Ivesia gordonii var. ursinorum

(Jepson) Ertter & Reveal

Novon 17: 323. 2007.

Common names: Spider ivesia
Endemic
Basionym: Potentilla gordonii var. ursinorum Jepson Man. Fl. Pl. Calif., 492. 1925
Treatment appears in FNA Volume 9. Treatment on page 235. Mentioned on page 234.

Stems usually dark reddish, usually prostrate to ascending, rarely nearly erect, (0.2–) 0.5–1.5 (–2.5) dm, usually not villous or hirsute, minutely glandular or glandular-puberulent to pubescent. Basal leaves (1–) 3–8 (–15) × 0.3–0.8 cm; leaflets 1–4 (–6) mm, glabrous or sparsely hirsute, at least marginally, rarely more densely hirsute. Inflorescences 5–20 (–25) -flowered, usually simple, 1–2 (–5) cm diam., glomerules usually 1, capitate to loosely congested. Flowers 6–9 mm diam.; epicalyx bractlets (0.5–) 1.5–2 (–3) mm; hypanthium (1.5–) 2–3 (–4) × 2–3 (–4) mm; sepals (2–) 2.5–4 (–4.5) mm, acute; anthers usually red-margined.


Phenology: Flowering summer.
Habitat: Rocky slopes and outcrops, in high-elevation sagebrush communities, montane conifer woodlands
Elevation: 1800–3500 m

Distribution

V9 360-distribution-map.jpg

Calif., Idaho, Nev., Oreg.

Discussion

As circumscribed here, var. ursinorum encompasses “tenuicaulis” of N. H. Holmgren (1997b) but is more broadly defined to encompass generally prostrate to decumbent plants found at widely scattered locations in and adjacent to the northwestern Intermountain Region. Such plants are most common in the Independence and Jarbidge mountains (Elko County, Nevada) and on Steens Mountain and other ranges in southeastern Oregon. Similar plants dominate the mountains of central Idaho and the Wallowa Mountains of Oregon, mostly south of var. alpicola. In northern California, var. ursinorum is found on the Modoc, Scott, and Sweetwater mountains, and around Sonora Pass in the Sierra Nevada.

In general, var. ursinorum may be distinguished from var. alpicola by its more commonly prostrate to ascending habit, reddish stems, narrowly cylindric (bottlebrushlike) leaves, and rounder leaflet lobes. The inflorescence is also more prone to becoming lax at maturity. Plants are most often glandular-pubescent and minutely glandular but otherwise glabrate, the conspicuous exception being the type of var. ursinorum from northern California. Plants in the Wallowa Mountains approach var. alpicola, as do some populations in California and central Idaho, where they are sometimes only tentatively assigned to one variety or the other. Some central Idaho collections included here in var. ursinorum have more cupulate hypanthia and wider petals approaching those of Ivesia lycopodioides.

Selected References

None.

Lower Taxa

None.

"dm" is not declared as a valid unit of measurement for this property.

not carunculate +
grayish brown +  and mottled brown +
longer than wide +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
Barbara Ertter +  and James L. Reveal +
(Jepson) Ertter & Reveal +
compound +  and simple +
opposite +  and alternate +
8 cm80 mm <br />0.08 m <br /> (15 cm150 mm <br />0.15 m <br />) +
20 cm200 mm <br />0.2 m <br /> (25 cm250 mm <br />0.25 m <br />) +
3 cm30 mm <br />0.03 m <br /> (8 cm80 mm <br />0.08 m <br />) +
3 cm30 mm <br />0.03 m <br /> (20 cm200 mm <br />0.2 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
Potentilla gordonii var. ursinorum +
20 cm200 mm <br />0.2 m <br /> (25 cm250 mm <br />0.25 m <br />) +
narrowly oblong +  and filiform planar +
reduced +
0.5 cm5 mm <br />0.005 m <br /> (20 cm200 mm <br />0.2 m <br />) +
reduced +
elongate +
free +  and distinct +
branched +  and simple +
Spider ivesia +
Calif. +, Idaho +, Nev. +  and Oreg. +
not +  and aggregated +
1800–3500 m +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
0.13 cm1.3 mm <br />0.0013 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
0.6 cm6 mm <br />0.006 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
unisexual +  and bisexual +
not +  and aggregated +
deciduous +
obliquely ovoid +  and reniform +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
capitate +  and loosely congested +
Rocky slopes and outcrops, in high-elevation sagebrush communities, montane conifer woodlands +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
simple +  and 5-20(-25)-flowered +
1 cm10 mm <br />0.01 m <br /> (2 cm20 mm <br />0.02 m <br />) +
crassinucellate +
opposite +  and alternate +
winter-marcescent +
deciduous +  and persistent +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
, +  and distinct +
not +  and distinguishable +
hirsute +  and glabrous +
0.1 cm1 mm <br />0.001 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
narrowly oblanceolate +  and obovate +
verticillate +
toothed +, unlobed +  and lobed +
inferior +  and superior +
clustered +, biseriate +  and superposed +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0 (?) +  and 4 (?) +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
free +  and distinct +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (8 cm80 mm <br />0.08 m <br />) +
Flowering summer. +
adnate +, free +, connate +  and distinct +
not arillate +
0.4 cm4 mm <br />0.004 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
persistent +
free +  and distinct +
erect +  and spreading +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
free +  and distinct +
branched +  and simple +
dark reddish +
erect +, usually prostrate +  and ascending +
2 +  and 20 +
palmate +  and pinnate +
0.45 cm4.5 mm <br />0.0045 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
deciduous +
distinct +
subterminal +
filiform +
rough-thickened +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
Potentilla gordonii +
not fleshy +
Ivesia gordonii var. ursinorum +
Ivesia gordonii +
variety +
inconspicuous +
stipelike +, elongate +, less flat +  and conic or turbinate +
enlarged +
glabrate +  and sparsely densely glandular-puberulent +