Eriogonum umbellatum var. dumosum

(Greene) Reveal

Harvard Pap. Bot. 9: 202. 2004.

Common names: American Valley sulphur flower
Endemic
Basionym: Eriogonum dumosum Greene Pittonia 3: 199. 1897
Synonyms: Eriogonum umbellatum subsp. dumosum (Greene) S. Stokes
Treatment appears in FNA Volume 5. Treatment on page 343. Mentioned on page 338, 352.

Shrubs, round to erect, 3–5 × 3–10 dm. Aerial flowering-stems erect, 0.8–2 (–2.5) dm, tomentose to floccose, without one or more leaflike bracts ca. midlength. Leaves in loose rosettes; blade elliptic to ovate, 1–2.5 (–3) × 0.5–1.2 cm, densely tomentose abaxially, thinly floccose or glabrous adaxially, margins plane. Inflorescences umbellate; branches 2–6 (–10) cm, tomentose to floccose, without a whorl of bracts ca. midlength; involucral tubes 2–3 (–5) mm, lobes 2.5–4 mm. Flowers 5–9 mm; perianth bright-yellow.


Phenology: Flowering Jun–Sep.
Habitat: Sandy to gravelly flats and slopes, mixed grassland communities, oak and conifer woodlands
Elevation: (300-)600-1200 m

Discussion

Variety dumosum has been called var. polyanthum in the recent California literature. It is known only from widely scattered locations, where it is localized and typically infrequent, in Amador, Placer, Plumas, Shasta, and Siskiyou counties in California, and just inside Oregon (in Jackson County). It approaches var. nevadense in size but differs in having much more densely tomentose leaf blades. It can be confused also with var. modocense, which is much smaller and nearly always to the east or north of var. dumosum. Unlike the related var. ahartii, which is always on serpentine soils, var. dumosum is only occasionally found on that substrate. The American Valley sulphur flower is a largish shrub that is ideal for the garden and may well prove popular if successfully cultivated.

Selected References

None.

Lower Taxa

None.

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light-brown;brown +
included +  and exserted +
3-gonous +
usually red +  and cream or yellow +
oblong +  and ellipsoid or oval +
James L. Reveal +
(Greene) Reveal +
deciduous +  and persistent +
stipelike +
0.13 cm1.3 mm <br />0.0013 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
Eriogonum dumosum +
awn-tipped +  and simple +
2.5 cm25 mm <br />0.025 m <br /> (3 cm30 mm <br />0.03 m <br />) +
1 cm10 mm <br />0.01 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
glabrous +, floccose +  and tomentose +
elliptic;ovate +
0.5 cm5 mm <br />0.005 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
not awn-tipped +
0.1 cm1 mm <br />0.001 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
midlength +
glandular +, pubescent +  and glabrous +
3;several +
scale-like +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
grooved +, disarticulating +  and dichotomous +
6 cm60 mm <br />0.06 m <br /> (10 cm100 mm <br />0.1 m <br />) +
not brittle +
tomentose +  and floccose +
scabrellous +
2 cm20 mm <br />0.02 m <br /> (6 cm60 mm <br />0.06 m <br />) +
spreading +  and erect +
whorled +, opposite +  and alternate +
American Valley sulphur flower +
Calif. +  and Oreg. +
(300-)600-1200 m +
curved +  and straight +
1 cm10 mm <br />0.01 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
unisexual +  and bisexual +
attenuate +
0.5 cm5 mm <br />0.005 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
decumbent to erect +  and prostrate +
not fistulose +
unwinged +  and winged +
black +, red +, brown +  and yellowish +
exserted +  and included +
pubescent +  and glabrous +
spheroidal +, 4-gonous +, lenticular +, biconvex +, discoid +, 3-gonous +  and 2-gonous +
Sandy to gravelly flats and slopes, mixed grassland communities, oak and conifer woodlands +
capitate +  and subcapitate +
3 cm30 mm <br />0.03 m <br /> (25 cm250 mm <br />0.25 m <br />) +
cymelike +, paniclelike +, racemelike +  and spikelike +
2 cm20 mm <br />0.02 m <br /> (18 cm180 mm <br />0.18 m <br />) +
connate +  and free +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
tomentose +  and thinly floccose or glabrous +
turbinate +  and campanulate +
nonmembranous +
0.15 cm1.5 mm <br />0.0015 m <br /> (1 cm10 mm <br />0.01 m <br />) +
in whorls +, opposite +, alternate +  and rosulate +
persistent +
cauline +  and basal +
bractlike +
pubescent +  and glabrous +
not swollen +
orthotropous +
accrescent +
curved +  and straight +
erect to deflexed +
bright-yellow +
cylindric +  and urceolate +
accrescent +
fleshy +, indurate +  and membranous +
with extrafloral nectaries +  and not articulate +
3 cm30 mm <br />0.03 m <br /> (4 cm40 mm <br />0.04 m <br />) +
mostly tomentose +  and floccose or glabrous +
0.1 cm1 mm <br />0.001 m <br /> (3 cm30 mm <br />0.03 m <br />) +
Flowering Jun–Sep. +
homostylous +  and 3-carpellate +
0.3 cm3 mm <br />0.003 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (1.8 cm18 mm <br />0.018 m <br />) +
Harvard Pap. Bot. +
, +  and solid +
slender;stout +
persistent +
0.2 cm2 mm <br />0.002 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
decumbent to erect +  and prostrate +
prostrate +  and erect +
glandular +, pubescent +  and glabrous +
penicillate +, fimbriate +  and capitate +
deciduous +  and persistent +
2-lobed +  and cylindric +
coriaceous +  and membranous +
consisting of a series +  and tubular +
distinct +
erect;spreading or recurved +
spreading;erect +
Eriogonum umbellatum subsp. dumosum +
chambered +  and solid +
slender +  and stout +
Eriogonum umbellatum var. dumosum +
Eriogonum umbellatum +
variety +
emarginate +  and entire +
1/4 +  and 1/3 +
usually spatulate +  and obovate +
coriaceous +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
involucral +
persistent +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
membranous +
pubescent +  and glabrous +
sericeous +, lanate +  and tomentose floccose or glabrous +
dioecious +, polygamodioecious +, synoecious +  and polycarpic +
annual +, biennial +  and perennial +
tomentose +  and glabrous +
midlength +
3 +, 2 +  and 1 +