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threetooth ragwort

Piedmont ragwort

Habit Perennials, 10–30+ cm; taprooted (caudices ascending to erect). Perennials, 25–60+ cm; fibrous-rooted (caudices branched).
Stems

1 or multiple, clustered, usually glabrous, rarely sparsely floccose-tomentose, leaf axils sometimes tomentose.

1 or 2–3, clustered, glabrous or leaf axils sparsely hairy.

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 narrowly ovate to ovate (2–3 times pinnately dissected, ultimate lobes mostly linear to filiform), 50–80 × 30–50 mm, bases ± truncate or auriculate, ultimate margins entire or remotely dentate.

Cauline leaves

gradually reduced (± petiolate or sessile).

gradually reduced (petiolate or sessile, similar to basals).

Peduncles

bracteate, glabrous or sparsely tomentose.

bracteate or ebracteate, glabrous.

Ray florets

8–10(–13);

corolla laminae 5–8+ mm.

8–10(–13);

corolla laminae 8–12 mm.

Disc florets

45–60+;

corolla tubes 3–3.5 mm, limbs 4–5 mm.

35–50+;

corolla tubes 2–3 mm, limbs 1.5–2.5 mm.

Phyllaries

13 or 21, green, 6–10 mm, sparsely tomentose proximally, glabrous distally.

(13–)21, green, 4–6 mm, glabrous (tips sometimes hair-tufted).

Calyculi

inconspicuous.

0.

Heads

4–15+ in corymbiform arrays.

10–30+ in open, corymbiform arrays.

Cypselae

1.5–2.5 mm, glabrous or sparsely hirtellous on ribs;

pappi 5–6 mm.

0.75–1.5 mm, hairy on ribs;

pappi 3–4 mm.

2n

= 46.

Packera tridenticulata

Packera millefolium

Phenology Flowering late May–early Jul. Flowering early May–mid Jun.
Habitat Open, dry areas, roadsides, gravelly or sandy slopes, short-grass prairies or sagebrush scrubs Open areas along streams, rock outcrops in thin, granitic-derived soils
Elevation 1000–2000 m (3300–6600 ft) 400–900 m (1300–3000 ft)
Distribution
from FNA
CO; KS; ND; NE; NM; OK; SD; TX; WY
[WildflowerSearch map]
from FNA
GA; NC; SC; VA
[BONAP county map]
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 millefolia is known only from granitic soils in the southern Appalachians. It is similar in overall aspect to the widespread P. anonyma; it differs by its 2–3 times pinnately dissected leaves.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 20, p. 601. FNA vol. 20, p. 591.
Parent taxa Asteraceae > tribe Senecioneae > Packera Asteraceae > tribe Senecioneae > Packera
Sibling taxa
P. anonyma, P. antennariifolia, P. aurea, P. bernardina, P. bolanderi, P. breweri, P. cana, P. cardamine, P. castoreus, P. clevelandii, P. contermina, P. crocata, P. cymbalaria, P. cynthioides, P. debilis, P. dimorphophylla, P. eurycephala, P. fendleri, P. flettii, P. franciscana, P. ganderi, P. glabella, P. greenei, P. hartiana, P. hesperia, P. hyperborealis, P. indecora, P. ionophylla, P. layneae, P. macounii, P. malmstenii, P. millefolium, P. millelobata, P. multilobata, P. musiniensis, P. neomexicana, P. obovata, P. ogotorukensis, P. pauciflora, P. paupercula, P. plattensis, P. porteri, P. pseudaurea, P. quercetorum, P. sanguisorboides, P. schweinitziana, P. spellenbergii, P. streptanthifolia, P. subnuda, P. tampicana, P. texensis, P. tomentosa, P. werneriifolia
P. anonyma, P. antennariifolia, P. aurea, P. bernardina, P. bolanderi, P. breweri, P. cana, P. cardamine, P. castoreus, P. clevelandii, P. contermina, P. crocata, P. cymbalaria, P. cynthioides, P. debilis, P. dimorphophylla, P. eurycephala, P. fendleri, P. flettii, P. franciscana, P. ganderi, P. glabella, P. greenei, P. hartiana, P. hesperia, P. hyperborealis, P. indecora, P. ionophylla, P. layneae, P. macounii, P. malmstenii, P. millelobata, P. multilobata, P. musiniensis, P. neomexicana, P. obovata, P. ogotorukensis, P. pauciflora, P. paupercula, P. plattensis, P. porteri, P. pseudaurea, P. quercetorum, P. sanguisorboides, P. schweinitziana, P. spellenbergii, P. streptanthifolia, P. subnuda, P. tampicana, P. texensis, P. tomentosa, P. tridenticulata, P. werneriifolia
Synonyms Senecio tridenticulatus, Senecio acutidens, Senecio compactus, Senecio densus, Senecio oblanceolatus Senecio millefolium, Senecio memmingeri
Name authority (Rydberg) W. A. Weber & Á. Löve: Phytologia 49: 48. (1981) (Torrey & A. Gray) W. A. Weber & Á. Löve: Phytologia 49: 47. (1981)
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