Ivesia paniculata
Ivesia aperta
Ash Creek ivesia, Ash Creek mousetail
Sierra Valley ivesia, Sierra Valley mousetail
± prostrate, 0.4–1.5(–2) dm.
decumbent to erect, 1.5–4.5 dm.
tightly cylindric, (1.5–)2–5(–7) cm; sheathing base densely hairy abaxially;
petiole 0.5–4 cm;
lateral leaflets (5–)8–15 per side, overlapping at least distally, ± flabellate, 0.5–2 mm, incised to base or nearly so into (0–)3–8(–15) elliptic to narrowly obovate lobes, apex not or obscurely setose, surfaces densely hirsute, cryptically 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 reduced.
3–8.
20–200-flowered, congested, (1–)1.5–6(–10) cm diam.
(10–)20–250-flowered, 1–14 cm diam., flowers arranged in several to many tight glomerules of 5–20 flowers.
1.5–6 mm.
1–3(–15) mm.
4–6 mm diam.;
epicalyx bractlets 5, lanceolate to elliptic, 0.6–1.5(–2) mm;
hypanthium shallowly cupulate, 1 × 2–3 mm;
sepals (1–)1.5–2.5(–3) mm, acute;
petals white to pale yellowish, linear, 1 mm;
stamens 5, filaments 0.3–1 mm, anthers yellow with maroon margins, ovate, 0.3–0.5 mm;
carpels 1–2(–3), styles 0.7–1.8 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.
brown, 0.8–1.5 mm, smooth, prominently carunculate.
brown, 2–3 mm.
Ivesia paniculata
Ivesia aperta
Of conservation concern.
Ivesia paniculata is known only from the Ash Valley area of Lassen County. The distinctions between I. paniculata and I. rhypara are perhaps on the same scale as variation among disjunct population clusters of I. rhypara, but no taxonomic adjustments are proposed at this time.
(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 |
CA
WildflowerSearch
iNaturalist
USDA Plants Database
