Ivesia tweedyi
Ivesia campestris
Tweedy's ivesia, Tweedy's mousetail
field ivesia, field mousetail, Kaweah ivesia
ascending to erect, 0.4–2(–3.5) dm.
decumbent to ascending, 1–3.5 dm.
loosely cylindric, (3–)4–12(–17) cm; sheathing base glabrous abaxially;
petiole 0.5–7 cm, hairs 1–1.5 mm;
leaflets 10–16 per side, 4–7(–10) mm, glabrous or sparsely hirsute, glandular-puberulent or -pubescent, lobes (2–)5–15, linear to narrowly oblanceolate, apex not setose.
(3–)5–15(–18) cm; sheathing base glabrous or sparsely strigose abaxially;
stipules ± lanceolate, 2.5–5 mm;
petiole (0.3–)0.5–6(–8) cm, hairs sparse to abundant, appressed-ascending, 1–2 mm;
leaflets 15–20 per side, loosely overlapping, 2–10 mm, lobes 2–5, oblanceolate, hairs sparse to abundant, spreading to ascending, 1–2 mm.
(0–)1–2, not paired.
3–4.
(5–)10–25(–35)-flowered, (1–)1.5–3(–4.5) cm diam.;
glomerules 1–few.
5–20(–40)-flowered, (1–)1.5–2.5(–4) cm diam., flowers arranged in 1–few ± tight glomerules of 10–15 flowers.
1–3(–5) mm.
1–4 mm.
9–12 mm diam.;
epicalyx bractlets linear, 1–2 mm;
hypanthium shallowly campanulate, 1–1.5 × 2–4(–5.5) mm;
sepals 2–3.5 mm, acute;
petals golden yellow, broadly elliptic to spatulate, 2.5–3.3 mm;
stamens 5, filaments 1–1.7 mm, anthers yellow, 0.5–0.8 mm;
carpels (2–)4–6(–9), styles 2–3 mm.
7–10 mm diam.;
epicalyx bractlets linear to oblong, 1–2(–2.5) mm;
hypanthium campanulate, 1–2 × 2.5–4 mm, ± 1/2 as deep as wide;
sepals green, 2–3(–3.5) mm, acute;
petals 4(–5), light yellow, oblanceolate to spatulate or narrowly obovate, 3–4 mm;
stamens 12–16 (4-merous flowers) or 16–20 (5-merous flowers), filaments filiform, 0.6–1.1 mm, anthers yellowish, 0.3–0.5 mm;
carpels 4–20, styles 1.4–2 mm.
olive green, 1.8–2 mm.
light brown, 1–1.5 mm.
Ivesia tweedyi
Ivesia campestris
Of conservation concern.
Ivesia tweedyi is found from the Cascade Range in Washington to Boundary and Shoshone counties in Idaho, barely entering Montana in Mineral County.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Ivesia campestris is found in the southern Sierra Nevada south of the Kings River, where it replaces I. unguiculata and often occurs at higher elevations.
Ivesia campestris is the only member of the genus that commonly has 4-merous flowers. It is sometimes misidentified as I. unguiculata, especially when the pale yellow petals have faded to creamy white; the glomerules of the inflorescences tend to be yellowish green to green rather than purplish. Also, the anthers of I. campestris are yellowish, rather than maroon.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
WA
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
CA
