Micropus amphibolus

A. Gray

Proc. Amer. Acad. Arts 17: 214. 1882.

Common names: Mount Diablo cottonseed
IllustratedEndemic
Synonyms: Stylocline amphibola (A. Gray) J. T. Howell
Treatment appears in FNA Volume 19. Treatment on page 455. Mentioned on page 454, 456.

Plants 2–20 cm. Heads ± spheric, 3.5–5 mm diam. Receptacles obovoid, mostly 0.7–1 mm, heights 1.2–1.8 times diams. Pistillate paleae 8–12 in 2 series, longest 2–3 mm; wings prominent, not withering, subapical, inflexed, ± obovate, plane to concave; bodies somewhat galeate, mainly chartaceous, cartilaginous medially, ± lanuginose. Staminate paleae mostly 1–3. Staminate corollas 1.2–1.9 mm, lobes 4 (–5). Cypselae 1–1.5 mm, corolla scars in distal 1/4; pappi: staminate of 1–5, ± barbellulate bristles 1.7–2 mm.


Phenology: Flowering and fruiting late Mar–Jun.
Habitat: Slopes, ridges, on and near rock outcrops, shallow gravelly soils derived from shale, mudstone, sandstone, volcanic rocks (not recorded on serpentine), edges of or in clearings, grasslands, chaparral, woodlands
Elevation: 40–900 m

Discussion

Micropus amphibolus is relatively uncommon; it is known from mountains and hills of the San Francisco Bay area and northern Coast Ranges, plus populations in outer southern Coast Ranges and in foothills of the northern Sierra Nevada. It is superficially similar to and often confused with M. californicus (see discussion there). Relatively few recent collections of M. amphibolus are known, raising significant conservation concerns.

Though consistently distinct, Micropus amphibolus combines some character states of Stylocline and Micropus (J. T. Howell 1948), suggesting that it may have descended from a hybrid between, or common ancestor of, the two genera. The best available morphologic evidence consistently places it basal within Micropus, with which it shares a majority of character states (J. D. Morefield 1992).

Selected References

None.

Lower Taxa

None.

"lanuginose" is not a number.

... more about "Micropus amphibolus"
truncate-penicillate;truncate +
scarious +
mostly ovate +  and lanceovate or linear +
racemiform +, paniculiform +  and corymbiform +
indeterminate +  and determinate +
James D. Morefield +
A. Gray +
decurrent +
compound +  and simple +
narrowly oblanceolate;elliptic +
cartilaginous +  and chartaceous +
muriculate +, papillate +  and smooth +
galeate +
0.17 cm1.7 mm <br />0.0017 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
Mount Diablo cottonseed +
red-tipped +, purplish +, yellow +  and whitish +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.19 cm1.9 mm <br />0.0019 m <br />) +
gibbous +, obovoid +  and compressed +
40–900 m +
staminate +  and pistillate +
winged +  and beaked +
dispersed +
Slopes, ridges, on and near rock outcrops, shallow gravelly soils derived from shale, mudstone, sandstone, volcanic rocks (not recorded on serpentine), edges of or in clearings, grasslands, chaparral, woodlands +
racemiform +  and paniculiform +
singly +  and dichasiform +
indeterminate +
0.35 cm3.5 mm <br />0.0035 m <br /> (?) +  and 0.5 cm5 mm <br />0.005 m <br /> (?) +
homogamous +  and heterogamous +
spheric +
each +  and sessile +
inconspicuous +
sessile +  and petiolate +
rarely lanceovate +  and lanceolate +
2-carpellate +
staminate +  and pistillate +
erect +  and incurved +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
persistent +
of 1 +  and 5 bristles +
Flowering and fruiting late Mar–Jun. +
subequal +  and unequal +
Proc. Amer. Acad. Arts +
paleate +  and epaleate +
1.2-1.8 times diams +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
exalbuminous +
Illustrated +  and Endemic +
5 (?) +  and 10 (?) +
ascending +  and erect +
2 +  and 5 +
appendaged +  and truncate +
papillate +
Stylocline amphibola +
Micropus amphibolus +
Micropus +
species +
1 cm10 mm <br />0.01 m <br /> (50 cm500 mm <br />0.5 m <br />) +
not withering +
subapical +
plane +  and concave +