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Asteraceae Group 1
See list of 19 genera in this group-
1a. Pappus absent; plants annual; rays yellow
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2a. Involucral bracts membranaceous to herbaceous, not prominently keeled; peduncles not swollen; stems with foliaceous leaves
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2b. Involucral bracts becoming enlarged with an indurate, keeled midrib after anthesis; peduncles conspicuously swollen; stem with minute, bracteal leaves
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1b. Pappus present in some form; plants annual, biennial, or perennial; rays of various colors
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3a. Pappus composed partly or entirely of scales (bristles may also be present)
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4a. Pappus composed entirely of scales, the scales numerous; rays blue (rarely pink or white); involucre 9–15 mm tall
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4b. Pappus of 5 scales and 5–10 slender bristles; rays yellow; involucre 4–7 mm tall
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5a. Pappus composed of two different elements—5 or 10 flat scales (these sometimes inconspicuous) along with 5–35 capillary bristles [Fig. 428]; involucre composed of bracts of ± equal length, 4–14 mm tall; plants annual or perennial
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5b. Pappus of 5 or fewer bristle-tipped scales; involucre composed of two dissimilar series of bracts, the outer ones much shorter than the inner ones, 7–16 mm tall; plants annual
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3b. Pappus composed entirely of slender bristles
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6a. Pappus bristles smooth or barbellate, but not pinnately branched [Fig. 424]
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7a. Cypsela body terete or several-angled (note: this character can often be successfully assessed with the flowering ovary)
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8a. Cypsela body muricate, at least in the apical portion, tipped by a long, slender beak [Fig. 472]
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9a. Flowers pink, purple, white, yellow-white, or green-white; capitula with 5–16 (–26) flowers [Fig. 436]
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10a. Plants taprooted annuals or biennials; pappus bristles white, relatively soft; involucre composed of 2 series of principal bracts, the outer much shorter than the inner
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10b. Plants fibrous-rooted perennials, from short or long rhizomes or a caudex; pappus bristles sordid white to light brown, relatively stiff; involucre variable, either composed of 2 series of principal bracts (i.e., a long inner series and a short, outer series) or with 3 or more series of principal bracts
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7b. Cypsela body evidently compressed
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11a. Cypsela body without an enlarged disk at the apex where the pappus attaches, also lacking a beak; capitula with 80–250 flowers
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11b. Cypsela with an enlarged disk at the apex where the pappus attaches, with or without a beak [Figs. 429,430]; capitula with 5–56 flowers
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12a. Capitula with 5 flowers
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12b. Capitula with 13–55 flowers
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13a. Plants annual or biennial, without rhizomes; involucre 6–12 mm long in flower, becoming 12–15 mm long in fruit (except L. hirsuta, with involucres 15–22 mm long in fruit and cypsela bodies with a single nerve on each face); cypsela body with 1 or 3–9 nerves on each face
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13b. Plants perennial, from deep-seated rhizomes; involucre 12–15 mm long in flower, becoming 15–20 mm in fruit; cypsela body with 4–6 nerves on each face
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6b. Pappus bristles plumose (i.e., pinnately branched) [Fig. 391]
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14a. Involucre composed of 1 series of involucral bracts of equal length; leaf blades long and slender, grass-like; cypsela body 10–25 mm long excluding the beak
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14b. Involucre calyculate or with bracts of differing lengths; leaf blades relatively wider, not grass-like; cypsela body 2–7.5 mm long excluding the beak
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15a. Stems resembling a scape, without leaves or with few, very small leaves; cypsela body 4–7.5 mm long excluding the apical beak
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16a. Receptacle with chaff; cypselas muricate, the inner terminated by a slender beak
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16b. Receptacle without chaff; cypsela body rugulose, without a beak
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17a. Reproductive stem with (1–) 2–7 capitula, with (7–) 10 or more scale-like bracts, these especially numerous just below the involucres; pubescence of plant strictly simple (i.e., of unbranched hairs); pappus in 1 series of plumose hairs
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17b. Reproductive stem with 1 (–2) capitulum, with 0–3 scale-like bracts; pubescence of plant, at least in part, compound, with 2 or more branches; pappus of inner flowers in 2 series, the outer series not plumose
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15b. Stems not resembling a scape, definitely leafy; cypsela body 2–4 (–6) mm long excluding the apical beak (when present)
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18a. Outer series of involucral bracts numbering (8–) 13 or more, lanceolate to broad-linear, 0.5–1.5 (–3) mm wide; cypsela body apically narrowed but without a beak
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18b. Outer series of involucral bracts numbering (3–) 5, ovate to broad-lanceolate, 3–5 (–8) mm wide; cypsela body terminated by a slender beak nearly as long as or longer than the body proper
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Each photo represents one genus in this subgroup.