groundsels

genus Senecio

Member of groundsels and allies (tribe Senecioneae)
sunflower family (family Asteraceae)
dicots (class Magnoliopsida)
flowering plants (subphylum Angiospermae)

Except for old historical records and extremely rare examples that I don't expect to encounter, there are no other wild species of this genus in the bay area.

Inner phyllaries are the length of the involucre. Outer phyllaries are much reduced.

common groundsel
Senecio vulgaris

55–65 disk flowers
no ray flowers
involucre ± widely cylindric or urn-shaped
inner phyllaries generally black-tipped
outer phyllaries ± inconspicuous, black-tipped
common

coastal burnweed
Senecio minimus

3–5 disk flowers
9–20+ ray flowers, stigma only with no ray petal
involucre cylindric
inner phyllaries generally minutely black-tipped
outer phyllaries inconspicuous
leaves entire, margin sharply and evenly fine-dentate
common

cutleaf burnweed
Senecio glomeratus

8–10 disk flowers
25–35 ray flowers, stigma only with no ray petal
involucre cylindric
phyllaries hairy at base
outer phyllaries inconspicuous
leaves pinnately lobed
common

california groundsel
Senecio aphanactis

8–20 disk flowers
± 5 ray flowers, 0.5–1+ mm
involucre narrowly urn-shaped
inner phyllaries green-tipped [I think Jepson means brown-tipped]
outer phyllaries inconspicuous
herbage glabrous or sparsely hairy
leaves 1-pinnately lobed or dentate
rare

heath groundsel
Senecio sylvaticus

40–50 disk flowers
1–8 ray flowers, 0–2+ mm
involucre cylindric
herbage densely curly-hairy
inner phyllaries often black-tipped
outer phyllaries inconspicuous
leaves 1–2 pinnately lobed or divided
uncommon

rayless ragwort
Senecio aronicoides

40–75 disk flowers
0–2 ray flowers, 4–7 mm
involucre bell-shaped
inner phyllaries green- or black-tipped
outer phyllaries 0–few, inconspicuous to > ½ inner
common

douglas’ threadleaf ragwort
Senecio flaccidus var. douglasii

unknown number of disk flowers
8, 13, or 21 ray flowers, 10–15 mm
involucre bell-shaped
inner phyllaries occasionally black tipped
outer phyllaries ± prominent, often some > ½ inner
shrub or subshrub with shrub-like branching
leaves narrowly linear to thread-like
uncommon

red-purple ragwort
Senecio elegans

100+ disk flowers
13–21 ray flowers, 10–15 mm, deep red-purple or pink-purple

(all others are yellow)

involucre bell-shaped
inner phyllaries black-tipped
outer phyllaries conspicuous, many, graduated, ≤ ± ½ inner, black-tipped
herb
leaves obovate, abruptly narrowed or tapered to petiole, 1–2-pinnately lobed, ultimate margin crenate to dentate
uncommon

Toxicity of dusty miller, rosary beads, rosary pearls, string of beads, string of pearls (Senecio spp.):
4 – Ingestion of these plants, especially in large amounts, is expected to cause serious effects to the heart, liver, kidneys or brain. If ingested in any amount, call the poison center immediately.

4 observed taxons / 4 unobserved taxons / 1 key

Chris’s observations: 10 (5 are research grade)

Locations:

Jacks Peak CP: 2
Alum Rock Park, San Jose
Ansel Adams Wilderness
Coyote Valley OSP
El Corte de Madera OSP
Lexington Reservoir CP
Russian Ridge OSP
San Bruno Mountain State & County Park
Windy Hill OSP

Months:

Feb.: 1
Mar.: 1
Apr.: 1
May: 1
Jun.: 0
Jul.: 0
Aug.: 3
Sep.: 1
Oct.: 2

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Taxon info: iNaturalist – Calflora – Jepson eFlora – FNA

Bay Area species: iNaturalist – Calflora