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FNA | Family List | FNA Vol. 20 | Asteraceae | Isocoma

3. Isocoma menziesii (Hooker & Arnott) G. L. Nesom, Phytologia. 70: 93. 1991.

Pacific jimmyweed , Menzies’ goldenbush

Pyrrocoma menziesii Hooker & Arnott, Bot. Beechey Voy., 351. 1838

Herbage glabrous or villlous, sometimes stipitate-glandular, not resinous. Leaf blades obovate to spatulate or oblanceolate to nearly linear, 5–40 mm, margins entire or toothed to lobed. Involucres (6–)7–9 × 6–8 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). Florets (15–)18–25(–28); corollas 5–7 mm. Cypsela ribs not forming apical horns.

Varieties 5 (5 in the flora): California, nw Mexico.

1 Leaf blades mostly obovate, thick-fleshy, margins coarsely serrate; stems decumbent, prostrate, or pendent; herbage glabrous   3d Isocoma menziesii var. sedoides
+ 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 (1) Herbage essentially glabrous, stipitate-glandular   (3)
+ Herbage glabrous, villous, or tomentose, not prominently glandular or glands beneath other vestiture   (4)
3 (2) 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   3a Isocoma menziesii var. decumbens (in part)
+ 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   3b Isocoma menziesii var. diabolica
4 (2) Plants densely tomentose or villous   (5)
+ Plants glabrous or glabrate   (6)
5 (4) 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   3a Isocoma menziesii var. decumbens (in part)
+ 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   3e Isocoma menziesii var. vernonioides (in part)
6 (4) Leaf margins entire or with 1–2 pairs of teeth or shallow lobes distally   3c Isocoma menziesii var. menziesii
+ At least proximal leaves toothed along most margins   3e Isocoma menziesii var. vernonioides (in part)


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