Compilation
Packera tridenticulata

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Name

Identification
Packera tridenticulata (Rydb.) W.A. Weber & Á. Löve [family COMPOSITAE ] (stored under name); Senecio tridenticulatus Rydb. [family COMPOSITAE ] Verified by Greenman, J.M., Senecio compactus (A. Gray) Rydb. ex Porter & Britton [family COMPOSITAE ] Verified by Greenman, J.M., Senecio aureus L. [family COMPOSITAE ]
Related name
  • Packera neomexicana
  • Senecio aureus
  • Packera tridenticulata
  • Senecio compactus
  • Senecio tridenticulatus
  • Senecio metcalfei
Common name
  • Threetooth ragwort, Flora of North America Vol. 20

Flora

Entry for Packera tridenticulata (Rydberg) W. A. Weber & Á. Löve [family COMPOSITAE]
Herbarium
Flora of North America (FNA)
Collection
Flora of North America
Resource Type
Reference Sources
Entry From
Flora of North America, Vol 20,
Names
Packera tridenticulata (Rydberg) W. A. Weber & Á. Löve [family COMPOSITAE], Phytologia, 49: 48. 1981
Senecio tridenticulatus Rydberg [family COMPOSITAE], Bull. Torrey Bot. Club, 27: 175, plate 5, fig. 12. 1900
Senecio acutidens Rydberg [family COMPOSITAE]
Senecio compactus (A. Gray) Rydberg [family COMPOSITAE], 1894. not Kirk 1880
Senecio densus Greene [family COMPOSITAE]
Senecio oblanceolatus Rydberg [family COMPOSITAE]
Treatment Author(s)
Debra K. Trock
Information
Perennials, 10–30+ cm; taprooted (caudices ascending to erect). Stems 1 or multiple, clustered, usually glabrous, rarely sparsely floccose-tomentose, leaf axils sometimes tomentose. 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). Cauline leaves gradually reduced (± petiolate or sessile). Heads 4–15+ in corymbiform arrays. Peduncles bracteate, glabrous or sparsely tomentose. Calyculi incon-spicuous. Phyllaries 13 or 21, green, 6–10 mm, sparsely tomentose proximally, glabrous distally. Ray florets 8–10(–13); corolla laminae 5–8+ mm. Disc florets 45–60+; corolla tubes 3–3.5 mm, limbs 4–5 mm. Cypselae 1.5–2.5 mm, glabrous or sparsely hirtellous on ribs; pappi 5–6 mm. 2n = 46.
Phenology
may (spring), jun-jul (summer)
Altitude range
1000–2000 m;
Distribution
USA Colo.USA Kans.USA Nebr.USA N.Mex.USA N.Dak.USA Okla.USA S.Dak.USA Tex.USA Wyo.
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.

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