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coastal goldenbush, Menzies' goldenbush, Pacific jimmyweed, white flower goldenbush

common goldenbush, common jimmyweed

Herbage

glabrous or villlous, sometimes stipitate-glandular, not resinous.

usually glabrous, leaves never stipitate-glandular, almost always resinous.

Leaf

blades obovate to spatulate or oblanceolate to nearly linear, 5–40 mm, margins entire or toothed to lobed.

blades oblanceolate, 15–30(–50) mm, margins usually pinnatifid (lobes in 1–3 pairs, spreading, linear, apically spinescent), sometimes entire or only proximal leaves pinnatifid.

Involucres

(6–)7–9 × 6–8 mm.

5–6(–7) × 2.5–4 mm.

Florets

(15–)18–25(–28);

corollas 5–7 mm.

12–15;

corollas 4.5–6 mm.

Phyllary

apices green to yellowish, not aristate, sometimes with weakly developed, non- or weakly spinulose projection, gland-dotted, without resin pockets or pockets small, weakly developed (var. decumbens and var. menziesii).

apices green to greenish yellow or yellowish (markedly thickened), not aristate, slightly or not gland-dotted, without resin pockets.

Cypsela

ribs not forming apical horns.

ribs not forming hornlike extensions.

2n

= 12.

Isocoma menziesii

Isocoma coronopifolia

Phenology Flowering (May–)Jun–Oct.
Habitat Alkaline sandy flats, matorral, shrublands
Elevation 200–500 m [700–1600 ft]
Distribution
from FNA
CA; nw Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
TX; Mexico (Coahuila, Nuevo León, Tamaulipas)
[BONAP county map]
Discussion

Varieties 5 (5 in the flora).

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

Populations with at least the distal leaves entire have been called Isocoma pedicellata, and these apparently segregate geographically, at least to some extent (G. L. Nesom 1991c). Some plants have both entire and pinnatifid leaves; the distinction does not appear to warrant formal recognition.

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

Key
1. Leaf blades mostly obovate, thick-fleshy, margins coarsely serrate; stems decumbent, prostrate, or pendent; herbage glabrous
var. sedoides
1. Leaf blades obovate to oblanceolate, usually not thick-fleshy, margins entire or toothed (if so then at least stems densely villous); stems erect to ascending or decumbent; herbage glabrous, villous, tomentose, or stipitate-glandular
→ 2
2. Herbage essentially glabrous, stipitate-glandular
→ 3
2. Herbage glabrous, villous, or tomentose, not prominently glandular or glands beneath other vestiture
→ 4
3. Stems prostrate to decumbent or ± erect; leaves 5–22 × 2–4 mm; heads in corymbiform to loose, paniculiform arrays; cypselae 2.3–3.6 mm; San Diego County southward
var. decumbens
3. Stems strictly erect; leaves 20–40 × 4–10 mm; heads in corymbiform arrays; cypselae (3.8–)4.5–5 mm; San Benito and Santa Clara counties
var. diabolica
4. Plants densely tomentose or villous
→ 5
4. Plants glabrous or glabrate
→ 6
5. Herbage finely and closely grayish-arachnoid-tomentose; leaf blades narrowly oblanceolate, 5–22 × 2–4 mm, margins entire or with 1–2 pairs of teeth distally
var. decumbens
5. Herbage hirtellous, villoso-pilose, or densely gray-tomentose (hairs flattened, vitreous, long); leaf blades linear to oblanceolate or spatulate-oblong, 10–40 × 2–6(–9) mm, at least proximal leaves with toothed margins
var. vernonioides
6. Leaf margins entire or with 1–2 pairs of teeth or shallow lobes distally
var. menziesii
6. At least proximal leaves toothed along most margins
var. vernonioides
Source FNA vol. 20, p. 442. FNA vol. 20, p. 444.
Parent taxa Asteraceae > tribe Astereae > Isocoma Asteraceae > tribe Astereae > Isocoma
Sibling taxa
I. acradenia, I. arguta, I. azteca, I. coronopifolia, I. drummondii, I. humilis, I. pluriflora, I. rusbyi, I. tenuisecta
I. acradenia, I. arguta, I. azteca, I. drummondii, I. humilis, I. menziesii, I. pluriflora, I. rusbyi, I. tenuisecta
Subordinate taxa
I. menziesii var. decumbens, I. menziesii var. diabolica, I. menziesii var. menziesii, I. menziesii var. sedoides, I. menziesii var. vernonioides
Synonyms Pyrrocoma menziesii Linosyris coronopifolia, I. coronopifolia var. pedicellata, I. pedicellata
Name authority (Hooker & Arnott) G. L. Nesom: Phytologia 70: 93. (1991) (A. Gray) Greene: Erythea 2: 111. (1894)
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