Packera tridenticulata |
Packera layneae |
|
---|---|---|
threetooth ragwort |
Layne's ragwort |
|
Habit | Perennials, 10–30+ cm; taprooted (caudices ascending to erect). | Perennials, 40–70+ cm; taprooted (caudices erect to suberect, branched, stout). |
Stems | 1 or multiple, clustered, usually glabrous, rarely sparsely floccose-tomentose, leaf axils sometimes tomentose. |
1 or 3–4+, clustered, sparsely tomentose to glabrescent. |
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, relatively thick and turgid) petiolate; blades narrowly elliptic or lanceolate to oblanceolate, 40–70+ × 5–20+ mm, bases tapering, margins entire or subentire to weakly and irregularly dentate (especially at apices). |
Cauline leaves | gradually reduced (± petiolate or sessile). |
gradually reduced (distal sessile, bractlike). |
Peduncles | bracteate, glabrous or sparsely tomentose. |
bracteate (bractlets usually red-tipped), sparsely tomentose to glabrate. |
Ray florets | 8–10(–13); corolla laminae 5–8+ mm. |
5 or 8; corolla laminae 12–16 mm. |
Disc florets | 45–60+; corolla tubes 3–3.5 mm, limbs 4–5 mm. |
50–60+; corolla tubes 3.5–4.5 mm, limbs 4.5–5.5 mm. |
Phyllaries | 13 or 21, green, 6–10 mm, sparsely tomentose proximally, glabrous distally. |
13 or 21, dark green proximally, becoming light green distally (tips red), 7–11+ mm, floccose-tomentose proximally. |
Calyculi | inconspicuous. |
conspicuous (bractlets red-tipped). |
Heads | 4–15+ in corymbiform arrays. |
5–12+ in open, cymiform arrays. |
Cypselae | 1.5–2.5 mm, glabrous or sparsely hirtellous on ribs; pappi 5–6 mm. |
2.5–3.5 mm, glabrous; pappi 7–8 mm. |
2n | = 46. |
= 92. |
Packera tridenticulata |
Packera layneae |
|
Phenology | Flowering late May–early Jul. | Flowering early May–early Jul. |
Habitat | Open, dry areas, roadsides, gravelly or sandy slopes, short-grass prairies or sagebrush scrubs | Openings, disturbed areas, in chaparral, serpentine soils |
Elevation | 1000–2000 m (3300–6600 ft) | 300–900 m (1000–3000 ft) |
Distribution |
CO; KS; ND; NE; NM; OK; SD; TX; WY
|
CA |
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 layneae is known only from the foothills of the western slope of the Sierra Nevada. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 601. | FNA vol. 20, p. 590. |
Parent taxa | Asteraceae > tribe Senecioneae > Packera | Asteraceae > tribe Senecioneae > Packera |
Sibling taxa | ||
Synonyms | Senecio tridenticulatus, Senecio acutidens, Senecio compactus, Senecio densus, Senecio oblanceolatus | Senecio layneae, Senecio fastigiatus var. layneae |
Name authority | (Rydberg) W. A. Weber & Á. Löve: Phytologia 49: 48. (1981) | (Greene) W. A. Weber & Á. Löve: Phytologia 49: 47. (1981) |
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