FNA: Ivesia santolinoides vs. Ivesia pygmaea

	Ivesia santolinoides	Ivesia pygmaea
	mouse tail ivesia, Sierra mousetail, silver mousetail, stellariopsis	dwarf ivesia, dwarf mousetail
Habit	Plants ± grayish to silvery.	Plants green, tufted to ± tightly matted; taproot stout, not fleshy.
Stems	ascending to erect, (1–)1.5–4 dm.	decumbent to erect, 0.3–1(–1.5) dm.
Basal leaves	mousetail-like (individual leaflets scarcely distinguishable), 3–10 cm; sheathing base densely strigose abaxially; petiole 0.5–1.5 cm; leaflets 60–80 per side, 0.6–1.5 mm, lobes (0–)3–5, obovate to oval, densely villous.	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.
Cauline leaves		(0–)1, not paired.
Inflorescences	(10–)30–200-flowered, 3–8(–30) cm diam.	(1–)5–10-flowered, 0.8–3 cm diam.; glomerules usually 1.
Pedicels	5–30 mm.	1.5–8(–10) mm.
Flowers	5–8 mm diam.; epicalyx bractlets oblong to broadly ovate or orbiculate, 0.2–0.5 mm; hypanthium 0.5–1.5 × 2–3 mm; sepals 1–2 mm, apex obtuse to acute; petals white, broadly obovate to orbiculate, 2–2.5 mm; stamens 15, filaments 1.2–1.8 mm, anthers purple, broadly obcordate to pouch-shaped, 0.3–0.4 mm; carpels 1, styles 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.
Achenes	mottled grayish brown, 1.7–2 mm.	greenish tan to light brown, 1.2–1.5 mm.
2n	= 28.

	Ivesia santolinoides	Ivesia pygmaea
Phenology	Flowering summer.	Flowering summer.
Habitat	Dry sandy granitic soil, decomposed granite accumulations, ledges and outcrops, in montane and subalpine conifer woodlands	Dry rocky slopes, sometimes in horizontal rock crevices, in high-elevation sagebrush communities, subalpine to alpine conifer woodlands, alpine tundra
Elevation	1500–3600 m (4900–11800 ft)	2700–4000 m (8900–13100 ft)
Distribution	CA [WildflowerSearch map] [BONAP county map]	CA [WildflowerSearch map] [BONAP county map]
Discussion	Ivesia santolinoides is found on loose granitic substrates in the Sierra Nevada, Transverse Ranges, and San Jacinto Mountains from El Dorado to Riverside counties. The species is easily recognized by its silvery mousetail-like leaves and erect, diffuse inflorescences with small, plumlike flowers. (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.)
Source	FNA vol. 9, p. 246.	FNA vol. 9, p. 231.
Parent taxa	Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Stellariopsis	Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia
Sibling taxa	I. aperta, I. argyrocoma, I. arizonica, I. baileyi, I. callida, I. campestris, I. cryptocaulis, I. gordonii, I. jaegeri, I. kingii, I. longibracteata, I. lycopodioides, I. muirii, I. multifoliolata, I. paniculata, I. patellifera, I. pickeringii, I. pityocharis, I. pygmaea, I. rhypara, I. sabulosa, I. saxosa, I. sericoleuca, I. setosa, I. shockleyi, I. tweedyi, I. unguiculata, I. utahensis, I. webberi	I. aperta, I. argyrocoma, I. arizonica, I. baileyi, I. callida, I. campestris, I. cryptocaulis, I. gordonii, I. jaegeri, I. kingii, I. longibracteata, I. lycopodioides, I. muirii, I. multifoliolata, I. paniculata, I. patellifera, I. pickeringii, I. pityocharis, I. rhypara, I. sabulosa, I. santolinoides, I. saxosa, I. sericoleuca, I. setosa, I. shockleyi, I. tweedyi, I. unguiculata, I. utahensis, I. webberi
Synonyms	Potentilla santolinoides, Stellariopsis santolinoides	I. chaetophora, I. gordonii var. pygmaea, Potentilla gordonii var. chaetophora, P. nubigena
Name authority	A. Gray: Proc. Amer. Acad. Arts 6: 531. (1865)	A. Gray: Proc. Amer. Acad. Arts 6: 531. (1865)
Web links	Local floras: CA Local Web sites: CalFlora, CalPhotos WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: CA Local Web sites: CalFlora, CalPhotos WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Ivesia pygmaea

mouse tail ivesia, Sierra mousetail, silver mousetail, stellariopsis

dwarf ivesia, dwarf mousetail

Habit

Plants ± grayish to silvery.

