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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.



Debra K. Trock

Biennial or perennial herb 3–100+ cm from rhizome or taproot with thin branched fibrous roots, loosely hairy to glabrous. Stem: 1–several. Leaf: pinnate or generally simple, basal and proximal cauline generally petioled, mid sessile, reduced, distal bract-like. Inflorescence: heads discoid or radiate, in compact or open cyme-like clusters, rarely single; involucre generally bell-shaped (cylindric); main phyllaries generally 8, 13, or 21 in 1 series, reflexed in fruit, green to ± red, linear, glabrous or hairy, subtended by a few reduced outer phyllaries, not black-tipped; receptacle epaleate. Ray flower: 0–13(21); corolla pale yellow to deep orange-red. Disk flower: 20–80+; corolla bell-shaped to tubular, lobes 5 erect to recurved, generally yellow (to deep orange-red); style tips truncate. Fruit: cylindric, generally prominently ribbed, glabrous or stiff-hairy; pappus of white minutely barbed bristles.
64 species: North America, 1–2 in Siberia. (J.G. Packer, Canadian botanist, b. 1929) [Trock 2006 FNANM 20:570–602] Formerly in Senecio. The common names groundsel, ragwort, and butterweed are applied to species of both Packera and Senecio.

Key to Packera

1. Heads discoid

2. Plants < 15 cm, ± scapose; cauline leaves much reduced; heads generally < 5 ..... P. werneriifolia (2)

2' Plants generally > 15 cm; cauline leaves gradually reduced; heads generally > 5

3. Caudex taprooted; leaves thin; heads generally > 10, phyllaries deep green or ± red-tipped; generally below subalpine elevations ..... P. indecora (2)

3' Caudex weakly spreading and fibrous rooted; leaves thick, firm; heads generally 4–8, phyllaries deep red or green with ± red tips; often subalpine to alpine elevations ..... P. pauciflora (2)

1' Heads radiate, some with rays barely exceeding phyllaries

4. Basal leaves ± pinnately lobed

5. Herbage glabrous or at most sparsely and irregularly hairy when young

6. Caudex taprooted; peduncle conspicuously bracted; plants in Sierra Nevada and e ..... P. multilobata (2)

6' Caudex fibrous rooted; peduncle not bracted or bracts inconspicuous; plants west of High Sierra Nevada

7. Plants stout or slender, generally < 50 cm; basal leaves with 1–3 pairs of lateral lobes, terminal lobes ± round, ultimate margins evenly, regularly incised, sinuses rounded, bases ± cordate; heads (3)8–15+ ..... P. bolanderi var. bolanderi

7' Plants large, robust, generally > 50 cm; basal leaves with 2–6+ pairs of lateral lobes, terminal lobes ovate to oblong, ultimate margins irregularly incised, bases tapered; heads 15–50+ ..... P. breweri

5' Herbage generally hairy or becoming glabrous near flower time

8. Heads generally 3–6; plants generally <= 3 dm; basal leaves generally <= 3 cm, with 1–3 pairs of lateral lobes ..... P. ionophylla (2)

8' Heads 5–30+; plants 2–5+ dm; basal leaves generally > 4 cm, with 2–6 pairs of lateral lobes

9. Basal leaves persistent; heads small, rays 7–10 mm; herbage evenly but lightly hairy ..... P. multilobata (2)

9' Basal leaves withering before flower; heads large, rays 10–15 mm; herbage densely hairy to becoming glabrous with age ..... P. eurycephala

10. Leaves irregularly lobed or dissected, lateral lobes coarsely dentate, midribs winged; disturbed sites, woodland, roadsides ..... var. eurycephala

10' Leaf margins finely dissected, lateral lobes also dissected, midribs not winged; serpentine soils, rocky sites ..... var. lewisrosei

4' Basal leaves with margins various but not (or weakly) lobed

11. Herbage hairy to becoming glabrous at flower time

12. Rays red-orange; heads generally 1–3; plants generally on serpentine ..... P. greenei

12' Rays yellow; heads 2–many; plants of various soils

13. Basal leaves round to widely ovate, obovate or spoon-shaped, petiole >> blade

14. Fruit 0.7–1 mm; phyllaries 6–8 mm; disk flowers 35–50+ ..... P. bernardina

14' Fruit 2–2.5 mm; phyllaries 7–10 mm; disk flowers 60–75+ ..... P. ionophylla (2)

13' Basal leaves ovate, elliptic, lanceolate, oblanceolate or narrowly spoon-shaped, petiole < or > blade

15. Plants generally 7–15 cm; heads generally < 5 ..... P. werneriifolia (2)

15' Plants 10–70+ cm; heads >= 5

16. Herbage sparsely tomentose, becoming glabrous; ray 12–16 mm, plants only on serpentine ..... P. layneae

16' Herbage canescent, woolly, or densely tomentose, sometimes becoming glabrous; ray 8–10+ mm, plants of various habitats

17. Leaves ovate, elliptic, or widely lanceolate; phyllaries tomentose, fruit 2.5–3.5+ mm ..... P. cana

17' Leaves lanceolate to oblanceolate; phyllaries glabrous, fruit 1.5–2 mm ..... P. macounii

11' Herbage glabrous or at most tomentose to woolly at flower on proximal stem, in leaf axils and/or at bases of heads

18. Leaves thick, firm, glaucous ..... P. clevelandii

18' Leaves thick or thin, glabrous to sparsely tomentose

19. Heads 6–20+

20. Leaves widely lanceolate to ± hastate, margins sharply dentate, plants 5–7+ dm; heads 12–20+, phyllaries light green ..... P. pseudaurea var. pseudaurea

20' Leaves ovate, elliptic, oblanceolate, spoon-shaped, oblong or ± reniform, margins entire to dentate or weakly lobed, plants 1–8 dm; heads 6–20+, phyllaries dark green often red-tipped

21. Caudex taprooted; leaves not noticeably firm; heads generally eradiate or with ray 3–5 mm ..... P. indecora (2)

21' Caudex stout and fibrous-rooted; leaves ± thick, firm; heads radiate, ray 5–10 mm ..... P. streptanthifolia var. streptanthifolia

19' Heads 1–6(8)

22. Leaves reniform to ± round; plants only in recently burned chaparral on gabbroic soils ..... P. ganderi

22' Leaves elliptic, ovate, oblanceolate, obovate, spoon-shaped, or at most ± reniform; plants of various habitats, but not in chaparral

23. Ray 5–7 mm, deep orange-yellow; heads generally > 4 ..... P. pauciflora (2)

23' Ray 6–12+ mm, yellow; heads generally 1–4

24. Phyllaries densely tomentose; head (1)4; ray 6–10+ mm ..... P. hesperia

24' Phyllaries glabrous; head 1(3); ray 7–12+ mm ..... P. subnuda var. subnuda


Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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