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Ivesia longibracteata

Castle Crags ivesia, longbract mousetail

Shockley's ivesia, sky mousetail

Habit Plants green, ± tufted; taproot ± stout, not fleshy. Plants green to grayish green, ± densely matted.
Stems

ascending to erect, 0.3–1.2 dm.

prostrate to ascending, 0.2–1.5 dm.

Basal leaves

weakly planar to loosely ± cylindric, (0.5–)2–4(–6) cm; sheathing base glandular abaxially, otherwise glabrous;

petiole 0.5–2 cm, hairs 0.2–1 mm;

leaflets 5–6 per side, 2–6 mm, ± short-hirsute, glandular-puberulent, lobes 2–7, oblanceolate to spatulate or obovate, apex not setose.

tightly to loosely cylindric, (1–)2–12(–14) cm; sheathing base strigose to hirsute abaxially;

petiole 0.5–4 cm;

lateral leaflets (3–)5–15(–18) per side, separate to overlapping at least distally, ± flabellate, 1–4(–6) mm, incised to base or nearly so into 2–10(–12) oblanceolate to obovate or elliptic lobes, apex sometimes setose, surfaces ± sparsely hirsute, ± glandular;

terminal leaflets indistinct.

Cauline leaves

1–3, not paired.

(0–)1;

blade vestigial or reduced.

Inflorescences

3–14-flowered, 1–2.5 cm diam.;

glomerules 1.

2–20-flowered, ± open, 0.5–4(–6) cm diam.

Pedicels

1.5–6 mm.

3–10(–12) mm.

Flowers

8–10 mm diam.;

epicalyx bractlets linear to narrowly lanceolate or elliptic, 2.5–5 mm, longer than sepals;

hypanthium shallowly cupulate, 0.5–1 × 2–3 mm;

sepals 1.5–2.5 mm, ± acute;

petals pale yellow, linear to narrowly oblanceolate, 1.5–2.5 mm;

stamens 5, filaments 0.7–1.3 mm, anthers yellow, 0.5–0.8 mm;

carpels 6–11, styles 1–1.5 mm.

5–10 mm diam.;

epicalyx bractlets 5, elliptic or narrowly oblong to ovate, 0.7–2(–3) mm;

hypanthium patelliform, 1–2 × 2.5–4.5(–5) mm;

sepals 1.5–3.5(–4) mm, acute to obtuse;

petals ± yellow, oblanceolate to spatulate or narrowly obovate, 1–3 mm;

stamens 5, filaments 0.8–1.8 mm, anthers yellow, oblong, 0.4–0.9 mm;

carpels 2–5(–6), styles 1.8–2.5 mm.

Achenes

cream to light tan, 1.2–1.5 mm.

greenish cream to light brown, 1.5–2.2(–2.5) mm, smooth, prominently carunculate.

Ivesia longibracteata

Ivesia shockleyi

Phenology Flowering summer.
Habitat Dry crevices of granodioritic igneous rock, in mixed oak-conifer woodlands
Elevation 1200–1400 m (3900–4600 ft)
Distribution
from FNA
CA
[BONAP county map]
from FNA
CA; NV; OR; UT
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

Ivesia longibracteata is known only from the Castle Crags area of Shasta County. The epithet alludes to a diagnostic characteristic unique in the genus: the epicalyx bractlets are longer than the sepals. The plants grow on vertical rock faces, a habitat more characteristic of sect. Setosae; however, the stems are ascending to erect and do not form hanging clumps, and the pedicels are not curved in fruit.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Varieties 2 (2 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Lateral leaflets: lobes 2–5(–7); inflorescences 2–10-flowered, 0.5–3 cm diam.; e California, c, se Oregon, c, n Nevada.
var. shockleyi
1. Lateral leaflets: lobes (4–)6–10(–12); inflorescences 5–20-flowered, (1–)3–4(–6) cm diam.; wc Utah.
var. ostleri
Source FNA vol. 9, p. 236. FNA vol. 9, p. 227.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Setosae
Sibling taxa
I. aperta, I. argyrocoma, I. arizonica, I. baileyi, I. callida, I. campestris, I. cryptocaulis, I. gordonii, I. jaegeri, I. kingii, I. lycopodioides, I. muirii, I. multifoliolata, I. paniculata, I. patellifera, I. pickeringii, I. pityocharis, I. pygmaea, I. rhypara, I. sabulosa, I. santolinoides, 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. pygmaea, I. rhypara, I. sabulosa, I. santolinoides, I. saxosa, I. sericoleuca, I. setosa, I. tweedyi, I. unguiculata, I. utahensis, I. webberi
Subordinate taxa
I. shockleyi var. ostleri, I. shockleyi var. shockleyi
Synonyms Potentilla shockleyi
Name authority Ertter: Syst. Bot. 14: 233, fig. 1. (1989) S. Watson: Proc. Amer. Acad. Arts 23: 263. (1888)
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