to a petiole; involucral bracts rarely with marginal anthocyanic stripes, anthocyanin, if present, usually distributed near the center and/or apex of the bract (rarely throughout); primarily native plants, though some species weedy
                • 10a. Involucral bracts in three series—the outer series foliaceous and green ± throughout, the inner series membranaceous to scarious; capitula solitary and the ends of branches, 6–8 cm in diameter; involucre double—outer series a short, membranous crown, inner series of minutely barbellate bristles
                • 10b. Involucral bracts variable, usually not foliaceous (except in a 
few Symphyotrichum); capitula solitary, in glomerules, or few to many 
along branches; involucre single or double, but not with an outer, membranous crown
                  • 11a. Involucral bracts of ± equal length (sometimes with some very small bracts near the base of the involucre), green throughout or in large part, but not foliaceous; style appendage acute to, more commonly, obtuse (in part)
                  • 11b. Involucral bracts of dissimilar lengths, usually pale at the base with an apically dilated green midzone [Figs. 462,464,466], less commonly foliaceous or anthocyanic (green throughout in Doellingeria); style appendages acute to acuminate
                    • 12a. Pappus bristles of 2 distinctly uneven lengths—a very short outer series and 1 or 2 series of elongate bristles of nearly even length [Fig. 438]; involucral bracts neither foliaceous nor with a distinct, green apical zone [Fig. 396]
                      • 13a. Longer series of pappus bristles thickened at the apex; involucral bracts with raised midvein, but not keeled; rays not coiling; disk flowers abruptly expanded apically; ovaries terete
                      • 13b. Longer series of pappus bristles slender at the apex; involucral bracts somewhat keeled; rays coiling; disk flowers tubular; ovaries compressed
                    • 12b. Pappus bristles all elongate, in 2 or 3 series of nearly even length [Fig. 468]; involucral bracts with a distinct green apical zone or entirely foliaceous in a few species (anthocyanic pigments sometimes also present) [Figs. 462,464,466]
                      • 14a. Disk corollas white; leaf blades with sessile resin glands (these sometimes obscure); pappus bristles thickened at apex 
 (in part)
                      • 14b. Disk corollas yellow or becoming purple, red, or red-brown; leaf blades without sessile resin glands (though the bracteal leaves stipitate-glandular in a few species); pappus bristles slender at the apex or thickened in some Eurybia

                        • 15a. Rays 2–3 mm long [Figs. 452,459]; capitulescence very slender, resembling a thyrse, sometimes with 1 or more elongate, slender, ascending branches resembling the main axis; disk flowers persistently pale yellow (in part)
                        • 15b. Rays 3–30 mm long [Figs. 462,465]; capitulescence resembling a panicle or corymb or infrequently composed 
of 1 or few capitula; disk flowers yellow, becoming purple, 
red, or red-brown in age
                          • 16a. Outer and middle involucral bracts less than 2.5 times as long as wide, rounded to obtuse at the apex, densely ciliate along the margins, with a thumbnail to rhombic shaped chlorophyllous zone at the tip [Fig. 407]; capitulescence corymb-like; pappus bristles sometimes thickened at the apex; ovary terete
                          • 16b. Involucral bracts more than 3 times as long as wide, obtuse to acuminate at the apex, eciliate or sparingly ciliate along the margins, with a rhombic to basally tapering chlorophyllous zone at the tip or entirely foliaceous [Figs. 462,464,465]; capitulescence commonly panicle-like when well formed; pappus bristles slender at the apex; ovary compressed in most species (in part)
  • 1b. Pappus composed entirely of scales, awns, or a short crown, or absent

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 Show photos of:   Each photo represents one genus in this subgroup.