FNA: Psilocarphus oregonus vs. Psilocarphus

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

CA; ID; NV; OR; WA

[WildflowerSearch map]

[BONAP county map]

w North America; nw Mexico; Amphitropical; s South America

[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.)

Species 5 (5 in the flora).

See discussion of Filagininae following the tribal description (p. 385).

In the flora area, Psilocarphus inhabits sites with Mediterranean, semiarid, and cool-temperate climates. In the south, it remains within the Californian Floristic Province, not entering the Mojave and Sonoran deserts; to the north, it extends from the Pacific Northwest eastward across the Great Basin, Columbia Plateau, and northern Rocky Mountains to the western edge of the northern Great Plains. Ongoing degradation of vernal pool habitats in California may soon justify conservation concern for P. chilensis and P. brevissimus var. multiflorus.

The amphitropical species of Psilocarphus and Micropsis (P. brevissimus var. brevissimus, P. chilensis, M. dasycarpa) occupy littoral habitats; migratory shorebirds probably facilitate occasional long-distance dispersal of their light cypsela-palea complexes (A. Cronquist 1950). Populations of these self-pollinating species can establish from one cypsela.

Psilocarphus is monophyletic and probably sister to Micropus, with ancestors in or near Stylocline (J. D. Morefield 1992). Psilocarphus is easily recognized by leaves opposite and paleae cucullate or galeate, reticulately nerved; the clusters of heads resemble compact bunches of woolly grapes or marbles. Differences between species are slight but consistent in most specimens.

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

Key

1. Largest heads 6–14 mm; pistillate paleae collectively hidden by indument and/or longest 2.8–4 mm	→ 2
1. Largest heads mostly 3–6 mm; pistillate paleae usually individually visible through indument, longest mostly 1.5–2.7 mm	→ 4
2. Heads ± ovoid, largest 9–14 mm; receptacles deeply lobed; pistillate paleae ± cylindric, lengths mostly 3.5–6 times longest diams. (wings ± median)	P. brevissimus
2. 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)	→ 3
3. Capitular leaves mostly lanceolate to ovate, widest in proximal 2/3, longest mostly 8–15 mm, lengths mostly 1.5–4 times widths; plants usually densely lanuginose; cypselae narrowly obovoid	P. brevissimus
3. Capitular leaves mostly oblanceolate to nearly linear, widest in distal 1/3, longest mostly 17–35 mm, lengths mostly 4.5–9 times widths; plants ± sericeous; cypselae ± cylindric	P. elatior
4. Capitular leaves linear to narrowly oblanceolate, lengths mostly 6–12 times widths, (3–) 3.5–5 times head heights; cypselae ± cylindric	P. oregonus
4. Capitular leaves mostly spatulate to obovate or ovate, lengths mostly 1.2–5 times widths, 1–2.5(–3) times head heights; cypselae ± obovoid	→ 5
5. Capitular leaves mostly not appressed to heads, spatulate to obovate, lengths mostly 2–5 widths; proximal internode lengths mostly 1–2(–3) times leaf lengths; staminate corolla lobes mostly 5	P. tenellus
5. Capitular leaves appressed to heads, ovate to broadly elliptic, lengths mostly 1.2–1.8(–2) times widths; proximal internode lengths (2–)3–6 times leaf lengths; staminate corolla lobes mostly 4	P. chilensis