Plants green, tufted to ± tightly matted; taproot stout, not fleshy.

Stems

ascending to erect, (1–)1.5–4 dm.

decumbent to erect, 0.3–1(–1.5) dm.

Basal leaves

mousetail-like (individual leaflets scarcely distinguishable), 3–10 cm; sheathing base densely strigose abaxially;

petiole 0.5–1.5 cm;

leaflets 60–80 per side, 0.6–1.5 mm, lobes (0–)3–5, obovate to oval, densely villous.

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.

Cauline leaves

(0–)1, not paired.

Inflorescences

(10–)30–200-flowered, 3–8(–30) cm diam.

(1–)5–10-flowered, 0.8–3 cm diam.;

glomerules usually 1.

Pedicels

5–30 mm.

1.5–8(–10) mm.

Flowers

5–8 mm diam.;

epicalyx bractlets oblong to broadly ovate or orbiculate, 0.2–0.5 mm;

hypanthium 0.5–1.5 × 2–3 mm;

sepals 1–2 mm, apex obtuse to acute;

petals white, broadly obovate to orbiculate, 2–2.5 mm;

stamens 15, filaments 1.2–1.8 mm, anthers purple, broadly obcordate to pouch-shaped, 0.3–0.4 mm;

carpels 1, styles 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.

Achenes

mottled grayish brown, 1.7–2 mm.

greenish tan to light brown, 1.2–1.5 mm.

= 28.

Ivesia pygmaea

Phenology

Flowering summer.

Habitat

Dry sandy granitic soil, decomposed granite accumulations, ledges and outcrops, in montane and subalpine conifer woodlands

Dry rocky slopes, sometimes in horizontal rock crevices, in high-elevation sagebrush communities, subalpine to alpine conifer woodlands, alpine tundra

Elevation

1500–3600 m (4900–11800 ft)

2700–4000 m (8900–13100 ft)

Distribution

[WildflowerSearch map]

[BONAP county map]

[WildflowerSearch map]

[BONAP county map]

Discussion

Ivesia santolinoides is found on loose granitic substrates in the Sierra Nevada, Transverse Ranges, and San Jacinto Mountains from El Dorado to Riverside counties. The species is easily recognized by its silvery mousetail-like leaves and erect, diffuse inflorescences with small, plumlike flowers.

(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.)

Source

FNA vol. 9, p. 246.

FNA vol. 9, p. 231.

Parent taxa

Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Stellariopsis

Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia

Sibling taxa

I. aperta, I. argyrocoma, I. arizonica, I. baileyi, I. callida, I. campestris, I. cryptocaulis, I. gordonii, I. jaegeri, I. kingii, I. longibracteata, I. lycopodioides, I. muirii, I. multifoliolata, I. paniculata, I. patellifera, I. pickeringii, I. pityocharis, I. pygmaea, I. rhypara, I. sabulosa, I. saxosa, I. sericoleuca, I. setosa, I. shockleyi, I. tweedyi, I. unguiculata, I. utahensis, I. webberi

I. aperta, I. argyrocoma, I. arizonica, I. baileyi, I. callida, I. campestris, I. cryptocaulis, I. gordonii, I. jaegeri, I. kingii, I. longibracteata, I. lycopodioides, I. muirii, I. multifoliolata, I. paniculata, I. patellifera, I. pickeringii, I. pityocharis, I. rhypara, I. sabulosa, I. santolinoides, I. saxosa, I. sericoleuca, I. setosa, I. shockleyi, I. tweedyi, I. unguiculata, I. utahensis, I. webberi

Synonyms

Potentilla santolinoides, Stellariopsis santolinoides

I. chaetophora, I. gordonii var. pygmaea, Potentilla gordonii var. chaetophora, P. nubigena

Name authority

A. Gray: Proc. Amer. Acad. Arts 6: 531. (1865)

Web links

Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).

Choose a data source: Flora of North America

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Ivesia santolinoides

Ivesia pygmaea

Ivesia santolinoides

Ivesia pygmaea