Ivesia pityocharis
Ivesia pygmaea
pine nut mountain mousetail, pine nut mountains ivesia
dwarf ivesia, dwarf mousetail
prostrate-decumbent to ascending, 0.5–2(–3) dm.
decumbent to erect, 0.3–1(–1.5) dm.
6–12(–15) cm; sheathing base weakly strigose abaxially;
stipules absent;
petiole (1–)1.5–2.5(–3) cm, hairs abundant, ascending to spreading, 1–4 mm;
leaflets 15–25 per side, loosely overlapping, (1.5–)2–7 mm, lobes 0–4(–6), lanceolate or oblanceolate to elliptic, hairs abundant, spreading to ascending, 1–3 mm.
tightly cylindric, (0.5–)1–8(–12) cm; sheathing base usually ± strigose abaxially;
petiole 0.5–4 cm, hairs 0.2–1 mm;
leaflets 10–15(–20) per side, 0.5–4(–5) mm, sparsely to moderately short-villous, densely glandular, lobes 3–6(–8), oblanceolate to narrowly oblong or oval, apex setose.
2–5.
(0–)1, not paired.
(7–)15–50-flowered, 2–8 cm diam., flowers arranged individually and/or in several to many loose few-flowered glomerules.
(1–)5–10-flowered, 0.8–3 cm diam.;
glomerules usually 1.
(3–)6–15(–22) mm.
1.5–8(–10) mm.
8–13 mm diam.;
epicalyx bractlets lanceolate to elliptic, 2–3 mm;
hypanthium patelliform to shallowly cupulate, 1.5–2.5 × 3–4.5 mm, ± 1/2 as deep as wide;
sepals often purple-suffused, 2.3–4(–5) mm, acute;
petals white, broadly spatulate or obovate to orbiculate, (2.8–)3–5(–6) mm;
stamens 20, filaments filiform, (1–)1.5–3 mm, anthers light pink, 0.3–0.5 mm;
carpels 8–20, styles 2.2–3 mm.
9–11 mm diam.;
epicalyx bractlets elliptic to oblong, 1.2–2 mm;
hypanthium shallowly cupulate, 1–2 × 2.5–5(–7) mm;
sepals 2–3.5 mm, bluntly acute;
petals golden yellow, broadly oblanceolate to spatulate or broadly obovate, (2–)2.5–3.5(–4) mm;
stamens 10, filaments 0.6–1.8 mm, anthers yellow, 0.6–0.8 mm;
carpels 10–30, styles 0.9–1.3 mm.
light brown, 1.2–1.3 mm.
greenish tan to light brown, 1.2–1.5 mm.
Ivesia pityocharis
Ivesia pygmaea
Of conservation concern.
Ivesia pityocharis is known only from the Pine Nut Mountains, Douglas County. Plants are somewhat intermediate between those of I. kingii and I. sericoleuca in having relatively shallow hypanthia and loosely sericeous vestiture. Hairs on petioles and stem bases of I. pityocharis are to 4 mm; those of I. kingii are 1 mm and generally appressed-ascending.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Ivesia pygmaea is known only from the southern Sierra Nevada in California, where it overlaps the range of I. lycopodioides var. megalopetala. Stamen number is the only unequivocal way to distinguish between the two, though I. pygmaea is also more generally setose with somewhat shallower hypanthia. It is also more likely to have much-branched caudices and can form mats in rocky sites. Larger plants with relatively open cymes have sometime been segregated as I. chaetophora; this probably represents ecological and phenotypic plasticity.
Early reports of Ivesia pygmaea from Nevada are based on P. A. Rydberg’s (1898) mistaken understanding of the type locality, which is actually in Tulare County, California. A reported occurrence from the northern Sierra Nevada in Nevada (J. T. Kartesz 1987) is presumably based on the same source as the unconfirmed report of I. lycopodioides from the same locality (D. D. Keck 1938).
The correct name for this species if treated as Potentilla is P. nubigena Greene; P. decipiens Greene is a later homonym and illegitimate.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CalFlora
WildflowerSearch
iNaturalist
USDA Plants Database
