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Oregon woolly marbles, Oregon woolly-heads, Oregon woollyheads or woolly marbles, woolly marbles

dwarf woolly-heads, dwarf woolly-marbles, Robbin's pondweed, short woollyheads, woolly marbles

Habit Plants silvery to whitish, densely sericeous to somewhat lanuginose. Plants greenish to grayish, sericeous to densely lanuginose.
Stems

(1–)2–10, ascending to ± prostrate;

proximal internode lengths mostly 0.5–1.5(–2) times leaf lengths.

(1–)2–10, erect to prostrate;

proximal internode lengths mostly 0.5–1.5(–2) times leaf lengths.

Receptacles

unlobed.

unlobed or ± lobed.

Heads

± spheric, largest 4–6 mm.

± spheric, rarely ovoid, largest 6–14 mm.

Cypselae

narrowly ± cylindric, terete, 0.6–1.2 mm.

narrowly obovoid, ± compressed, 0.8–1.9 mm.

Capitular

leaves ± erect, appressed to heads, linear to narrowly oblanceolate, widest in distal 2/3, longest 12–20 mm, lengths mostly 6–12 times widths, (3–)3.5–5 times head heights.

leaves ± erect, appressed to heads (sometimes spreading), linear-lanceolate to ovate, widest in proximal 2/3, longest 8–25 mm, lengths mostly 1.5–6 times widths, 1–2.5(–3) times head heights.

Pistillate

paleae individually visible through indument, longest mostly 1.5–2.7 mm.

paleae hidden by or visible through indument, longest 2.8–4 mm (lengths 1.5–6 times longest diams.; wings subapical to ± median).

Staminate

corollas 0.7–1.4 mm, lobes mostly 4.

corollas 0.8–1.6 mm, lobes mostly 5.

2n

= 28.

Psilocarphus oregonus

Psilocarphus brevissimus

Phenology Flowering and fruiting late Mar–mid Aug.
Habitat Seasonally inundated or flooded clay soils (vernal pool margins, drainages, moist rocky slopes)
Elevation 10–1800(–2400) m (0–5900(–7900) ft)
Distribution
from FNA
CA; ID; NV; OR; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; ID; MT; NV; OR; UT; WA; WY; AB; BC; SK; s South America
[WildflowerSearch map]
[BONAP county map]
Discussion

Psilocarphus oregonus occurs from west-central California through most of Oregon to southeastern Washington, western Idaho, and northern Nevada. Relatively narrow-leaved, montane forms of P. tenellus account for reports of P. oregonus from the southern Sierra Nevada to Baja California; further study may show these to be intermediates between the two taxa.

A malformed plant collected in Merced County, California, appears to have been a sterile hybrid between P. oregonus and Hesperevax caulescens (J. D. Morefield 1992c).

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

Varieties 2 (2 in the flora).

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

Key
1. Heads ± spheric, largest 6–9 mm, receptacles unlobed or shallowly lobed; pistillate paleae obovoid, lengths 1.5–3 times longest diams., wings supramedian to subapical
var. brevissimus
1. Heads ovoid, largest 9–14 mm, receptacles deeply lobed; pistillate paleae ± cylindric, lengths mostly 3.5–6 times longest diams., wings ± median
var. multiflorus
Source FNA vol. 19, p. 459. FNA vol. 19, p. 458.
Parent taxa Asteraceae > tribe Gnaphalieae > Psilocarphus Asteraceae > tribe Gnaphalieae > Psilocarphus
Sibling taxa
P. brevissimus, P. chilensis, P. elatior, P. tenellus
P. chilensis, P. elatior, P. oregonus, P. tenellus
Subordinate taxa
P. brevissimus var. brevissimus, P. brevissimus var. multiflorus
Name authority Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 341. (1840) Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 340. (1840)
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