Ivesia callida
Ivesia pygmaea
Tahquitz ivesia, Tahquitz mousetail
dwarf ivesia, dwarf mousetail
usually pendent or prostrate to ascending, sometimes nearly erect, 0.2–1.5 dm.
decumbent to erect, 0.3–1(–1.5) dm.
± loosely cylindric to weakly planar, 1–7 cm; sheathing base sparsely strigose abaxially;
petiole 0.3–3 cm;
lateral leaflets (1–)5–8 per side, slightly overlapping, elliptic to flabellate, 2–6(–7) mm, incised nearly to base into (0–)2–4 oblanceolate to elliptic lobes, apex sometimes ± setose, surfaces loosely long-strigose, sparsely glandular;
terminal leaflets indistinct.
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.
(1–)2;
blade reduced.
(0–)1, not paired.
1–10(–15)-flowered, open, (0.5–)2–5 cm diam.
(1–)5–10-flowered, 0.8–3 cm diam.;
glomerules usually 1.
5–15 mm.
1.5–8(–10) mm.
7–10 mm diam.;
epicalyx bractlets 5, narrowly lanceolate, 1.5–3 mm;
hypanthium patelliform, 0.5–1 × 2–3 mm;
sepals 2–3.5 mm, acute;
petals white, obovate, 2–3.5 mm;
stamens 20, filaments 1.5–3 mm, anthers maroon, subrotund, 0.2–0.3 mm;
carpels 4–8, styles 1.5–1.8 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.
greenish white to light tan, 1.5 mm, smooth to lightly rugose, ± carunculate.
greenish tan to light brown, 1.2–1.5 mm.
Ivesia callida
Ivesia pygmaea
Of conservation concern.
Ivesia callida occurs in the Tahquitz Peak area of the San Jacinto Wilderness Area, San Jacinto Mountains, Riverside County, where two populations are known (K. Berg 1983). Plants form tight mats in horizontal crevices and loose pendent clumps on vertical rock faces.
(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.)
CA
WildflowerSearch
iNaturalist
USDA Plants Database
