OregonFlora: Packera breweri vs. Packera

	Packera breweri	Packera
		ragwort
Habit		Herbs annual, biennial, or perennial, 3–100+ cm; caudices rhizomatous or taprooted, often with thin, branched, fibrous roots.
Stems		single or clustered; erect, glabrous or pubescent.
Leaves		alternate; basal and cauline; blades elliptic, lanceolate, linear, lyrate, orbiculate; ovate, reniform, or spatulate, often pinnately lobed to pinnatifid or pinnatisect; margins entire or crenate, dentate, or serrate to denticulate, pinnately veined; cauline much reduced; upper leaves bract-like, petiolate or sessile.
Inflorescences		terminal heads; in compact or open corymb-, cyme-, or subumbel-like arrays, rarely heads solitary.
Involucres		campanulate to cylindric.
Receptacles		flat; paleae 0.
Ray florets		0 or 5–13, pistillate, fertile, pale yellow to orange-red.
Disc florets		20–80+; bisexual, fertile; corollas pale yellow to orange-red; tubes ? campanulate; lobes 5; erect to recurved, usually ± deltate; style branch tips usually truncate.
Phyllaries		persistent, 8, 13, or 21 in 1 series.
Calyculi		0 or 1–5+ bractlets.
Fruits		cylindric, tan to dark brown, glabrous or pubescent; ribs usually 5–10, pappi of white, barbellulate bristles.
Heads		radiate or discoid.

	Packera breweri	Packera
Distribution	[WildflowerSearch map] [BONAP county map]	[BONAP county map]
Discussion		North America. 66 species; 10 species treated in Flora. Packera is a segregate of Senecio. It contains species that were traditionally referred to as “aureoid senecios,” an informal group that was first recognized by Asa Gray. Base chromosome numbers of x=22 or 23 (as opposed to x=10) and a suite of morphological characters have traditionally been used in the circumscription of the genus. More recent molecular and palynological studies lend good support for the recognition of the genus. Species boundaries in the genus are notoriously imprecise, and polyploidy is common. Some species hybridize to some extent with others whenever they come into contact, while others are never known to hybridize. Authors of some studies on the more widespread species propose dividing the species into many varieties based on subtle differences in vegetative morphology, which are often overlapping and inconsistent, and on populational differences due to polyploidy. While recognizing the value of such work in understanding evolutionary relationships, I have taken the view that splitting these species into many varieties based on these difficult characters does little to help with their identification in the field, and these proposed varieties are not supported by molecular data.
Source		Flora of Oregon, volume 2, page 320 Debra Trock
Sibling taxa	P. bolanderi, P. cana, P. eurycephala, P. flettii, P. hesperia, P. macounii, P. porteri, P. pseudaurea, P. streptanthifolia, P. subnuda
Subordinate taxa		P. bolanderi, P. cana, P. eurycephala, P. flettii, P. hesperia, P. macounii, P. porteri, P. pseudaurea, P. streptanthifolia, P. subnuda
Web links	Local floras: CA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog. WildflowerSearch iNaturalist (observations) LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Packera breweri

Packera

ragwort

Habit

Herbs annual, biennial, or perennial, 3–100+ cm; caudices rhizomatous or taprooted, often with thin, branched, fibrous roots.

Stems

single or clustered; erect, glabrous or pubescent.

Leaves

alternate;

basal and cauline;

blades elliptic, lanceolate, linear, lyrate, orbiculate; ovate, reniform, or spatulate, often pinnately lobed to pinnatifid or pinnatisect;

margins entire or crenate, dentate, or serrate to denticulate, pinnately veined;

cauline much reduced; upper leaves bract-like, petiolate or sessile.

Inflorescences

terminal heads; in compact or open corymb-, cyme-, or subumbel-like arrays, rarely heads solitary.

Involucres

campanulate to cylindric.

Receptacles

flat;

paleae 0.

Ray florets

0 or 5–13, pistillate, fertile, pale yellow to orange-red.

Disc florets

20–80+; bisexual, fertile;

corollas pale yellow to orange-red;

tubes ? campanulate;

lobes 5; erect to recurved, usually ± deltate;

style branch tips usually truncate.

Phyllaries

persistent, 8, 13, or 21 in 1 series.

Calyculi

0 or 1–5+ bractlets.

Fruits

cylindric, tan to dark brown, glabrous or pubescent;

ribs usually 5–10, pappi of white, barbellulate bristles.

Heads

radiate or discoid.

Packera breweri

Packera

Distribution

[WildflowerSearch map]

[BONAP county map]

Discussion

North America. 66 species; 10 species treated in Flora.

Packera is a segregate of Senecio. It contains species that were traditionally referred to as “aureoid senecios,” an informal group that was first recognized by Asa Gray. Base chromosome numbers of x=22 or 23 (as opposed to x=10) and a suite of morphological characters have traditionally been used in the circumscription of the genus. More recent molecular and palynological studies lend good support for the recognition of the genus. Species boundaries in the genus are notoriously imprecise, and polyploidy is common. Some species hybridize to some extent with others whenever they come into contact, while others are never known to hybridize. Authors of some studies on the more widespread species propose dividing the species into many varieties based on subtle differences in vegetative morphology, which are often overlapping and inconsistent, and on populational differences due to polyploidy. While recognizing the value of such work in understanding evolutionary relationships, I have taken the view that splitting these species into many varieties based on these difficult characters does little to help with their identification in the field, and these proposed varieties are not supported by molecular data.

Source

Flora of Oregon, volume 2, page 320
Debra Trock

Sibling taxa