Packera tridenticulata |
Packera hesperia |
|
---|---|---|
threetooth ragwort |
serpentine groundsel, Siskiyou butterweed, western ragwort |
|
Habit | Perennials, 10–30+ cm; taprooted (caudices ascending to erect). | Perennials, 7–15+ cm; fibrous-rooted (caudices relatively slender). |
Stems | 1 or multiple, clustered, usually glabrous, rarely sparsely floccose-tomentose, leaf axils sometimes tomentose. |
1, glabrous or sparsely 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). |
(and proximal cauline) petiolate; blades ovate, oblanceolate, or spatulate, 10–30 × 5–20 mm, bases tapering, sometimes obtuse, margins entire, subentire, or dentate. |
Cauline leaves | gradually reduced (± petiolate or sessile). |
abruptly reduced (sessile, clasping; bractlike, entire). |
Peduncles | bracteate, glabrous or sparsely tomentose. |
bracteate (bractlets red-tinged), densely lanate-tomentose. |
Ray florets | 8–10(–13); corolla laminae 5–8+ mm. |
(8–)13; corolla laminae 6–10+ mm. |
Disc florets | 45–60+; corolla tubes 3–3.5 mm, limbs 4–5 mm. |
35–50+; corolla tubes 2.5–3.5 mm, limbs 3–4 mm. |
Phyllaries | 13 or 21, green, 6–10 mm, sparsely tomentose proximally, glabrous distally. |
(13–)21, green (tips red or dark red), densely tomentose proximally. |
Calyculi | inconspicuous. |
conspicuous (bractlets narrow, red-tinged). |
Heads | 4–15+ in corymbiform arrays. |
1–4+ in corymbiform arrays. |
Cypselae | 1.5–2.5 mm, glabrous or sparsely hirtellous on ribs; pappi 5–6 mm. |
1.5–2 mm, glabrous; pappi 5–6 mm. |
2n | = 46. |
= 46. |
Packera tridenticulata |
Packera hesperia |
|
Phenology | Flowering late May–early Jul. | Flowering mid Apr–mid Jun. |
Habitat | Open, dry areas, roadsides, gravelly or sandy slopes, short-grass prairies or sagebrush scrubs | Serpentine derived soils, open woodland scrub |
Elevation | 1000–2000 m (3300–6600 ft) | 500–2500 m (1600–8200 ft) |
Distribution |
CO; KS; ND; NE; NM; OK; SD; TX; WY
|
CA; OR
|
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.) |
Of conservation concern. Packera hesperia is known only from the Siskiyou Mountains. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 601. | FNA vol. 20, p. 589. |
Parent taxa | Asteraceae > tribe Senecioneae > Packera | Asteraceae > tribe Senecioneae > Packera |
Sibling taxa | ||
Synonyms | Senecio tridenticulatus, Senecio acutidens, Senecio compactus, Senecio densus, Senecio oblanceolatus | Senecio hesperius, Senecio auleticus |
Name authority | (Rydberg) W. A. Weber & Á. Löve: Phytologia 49: 48. (1981) | (Greene) W. A. Weber & Á. Löve: Phytologia 49: 47. (1981) |
Web links |