Packera tridenticulata |
Packera neomexicana |
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threetooth ragwort |
New Mexico groundsel |
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Habit | Perennials, 10–30+ cm; taprooted (caudices ascending to erect). | Perennials, biennials, or annuals, 20–50+ cm; fibrous-rooted, taprooted, or ± rhizomatous (bases branched, horizontal or ascending to erect). | ||||||||
Stems | 1 or multiple, clustered, usually glabrous, rarely sparsely floccose-tomentose, leaf axils sometimes tomentose. |
1 or 2–5+, clustered, lanate- or arachno-tomentose or glabrescent. |
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Basal leaves | (and proximal cauline, relatively thick and turgid) petiolate; blades lanceolate or narrowly oblanceolate, 20–40+ × 5–15 mm, bases tapering, margins usually entire, sometimes sub-pinnatisect (apices subentire or dentate). |
(often abaxially cyanic) petiolate (petioles hairy to glabrate); blades ovate to lanceolate or narrowly lanceolate, 20–60+ × 10–30+ mm, bases abruptly contracted to tapering, margins subentire or denticulate to subserrate (abaxial faces usually tomentose, adaxials frequently glabrate). |
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Cauline leaves | gradually reduced (± petiolate or sessile). |
gradually or abruptly reduced (proximal petiolate, similar to basals; mids and distals sessile, lanceolate, entire). |
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Peduncles | bracteate, glabrous or sparsely tomentose. |
conspicuously bracteate, usually hairy. |
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Ray florets | 8–10(–13); corolla laminae 5–8+ mm. |
(5–)8 or 13; corolla laminae 4–10 mm. |
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Disc florets | 45–60+; corolla tubes 3–3.5 mm, limbs 4–5 mm. |
40–60+; corolla tubes 1.5–2.5 mm, limbs 3.5–4.5 mm. |
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Phyllaries | 13 or 21, green, 6–10 mm, sparsely tomentose proximally, glabrous distally. |
13 or 21, green or yellowish, 4–7+ mm, tomentose to glabrescent. |
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Calyculi | inconspicuous. |
conspicuous. |
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Heads | 4–15+ in corymbiform arrays. |
3–20+ in open or compact, corymbiform to subumbelliform arrays (subtended by smaller arrays arising from leaf axils). |
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Cypselae | 1.5–2.5 mm, glabrous or sparsely hirtellous on ribs; pappi 5–6 mm. |
1.5–2.5 mm, usually hirtellous on ribs, sometimes glabrous; pappi 5–6+ mm. |
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2n | = 46. |
= 44, 46, 92. |
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Packera tridenticulata |
Packera neomexicana |
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Phenology | Flowering late May–early Jul. | |||||||||
Habitat | Open, dry areas, roadsides, gravelly or sandy slopes, short-grass prairies or sagebrush scrubs | |||||||||
Elevation | 1000–2000 m (3300–6600 ft) | |||||||||
Distribution |
CO; KS; ND; NE; NM; OK; SD; TX; WY
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AZ; CO; NM; UT; w Mexico
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Discussion | Packera tridenticulata is found throughout the central High Plains, in the foothills of the Rocky Mountains, and in high valleys to the west of the Rocky Mountain front. It tends to grow in clumps; the multiple stems arise from well-developed taproots. It apparently hybridizes with P. neomexicana var. mutabilis where their ranges overlap. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 3 (3 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 20, p. 601. | FNA vol. 20, p. 593. | ||||||||
Parent taxa | Asteraceae > tribe Senecioneae > Packera | Asteraceae > tribe Senecioneae > Packera | ||||||||
Sibling taxa | ||||||||||
Subordinate taxa | ||||||||||
Synonyms | Senecio tridenticulatus, Senecio acutidens, Senecio compactus, Senecio densus, Senecio oblanceolatus | Senecio neomexicanus | ||||||||
Name authority | (Rydberg) W. A. Weber & Á. Löve: Phytologia 49: 48. (1981) | (A. Gray) W. A. Weber & Á. Löve: Phytologia 49: 47. (1981) | ||||||||
Web links |