Ivesia pygmaea

A. Gray

Proc. Amer. Acad. Arts 6: 531. 1865.

Common names: Dwarf ivesia
Endemic
Synonyms: Ivesia chaetophora (Rydberg) Rydberg I. gordonii var. pygmaea (A. Gray) S. Watson Potentilla gordonii var. chaetophora (Rydberg) Jepson P. nubigena Greene
Treatment appears in FNA Volume 9. Treatment on page 231. Mentioned on page 228, 230, 236.

Plants green, tufted to ± tightly matted; taproot stout, not fleshy. Stems decumbent to erect, 0.3–1 (–1.5) dm. Basal leaves 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 (1–) 5–10-flowered, 0.8–3 cm diam.; glomerules usually 1. Pedicels 1.5–8 (–10) mm. Flowers 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 greenish tan to light-brown, 1.2–1.5 mm.


Phenology: Flowering summer.
Habitat: Dry rocky slopes, sometimes in horizontal rock crevices, in high-elevation sagebrush communities, subalpine to alpine conifer woodlands, alpine tundra
Elevation: 2700–4000 m

Discussion

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.

Selected References

None.

Lower Taxa

None.

"dm" is not declared as a valid unit of measurement for this property.

... more about "Ivesia pygmaea"
not carunculate +
greenish tan +  and light-brown +
1.2mm +  and 1.5mm +
longer than wide +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
Barbara Ertter +  and James L. Reveal +
A. Gray +
compound +  and simple +
opposite +  and alternate +
8 cm80 mm <br />0.08 m <br /> (12 cm120 mm <br />0.12 m <br />) +
1 cm10 mm <br />0.01 m <br /> (8 cm80 mm <br />0.08 m <br />) +
20 cm200 mm <br />0.2 m <br /> (25 cm250 mm <br />0.25 m <br />) +
narrowly oblong +  and filiform planar +
reduced +
0.5 cm5 mm <br />0.005 m <br /> (20 cm200 mm <br />0.2 m <br />) +
reduced +
elongate +
free +  and distinct +
branched +  and simple +
Dwarf ivesia +
not +  and aggregated +
2700–4000 m +
elliptic +  and oblong +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
0.9 cm9 mm <br />0.009 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
unisexual +  and bisexual +
not +  and aggregated +
deciduous +
obliquely ovoid +  and reniform +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
loose +  and capitate +
Dry rocky slopes, sometimes in horizontal rock crevices, in high-elevation sagebrush communities, subalpine to alpine conifer woodlands, alpine tundra +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
(1-)5-10-flowered +
0.8 cm8 mm <br />0.008 m <br /> (3 cm30 mm <br />0.03 m <br />) +
crassinucellate +
opposite +  and alternate +
winter-marcescent +
deciduous +  and persistent +
0.4 cm4 mm <br />0.004 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
, +  and distinct +
not +  and distinguishable +
short-villous +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
oblanceolate +  and narrowly oblong or oval +
verticillate +
toothed +, unlobed +  and lobed +
inferior +  and superior +
clustered +, biseriate +  and superposed +
0.8 cm8 mm <br />0.008 m <br /> (1 cm10 mm <br />0.01 m <br />) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
0 (?) +  and 4 (?) +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
free +  and distinct +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (4 cm40 mm <br />0.04 m <br />) +
Flowering summer. +
adnate +, free +, connate +  and distinct +
Proc. Amer. Acad. Arts +
not arillate +
persistent +
free +  and distinct +
erect +  and spreading +
0.2 cm2 mm <br />0.002 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
free +  and distinct +
branched +  and simple +
reddish +, grayish +  and green +
decumbent +  and erect +
2 +  and 20 +
palmate +  and pinnate +
deciduous +
distinct +
subterminal +
filiform +
rough-thickened +
0.09 cm0.9 mm <br />9.0e-4 m <br /> (0.13 cm1.3 mm <br />0.0013 m <br />) +
Ivesia chaetophora +, I. gordonii var. pygmaea +, Potentilla gordonii var. chaetophora +  and P. nubigena +
not fleshy +
Ivesia pygmaea +
Ivesia sect. Ivesia +
species +
inconspicuous +
stipelike +, elongate +, less flat +  and conic or turbinate +
enlarged +
tufted +  and rosetted +
plant +  and matted +
glabrate +  and sparsely densely glandular-puberulent +