Ivesia sericoleuca

(Rydberg) Rydberg in N. L. Britton et al.
in N. L. Britton et al., N. Amer. Fl. 22: 284. 1908.
Common names: Plumas ivesia
Conservation concernEndemic
Basionym: Horkelia sericoleuca Rydberg Monogr. N. Amer. Potentilleae, 144, plate 85. 1898
Synonyms: Potentilla sericoleuca (Rydberg) J. T. Howell
Treatment appears in FNA Volume 9. Treatment on page 240. Mentioned on page 238, 239, 241, 242.

Plants silvery to grayish green; glands usually sparse, sometimes abundant. Stems decumbent to ascending, 1.5–4.5 dm. Basal leaves 10–20(–30) cm; sheathing base densely strigose abaxially; stipules absent; petiole 2–6(–10) cm, hairs abundant, usually spreading, 1–4 mm; leaflets 20–35 per side, loosely overlapping, 3–15 mm, lobes 0–4, oblanceolate to elliptic, hairs abundant, spreading to ascending, (0.5–)1–3(–4) mm. Cauline leaves 3–8(–10). Inflorescences 20–120-flowered, (2–)4–14 cm diam., flowers mostly arranged in several to many tight glomerules of 5–10 flowers. Pedicels 1–3(–12) mm. Flowers 10–15 mm diam.; epicalyx bractlets narrowly lanceolate to narrowly elliptic, (1.5–)2–2.5(–3) mm; hypanthium campanulate to shallowly turbinate, 1.5–3 × 2.5–4.5(–5) mm, often nearly as deep as wide; sepals sometimes purple-suffused, 3–5.5 mm, acute to acuminate; petals white, broadly spatulate to broadly obovate or obcordate, 4–7 mm; stamens 20, filaments filiform, 1.5–3 mm, anthers white to cream, 0.5–0.7 mm; carpels 2–7, styles 2.5–4 mm. Achenes brown, 2–3 mm. 2n = 28.


Phenology: Flowering summer.
Habitat: Dry gravelly meadows, margins of seeps, usually on vernally saturated volcanic soil, in sagebrush and grass communities, conifer woodlands
Elevation: 1300–2300 m

Discussion

Of conservation concern.

Ivesia sericoleuca is known from valleys and flats in the northern Sierra Nevada. Many historic collections were identified and distributed as I. unguiculata, and circumscriptions prior to 1962 include I. aperta (hence reports from Nevada).

Hairs are usually dense in plants of Ivesia sericoleuca, such that the leaves, and occasionally the stems and branches, are silvery gray, especially in Sierra Valley and the Feather River drainage. Plants in the Truckee River drainage tend to be less hairy with redder stems, less glomerate inflorescences, shallower hypanthia, and more conspicuous glandularity.

As mentioned by J. T. Howell (1962), the chromosome count given for Ivesia sericoleuca by P. A. Munz (1959) most likely was based on a collection of I. aperta var. aperta. The chromosome count given here is instead based on Kruckeberg 3665, originally distributed as I. pickeringii.

Selected References

None.

Lower Taxa

None.

... more about "Ivesia sericoleuca"
Barbara Ertter +  and James L. Reveal +
(Rydberg) Rydberg in N. L. Britton et al. +
Horkelia sericoleuca +
Plumas ivesia +
1300–2300 m +
Dry gravelly meadows, margins of seeps, usually on vernally saturated volcanic soil, in sagebrush and grass communities, conifer woodlands +
Flowering summer. +
in N. L. Britton et al., N. Amer. Fl. +
Conservation concern +  and Endemic +
Potentilla sericoleuca +
Ivesia sericoleuca +
Ivesia sect. Unguiculatae +
species +