Ivesia setosa
Ivesia aperta
bristly ivesia
Sierra Valley ivesia, Sierra Valley mousetail
± ascending to nearly erect, 0.7–2.5(–2.8) dm.
decumbent to erect, 1.5–4.5 dm.
weakly planar to loosely cylindric, 5–9(–12) cm; sheathing base ± strigose abaxially;
petiole 1–8 cm;
lateral leaflets 5–10 per side, separate to overlapping distally, ± flabellate, 2–8 mm, incised ± 3/4 to base, sometimes nearly to base, into (3–)7–11 ovate teeth to narrowly obovate lobes, apex usually ± setose, surfaces ± sparsely hirsute, conspicuously glandular;
terminal leaflets ± indistinct.
(7–)10–20(–23) cm; sheathing base densely strigose abaxially;
stipules absent;
petiole 4–8 cm, hairs abundant, ascending, ± 1(–3) mm;
leaflets 20–35 per side, loosely overlapping, 3–15(–20) mm, lobes 0–4(–5), oblanceolate to elliptic, hairs abundant, ascending to appressed, ± 1(–2) mm.
(0–)1;
blade vestigial.
3–8.
(1–)5–15(–30)-flowered, ± open, 1–6(–12) cm diam.
(10–)20–250-flowered, 1–14 cm diam., flowers arranged in several to many tight glomerules of 5–20 flowers.
5–15(–20) mm.
1–3(–15) mm.
7–10 mm diam.;
epicalyx bractlets 5, lanceolate, 1.3–2.5(–3) mm;
hypanthium patelliform, (1–)1.5–2 × 2–3.5(–4) mm;
sepals (1.5–)2–3.5 mm, ± acute;
petals yellow, oblanceolate to narrowly spatulate, 1.5–2.5 mm;
stamens 5, filaments 0.8–1.5 mm, anthers yellow, oblong, 0.4–0.7 mm;
carpels 2–8, styles 1.2–2 mm.
5–12 mm diam.;
epicalyx bractlets lanceolate, 1.5–2.5(–3.5) mm;
hypanthium cupulate, 1–2 × 2.5–4(–5) mm, 1/2–2/3 as deep as wide;
sepals green, 2.5–4(–5.5) mm, acute to acuminate;
petals light yellow, oblanceolate to broadly obovate, 2–7 mm;
stamens 20, filaments filiform, 1–4 mm, anthers yellow, 0.4–0.6 mm;
carpels 2–7, styles 2–4 mm.
greenish white to light tan, 1.7–2 mm, smooth, ± carunculate.
brown, 2–3 mm.
Ivesia setosa
Ivesia aperta
Ivesia setosa occurs mostly to the east and south of I. baileyi, from southeastern Humboldt and Churchill counties to Elko, White Pine, and northern Nye counties, Nevada, and in the Deep Creek Range of western Utah. It represents a transition between the planar-leaved, chasmophytic members of sect. Setosae and the cylindric-leaved, matted species of flatter sites. Stems of I. setosa are more generally erect than in other species in the section, and the usually calcareous substrate is noteworthy. The deeply incised (usually not quite to base) leaflets are somewhat intermediate between the toothed leaflets of I. baileyi and the leaflets of I. shockleyi that are incised to the base into separate lobes. The individual leaflets of both I. baileyi and I. setosa are more or less flat and distichously paired; in I. shockleyi, groups of leaflet lobes are folded over onto each other, giving a verticillate appearance to the leaflet arrangement.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Varieties 2 (2 in the flora).
Many historic collections of Ivesia aperta were identified as I. pickeringii. D. D. Keck (1938) considered I. aperta to be no more than a yellow-flowered form of I. sericoleuca, a situation clarified and rectified by J. T. Howell (1962). The ranges of the two species overlap in Sierra Valley, California, with mixed populations occurring near Beckwourth and in the valleys north of Sierra Valley. In general, var. aperta occurs in the southeastern portions of the valley and I. sericoleuca occurs on the western side; the species are not otherwise sympatric. In addition to petal color, which fades in herbarium material, I. aperta differs from I. sericoleuca in having smaller flowers with shallower hypanthia. Hairs at the base of the stems and petioles of I. aperta are relatively short (to 2 mm) and generally ascending; those of I. sericoleuca are longer (to 4 mm) and spreading. Variety canina combines the petal color of var. aperta and floral dimensions of I. sericoleuca.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Petals 2–3 mm, oblanceolate; filaments 1–1.5(–2) mm; Sierra Valley drainage, California, Carson and Virginia ranges, Nevada. | var. aperta |
1. Petals usually 4–7 mm, narrowly to broadly obovate; filaments 2–4 mm; Dog Valley, California, Nevada. | var. canina |
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USDA Plants Database
