Ivesia sericoleuca
Ivesia jaegeri
Plumas ivesia, Plumas mousetail
Jaeger's ivesia, Jaeger's mousetail
decumbent to ascending, 1.5–4.5 dm.
pendent or prostrate to ascending, 0.3–1.5 dm.
10–20(–30) cm; sheathing base densely strigose abaxially;
stipules absent;
petiole 2–6(–10) cm, hairs abundant, usually spreading, 1–4 mm;
leaflets 20–35 per side, loosely overlapping, 3–15 mm, lobes 0–4, oblanceolate to elliptic, hairs abundant, spreading to ascending, (0.5–)1–3(–4) mm.
± loosely cylindric to weakly planar, 2–8(–10) cm; sheathing base not or sparsely strigose abaxially;
petiole 0.5–4 cm;
lateral leaflets (1–)4–6(–8) per side, ± overlapping at least distally, ± flabellate, 2–6(–7) mm, incised nearly to base into 3–6 oblanceolate to narrowly obovate lobes, apex not or scarcely setose, surfaces ± sparsely short-pilose, ± glandular;
terminal leaflets indistinct.
3–8(–10).
(1–)2;
blade well developed.
20–120-flowered, (2–)4–14 cm diam., flowers mostly arranged in several to many tight glomerules of 5–10 flowers.
(1–)3–15-flowered, open, (0.5–)1.5–4(–7) cm diam.
1–3(–12) mm.
5–30 mm.
10–15 mm diam.;
epicalyx bractlets narrowly lanceolate to narrowly elliptic, (1.5–)2–2.5(–3) mm;
hypanthium campanulate to shallowly turbinate, 1.5–3 × 2.5–4.5(–5) mm, often nearly as deep as wide;
sepals sometimes purple-suffused, 3–5.5 mm, acute to acuminate;
petals white, broadly spatulate to broadly obovate or obcordate, 4–7 mm;
stamens 20, filaments filiform, 1.5–3 mm, anthers white to cream, 0.5–0.7 mm;
carpels 2–7, styles 2.5–4 mm.
5–11 mm diam.;
epicalyx bractlets 5, lanceolate, 1–2 mm;
hypanthium patelliform, 1 × 2–4 mm;
sepals 2–3 mm, ± acute;
petals yellow, narrowly oblanceolate, 1.5–2 mm;
stamens 20, filaments 1–1.5(–1.8) mm, anthers yellow, subrotund, 0.2–0.3 mm;
carpels 3–8, styles 1.5–2 mm.
brown, 2–3 mm.
tan to light brown, 1–2 mm, ± rugose, ± carunculate.
= 28.
Ivesia sericoleuca
Ivesia jaegeri
Of conservation concern.
Ivesia sericoleuca is known from valleys and flats in the northern Sierra Nevada. Many historic collections were identified and distributed as I. unguiculata, and circumscriptions prior to 1962 include I. aperta (hence reports from Nevada).
Hairs are usually dense in plants of Ivesia sericoleuca, such that the leaves, and occasionally the stems and branches, are silvery gray, especially in Sierra Valley and the Feather River drainage. Plants in the Truckee River drainage tend to be less hairy with redder stems, less glomerate inflorescences, shallower hypanthia, and more conspicuous glandularity.
As mentioned by J. T. Howell (1962), the chromosome count given for Ivesia sericoleuca by P. A. Munz (1959) most likely was based on a collection of I. aperta var. aperta. The chromosome count given here is instead based on Kruckeberg 3665, originally distributed as I. pickeringii.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Of conservation concern.
Ivesia jaegeri is known only from the Spring Mountains, Clark County, Nevada, and the Clark Mountains, San Bernardino County, California.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
WildflowerSearch
iNaturalist
USDA Plants Database
