OregonFlora: Pseudognaphalium thermale vs. Pseudognaphalium luteoalbum

	Pseudognaphalium thermale	Pseudognaphalium luteoalbum
	northwestern rabbit-tobacco, Wright's cudweed	weedy cudweed
Habit	Plants perennial, 2–9 dm.	Plants annual, 1.5–4 dm.
Stems	floccose-tomentose, not glandular.	floccose-tomentose, not glandular.
Leaves	1.5–9 cm, linear to oblanceolate to narrowly oblong, bases decurrent on stem, not clasping; surfaces floccose-tomentose, sometimes minutely glandular beneath longer trichomes.	1.5–5 cm, broadly or narrowly linear to oblanceolate, bases clasping, not decurrent; surfaces floccose-tomentose, not glandular.
Involucres	4–6 mm.	3–4 mm.
Phyllaries	in 3–4 series, white; surfaces glabrous.	in 3–4 series, green or brownish; surfaces glabrous.
Fruits	0.5–0.6 mm, brown; pappi white.	0.3–0.5 mm, brown; pappi white.
Outer florets	35–55; corolla tips yellow.	130–160; corolla tips red.
Inner florets	4–7.	5–10.
2n		=14, 16, 28.

	Pseudognaphalium thermale	Pseudognaphalium luteoalbum
Distribution	[WildflowerSearch map]	[WildflowerSearch map]
Discussion	Conifer forests, shrublands, grasslands, riverbanks, lakesides, dry slopes, roadsides, disturbed areas. Flowering Jun–Oct. 0–2000 m. BW, Casc, CR, ECas, Sisk. CA, ID, NV, WA; north to British Columbia, northeast to Alberta, east to WY, southeast to UT. Native. Pseudognaphalium thermale is here recognized at the species rank rather than its earlier placement as a subspecies of P. canescens or a variety of P. microcephalum.	Riverbanks, roadsides, disturbed areas. Flowering May–Aug. 0–300 m. CR, Est, Sisk, WV. CA, NV, WA; southeast to FL, south to Mexico; Africa, Asia, Australia, Europe, Pacific Islands. Exotic.
Source	Flora of Oregon, volume 2, page 327 Kenton Chambers	Flora of Oregon, volume 2, page 327 Kenton Chambers
Sibling taxa	P. californicum, P. luteoalbum, P. macounii, P. stramineum	P. californicum, P. macounii, P. stramineum, P. thermale
Synonyms	Gnaphalium canescens ssp. thermale, Gnaphalium microcephalum, Gnaphalium microcephalum var. thermale, Gnaphalium thermale
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC, CA, OR, WA 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

Pseudognaphalium luteoalbum

northwestern rabbit-tobacco, Wright's cudweed

weedy cudweed

Habit

Plants perennial, 2–9 dm.

Plants annual, 1.5–4 dm.

Stems

floccose-tomentose, not glandular.

Leaves

1.5–9 cm, linear to oblanceolate to narrowly oblong, bases decurrent on stem, not clasping;

surfaces floccose-tomentose, sometimes minutely glandular beneath longer trichomes.

1.5–5 cm, broadly or narrowly linear to oblanceolate, bases clasping, not decurrent;

surfaces floccose-tomentose, not glandular.

Involucres

4–6 mm.

3–4 mm.

Phyllaries

in 3–4 series, white;

surfaces glabrous.

in 3–4 series, green or brownish;

surfaces glabrous.

Fruits

0.5–0.6 mm, brown;

pappi white.

0.3–0.5 mm, brown;

pappi white.

Outer florets

35–55;

corolla tips yellow.

130–160;

corolla tips red.

Inner florets

4–7.

5–10.

=14, 16, 28.

Pseudognaphalium luteoalbum

Distribution

[WildflowerSearch map]

Discussion

Conifer forests, shrublands, grasslands, riverbanks, lakesides, dry slopes, roadsides, disturbed areas. Flowering Jun–Oct. 0–2000 m. BW, Casc, CR, ECas, Sisk. CA, ID, NV, WA; north to British Columbia, northeast to Alberta, east to WY, southeast to UT. Native.

Pseudognaphalium thermale is here recognized at the species rank rather than its earlier placement as a subspecies of P. canescens or a variety of P. microcephalum.

Riverbanks, roadsides, disturbed areas. Flowering May–Aug. 0–300 m. CR, Est, Sisk, WV. CA, NV, WA; southeast to FL, south to Mexico; Africa, Asia, Australia, Europe, Pacific Islands. Exotic.

Source

Flora of Oregon, volume 2, page 327
Kenton Chambers

Sibling taxa

P. californicum, P. luteoalbum, P. macounii, P. stramineum

P. californicum, P. macounii, P. stramineum, P. thermale

Synonyms

Gnaphalium canescens ssp. thermale, Gnaphalium microcephalum, Gnaphalium microcephalum var. thermale, Gnaphalium thermale

Web links